Meat replacement product, method for manufacturing same and twin screw extruder

Abstract

In order to improve the mouth feel of meat replacement production, meat replacement products and improvements of high moisture protein texturized extrusion are invented. The inventors have found that appropriate selection of extrusion parameters and starting materials comprising mechanically processed starch-containing grains such that the formation of an emulsion between the starch and a protein melt forming the protein matrix can be prevented or reduced to such an extent that substantial amounts of unbound starch are present in the protein matrix. The presence of unbound starch in the protein matrix has been observed to improve the mouth feel and maintain an acceptable mouth feel for extended periods of time. The present application encompasses independent claims for large quantities of meat replacement products and methods.

Description

This application is a divisional application of patent application 2019801002306 titled "Meat alternative products, methods for manufacturing them, and twin-screw extruders" filed by the applicant on July 13, 2019. Technical Field

[0001] The present invention relates to meat alternative products and methods for their manufacture. In addition, the present invention relates to the use of starch in food products. Background Art

[0002] In recent years, many people have switched to vegetarian or vegan diets, or at least increased the share of vegetables and vegetable products in their diets. While ecological concerns are a reason for some, it seems obvious that vegetables and products made from vegetables should be a central part of a healthy diet. Many consumers find it difficult to ensure their daily protein intake using vegetables or products made from vegetables, and some find it time-consuming to prepare protein-containing ingredients for steaming or baking.

[0003] Therefore, there is a market for producing vegetarian or vegan foods on an industrial basis by extrusion cooking. Extrusion cooking is a continuous process that enables the production of texturized proteins, which are unique products made by extrusion. Extrusion enables the control of functional properties such as density, rate and time of rehydration, shape, product appearance, and texture.

[0004] For the extrusion of meat alternative products (also known as meat analogues) or texturized vegetable products, twin-screw extruders are commonly used. There are mainly two categories of extrusion cooking methods for preparing meat alternative products.

[0005] One type of meat alternative product is produced by low-moisture protein texturization extrusion. Such products have a moisture content between 10% and 40% (the moisture content during extrusion is between 15% and 40%). They typically have a spongy texture and need to be rehydrated before consumption. These products are commonly used as chopped meat substitutes or extenders in meat products, but they can hardly mimic fibrous whole-muscle meats.

[0006] Another type of meat alternative product is manufactured by high-moisture protein texturization extrusion. Such products have a moisture content between 40% and 80%. They generally resemble muscle foods more than meat alternative products manufactured by low-moisture texturization extrusion.

[0007] Meat alternative products are typically manufactured by mixing at least one protein matrix-forming component such as protein isolate or protein concentrate (which is generally referred to as the protein component), possible starch-containing microparticles, possible oil, and extruding the components mixed into a slurry in an extruder configured to perform protein texturization extrusion.

[0008] In tests conducted by the inventors using high-moisture protein texturizing extrusion, it was found that the texture of freshly extruded meat alternative products is generally very appealing. However, after a relatively short period of time (usually in the range of a few minutes, typically 5 - 10 minutes), when the meat alternative products cool, the texture becomes unacceptable.

[0009] Currently, meat alternative products manufactured by high-moisture protein texturizing extrusion are typically sold deep-frozen. Alternatively, the meat alternative products are sold shredded or sliced, making this unacceptable texture less noticeable. SUMMARY OF THE INVENTION

[0010] A first object of the present invention is to improve the texture of meat alternative products manufactured by high-moisture protein texturizing extrusion such that the improved texture is comparable to that of steamed chicken drumsticks and the improved texture is maintained for a further extended period of time, such as overnight, or 24 hours, without the need to freeze the meat alternative products.

[0011] When the linear compressibility of a sample is relatively high while the cylindrical compressibility is relatively low, it can be assumed that the texture is comparable to that of steamed chicken drumsticks. When measured using a texture analyzer model TA.XTPlus (Stable Micro Systems, Inc., Surrey, UK) equipped with a 294.2 N (30 kg) load cell (detector sensor) and a sharp blade, the linear compressibility is preferably between 300 g and 1500 g. When measured using a texture analyzer TA.XTPlus (Stable Micro Systems, Inc.) equipped with a 294.2 N (30 kg) load cell (detector sensor) with a cylindrical probe (model "P / 36R", 36 mm radius edge cylindrical probe - aluminum - AACC standard probe for bread firmness), the cylindrical compressibility is preferably between 7000 g and 17500 g. For the measurement, samples with a height between 7.0 and 12.0 mm should be used. The width and length of the samples are preferably selected to be 40 mm. Figure 11 Illustrates the preferred analytical methods for cutting force and compressive force that should be used.

[0012] Alternatively, when the compressibility and chewing characteristics experienced are confirmed by a group of testers to be similar to those of steamed chicken drumsticks, it can be said that the texture of the meat alternative product is comparable to that of steamed chicken drumsticks.

[0013] The object can be achieved by a meat substitute product according to any one of independent items 1, 3, 9, 10, 11, or 60, or any combination of two, three, four, or all of these independent items, and by a method for manufacturing a meat substitute product according to any one of independent items 16, 19, 20, 21, 22, 24, or 53, or any combination of two, three, four, five, or all of these independent items.

[0014] The second object of the present invention is to increase the starch solubility in a meat substitute product manufactured by high moisture protein texturizing extrusion. This object can be achieved by a meat substitute product according to any one of independent items 9 and 11 and by a method according to any one of independent items 21 and 22.

[0015] The third object of the present invention is to control the starch solubility in a meat substitute product manufactured by high moisture protein texturizing extrusion. This object can be achieved by a meat substitute according to independent item 10 and by a method according to independent item 20.

[0016] The fourth object relates to the use of a novel starch composition in a food product.

[0017] The fifth object relates to the improvement of a twin-screw extruder. This object can be achieved by a twin-screw extruder according to item 41.

[0018] The sixth object relates to improving the texture of a meat substitute product manufactured by high moisture protein texturizing extrusion. This object can be achieved by a method according to parallel independent item 42 and by product item 52.

[0019] The dependent items describe advantageous aspects of the meat substitute product and the method for manufacturing the meat substitute product. The above items are shown below. Item 1. A meat substitute product, comprising: An extrudate manufactured by high moisture protein texturizing extrusion, i.e., such that the moisture content during extrusion is between 40% - 80%, and the extrudate has a substantially linearly oriented continuous protein fiber matrix structure, the matrix containing disruptions in the matrix structure. Some of the disruptions in the matrix structure are in the form of cavities having walls at least partially coated with gelatinized starch clusters formed from starch such that when measured on the extrudate, at least 5.1%, preferably at least 5.2% of the starch is soluble starch located at the disruptions in the matrix structure and not emulsified by the matrix structure. Item 2. The meat substitute product according to item 1, wherein: the soluble starch is in the form of clusters and phase-separated from the protein phase and not emulsified by the protein. Item 3. A meat alternative product, wherein: the meat alternative product comprises an extrudate, the extrudate is produced by high moisture protein texturization extrusion and has a substantially linearly oriented continuous protein fiber matrix structure, the extrudate comprises gelatinized starch clusters located at the breakage of the matrix structure and not emulsified by the matrix structure, such that when the extrudate is measured, i) when the protein content of the extrudate is greater than 55% by weight but less than 70% by weight, at least 10.5% of the starch in the extrudate is washable starch, ii) when the protein content of the extrudate is at least 70% by weight but less than 90% by weight, at least 15% of the starch in the extrudate is washable starch, iii) when the protein content of the extrudate is at least 90% by weight but equal to or less than 99% by weight, at least 16% of the starch in the extrudate is washable starch, wherein the indicated % by weight is based on a dry basis. Item 4. The meat alternative product according to item 3, wherein: the washable starch is washable in water at a temperature of 50°C. Item 5. The meat alternative product according to item 3 or 4, wherein: the washable starch is located at the breakage of the matrix structure and not emulsified by the matrix structure. Item 6. The meat alternative product according to item 5, wherein: some of the breakages in the matrix structure are in the form of cavities, the cavities having walls at least partially coated with gelatinized starch clusters formed from washable starch. Item 7. The meat alternative product according to any one of the preceding items 1 and / or 6, wherein: the starch clusters comprise washable starch that is washable in water at a temperature of 50°C. Item 8. The meat alternative product according to any one of the preceding items, comprising: starch clusters having a size (e.g., length) greater than about 100 μm. Item 9. A meat alternative product, wherein: the meat alternative product comprises an extrudate having a substantially linearly oriented continuous protein fiber matrix structure, the extrudate comprises starch, and wherein: the extrudate is produced by high moisture protein texturization extrusion, in which the starch-containing grains are gelatinized and the protein forming the protein matrix is melted, such that the starch-containing grains are gelatinized before they are substantially pulverized by the extruder screw. Item 10. A meat alternative product, wherein: the meat alternative product comprises an extrudate having a substantially linearly oriented continuous protein fiber matrix structure, the extrudate comprises starch, and wherein: the extrudate is produced by high moisture protein texturization extrusion, in which the starch-containing grains are gelatinized and the protein forming the protein matrix is melted, such that: (a) before the protein in the gelatinized starch-containing grains and the protein matrix forms an emulsion, and (b) before the gelatinized starch forms a complete barrier that prevents the formation of a continuous crosslinked matrix of protein fibers, the protein melts. Item 11. A meat substitute product, comprising: An extrudate having a substantially linearly oriented continuous protein fiber matrix structure, the extrudate being manufactured by high moisture protein texturizing extrusion and comprising starch located at the breaks in the matrix structure and not emulsified by the matrix structure, wherein: Some of the breaks in the matrix structure are in the form of cavities having walls at least partially coated with clusters of gelatinized starch formed from starch. Item 12. The meat substitute product according to item 11, wherein: the clusters of gelatinized starch formed from starch are formed from soluble starch or washable starch. Item 13. The meat substitute product according to any one of the preceding items, wherein: the extrudate is an extrudate manufactured using a high moisture protein texturizing extrusion method with a twin screw extruder having a long cooling die. Item 14. The meat substitute product according to item 13, wherein: the length of the long cooling die is at least 300 mm, preferably at least 1000 mm, and most preferably between 1000 mm and 5000 mm. Item 15. The meat substitute product according to any one of items 1-14, wherein: the meat substitute product is in the form of a thick block, rib, small piece, meat slice, steak or shish kebab-like slice, or in the form of a shish kebab-like stratified layer in yogurt or vegan yogurt and spices. Item 16. A method for manufacturing a meat substitute product, characterized in that: a meat substitute product is produced using an extruder configured to perform high moisture protein texturizing extrusion, in which starch-containing grains are gelatinized and the protein forming the protein matrix melts, the meat substitute product being an extrudate having a substantially linearly oriented continuous protein fiber matrix structure, the extrudate comprising clusters of gelatinized starch located at the breaks in the matrix structure and not emulsified by the matrix structure, The extrudate contains starch, and when measured on the extrudate, at least 5.1%, preferably at least 5.2% of the starch is soluble starch. Item 17. The method according to item 16, wherein: the soluble starch is located at the breaks in the matrix structure and is not emulsified by the matrix structure. Item 18. The method according to item 16 or 17, wherein: some of the disruptions in the matrix structure are in the form of cavities having walls at least partially coated with gelatinized starch clusters formed from starch, preferably soluble starch. Item 19. A method for manufacturing a meat alternative product, characterized in that: a meat alternative product is produced using an extruder configured to perform high-moisture protein texturization extrusion, in which starch grains are gelatinized and the protein forming the protein matrix is melted, and the meat alternative product is an extrudate having a continuous protein fiber matrix structure, the extrudate containing gelatinized starch clusters formed from starch, located at disruptions in the matrix structure and not emulsified by the matrix structure, such that when the extrudate is measured, i) when the protein content of the extrudate is greater than 55% by weight but less than 70% by weight, at least 10.5% of the starch is washable starch, ii) when the protein content of the extrudate is at least 70% by weight but less than 90% by weight, at least 15% of the starch is washable starch, iii) when the protein content of the extrudate is at least 90% by weight but equal to or less than 99% by weight, at least 16% of the starch is washable starch, wherein the indicated % by weight is based on a dry basis. Item 20. A method for manufacturing a meat alternative product, characterized in that: a meat alternative product is produced using an extruder configured to perform high-moisture protein texturization extrusion, in which starch grains are gelatinized and the protein forming the protein matrix is melted, and the meat alternative product is an extrudate having a continuous protein fiber matrix structure, the extrudate containing starch such that: (a) before the gelatinized starch grains form an emulsion with the protein of the protein matrix, and (b) before the gelatinized starch forms a complete barrier preventing the formation of a cross-linked matrix of continuous protein fibers, the protein forming the protein matrix is melted. Item 21. A method for manufacturing a meat alternative product, characterized in that: a meat alternative product is produced using an extruder configured to perform high-moisture protein texturization extrusion such that the moisture content during extrusion is between 40% and 80%, wherein in the extrusion, starch grains are gelatinized and the protein forming the protein matrix is melted, and the resulting meat alternative product is an extrudate having a continuous protein fiber matrix structure, the extrudate containing starch, wherein: the step of heating the slurry in the extruder is carried out such that: the starch grains are gelatinized before they are substantially pulverized by the extruder screw. Item 22. A method for manufacturing a meat alternative product, characterized in that: a meat alternative product is produced using an extruder configured to perform high-moisture protein texturization extrusion, in which starch grains are gelatinized and the protein forming the protein matrix is melted, the meat alternative product is an extrudate having a continuous protein fiber matrix structure, and the extrudate contains gelatinized starch clusters formed from starch, located at the sites of matrix structure disruption and not emulsified by the matrix structure. Item 23. The method according to Item 22, wherein: some of the sites of matrix structure disruption are in the form of cavities having walls at least partially coated with gelatinized starch clusters formed from starch, preferably formed from soluble starch or washable starch. Item 24. A method for manufacturing a meat alternative product, the method comprising the steps of: a) feeding a mixture into an extruder configured to perform high-moisture protein texturization extrusion, the mixture comprising: a1) at least one protein matrix-forming component, such as a protein isolate or a protein concentrate, and a2) mechanically processed starch-containing grains having a particulate volume of at least 0.125 mm 3 , preferably at least 1 mm 3 , most preferably at least 6 mm 3 ; b) feeding water into the extruder; c) heating the mixture in the extruder to gelatinize the starch-containing grains; d) after achieving the starch gelatinization, further heating the mixture in the extruder to melt at least one protein matrix-forming component; and e) extruding the mixture through an extrusion die at a temperature between 70 °C and 100 °C wherein: i) heating step c) is carried out by impact heating such that the starch-containing grains are gelatinized before they are substantially pulverized by the extruder screw; and ii) heating step d) is carried out by impact heating such that: (a) before the gelatinized starch forms an emulsion with the protein matrix-forming component, and (b) before the gelatinized starch forms a complete barrier preventing the formation of a continuous protein fiber crosslinked matrix, the protein melting temperature of the protein matrix-forming component is reached. Item 25. The method according to Item 24, wherein: the starch-containing grains are soaked before being fed into the extruder. Item 26. The method according to item 24 or 25, wherein: the starchy grain is treated before being fed into the extruder such that the starch is gelatinized before being fed into the extruder. Item 27. The method according to any one of items 24 - 25, wherein: water is fed to the starchy grain at an elevated temperature. Item 28. The method according to item 27, wherein: the water temperature is higher than 60 °C, preferably higher than 65 °C. Item 29. The method according to item 27, wherein: the water temperature is higher than 75 °C. Item 30. The method according to any one of the preceding items 24 - 29, wherein: the heating step d) is carried out at a temperature between 140 °C and 200 °C. Item 31. The method according to any one of the preceding items 24 - 30, wherein: the heating step d) is carried out such that protein melting occurs between 1 s and 40 s after step b), preferably between 10 s and 30 s. Item 32. The method according to any one of the preceding items 24 - 31, wherein: the heating step c) is carried out such that starch gelatinization occurs between 0 s and 18 s after step b), preferably between 1 s and 15 s. Item 33. The method according to any one of the preceding items 24 - 32, wherein: before the starchy grain is ground by the extruder screw into a volume per particle less than 5000 μm 3 and preferably before the starchy grain is ground by the extruder screw into a volume per particle less than 0.001 mm 3 before, the heating step c) is carried out. Item 34. The method according to any one of the preceding items 24 - 33, wherein: after the heating step d), at a temperature not higher than the temperature in the heating step d), preferably between 90 °C and the temperature in the heating step d), the mixture is continuously extruded for more than 5 s, preferably more than 10 s. Item 35. The method according to any one of the preceding items 16 - 34, wherein: the mechanically processed starchy grain comprises one or more of the following or consists of one or more of the following: cereal flakes (such as compressed, rolled or flaked), steel cut grains, hulled pearled grains, crushed grains, hulled but unpearled grains, provided that: hulled but unpearled oat grains, hulled but unpearled rye grains, hulled but unpearled barley grains, hulled but unpearled corn grains are excluded. Item 36. The method according to any one of the preceding items 16 - 35, wherein: the mechanically processed starch-containing grains comprise one or more of the following or consist of one or more of the following: oats, barley, rye, wheat, rice, corn, lentils, chickpeas, mung beans, fava beans, peas, quinoa, pigeon peas, sorghum, buckwheat, however excluding: dehulled but unpearled oat grains, dehulled but unpearled rye grains, dehulled but unpearled barley grains, dehulled but unpearled corn grains. Item 37. The method according to any one of the preceding items 16 - 36, wherein: the extrusion step is carried out using an extrusion die having a length greater than 300 mm, preferably greater than 1000 mm, and most preferably between 1000 mm and 5000 mm. Use of insoluble washable starch in the form of clusters in a meat alternative food product produced by high moisture protein texturizing extrusion. Item 39. The use of the insoluble washable starch according to item 38, wherein: the meat alternative food product is manufactured using the method according to any one of the preceding items 16 - 37. Item 40. The use of the insoluble washable starch according to item 38 or 39, wherein: the insoluble washable starch is contained in the form of clusters having a size greater than about 100 μm. Item 41. A twin-screw extruder for high moisture protein texturizing extrusion, comprising: a screw barrel (138) for accommodating an extruder screw (126), the extruder screw (126) defining the direction of movement of the material in the extruder (13) relative to the barrel (138), the barrel (138) further comprising a first inlet hole (139) for receiving solid components into the extruder (13) and a second inlet hole (140) for receiving liquid into the extruder (13), the second inlet hole (140) being located downstream of the first inlet hole (139) in the flow direction, the extruder (13) i) is connected to a warm water supply having a temperature of at least 50 °C, or ii) comprises a heating element (14) configured to heat water from a water supply to a temperature of at least 50 °C before passing the water from the water supply into the second inlet hole (140); The extruder further comprises a long cooling die (125) having a length greater than 300 mm, preferably having a length between 300 mm and 5000 mm, and most preferably between 1000 mm and 3000 mm. Item 42. A method for manufacturing a meat substitute product by high-moisture protein texturizing extrusion, wherein the improvement comprises: selecting extrusion parameters and starting materials, the starting materials comprising at least: i) a protein component, preferably a protein isolate or a protein concentrate or a mixture thereof; ii) mechanically processed starch-containing grains; and iii) cereal flours, such that the formation of an emulsion between the starch and the protein melt forming the protein matrix is substantially prevented or reduced to such an extent that a substantial amount of the starch in the extrudate will be in the form of gelatinized starch clusters and not bound by the protein matrix. Item 43. The method according to item 42, wherein: the clusters have a size greater than about 100 μm. Item 44. The method according to item 42 or 43, wherein: the controlled extrusion parameters include, or are: the water feed temperature and / or the heating profile, such as along the extrusion screw and in the cooling die, such that the starting materials are shock-heated in the extruder. Item 45. The method according to any one of items 42-44, wherein: the hardness or compressibility of the meat substitute product is controlled by controlling the ratio of the amount of soluble starch to the total amount of starch and / or the weight % of soluble starch in the meat substitute product. Item 46. The method according to item 45, wherein: the ratio of the amount of soluble starch to the total amount of starch and / or the weight % of soluble starch is controlled such that the linear compressibility is between 300 g and 1500 g, and the cylindrical compressibility is between 7000 g and 17500 g. Item 47. The method according to item 46, wherein: the linear and cylindrical compressibilities are measured at least 24 hours after extrusion. Item 48. The method according to any one of items 42-47, wherein: the amount of starch not bound by the protein matrix is determined as soluble starch. Item 49. The method according to item 48, wherein: the compressibility is controlled by changing the extrusion parameters such that, in the meat substitute product after extrusion, the ratio of the amount of soluble starch to the total amount of starch is between 3 wt% and 10 wt%, and / or the soluble starch content is between 0.03 wt% and 1.1 wt%. Item 50. The method according to any one of the preceding items 42-49, wherein: the mechanically processed starch-containing grains comprise one or more of the following or consist of one or more of the following: cereal flakes (such as compressed, rolled or flaked), steel-cut grains, dehulled pearled grains, crushed grains, dehulled but unpearled grains, excluding: dehulled but unpearled oat grains, dehulled but unpearled rye grains, dehulled but unpearled barley grains, dehulled but unpearled corn grains. Item 51. The method according to any one of the preceding items 42 - 50, wherein: the mechanically processed starch-containing grains comprise one or more of or consist of one or more of the following: oats, barley, rye, wheat, rice, corn, lentils, chickpeas, mung beans, broad beans, peas, quinoa, pigeon peas, sorghum, buckwheat, excluding: dehulled but unpearled oat grains, dehulled but unpearled rye grains, dehulled but unpearled barley grains, dehulled but unpearled corn grains. Item 52. A meat substitute product, the meat substitute product being manufactured by the method according to any one of method items 42 - 51. Item 53. A method for manufacturing a meat substitute product, the method comprising the following steps: a) Feeding a mixture into an extruder configured to perform high moisture protein texturization extrusion, the mixture comprising: a1) At least one protein matrix forming component, such as a protein isolate or a protein concentrate, and a2) Mechanically processed starch-containing grains, which are steel cut grains and have a particulate volume of at least 0.125 mm 3 , preferably at least 1 mm 3 , most preferably at least 6 mm 3 ; b) Feeding water into the extruder so that the moisture content during extrusion is between 40% - 80%; c) Heating the mixture in the extruder to gelatinize the starch-containing grains; d) After achieving the starch gelatinization, further heating the mixture in the extruder to melt at least one protein matrix forming component; and e) Extruding the mixture through an extrusion die at a temperature between 70 °C and 100 °C, wherein: i) Heating step c) is performed by impact heating such that the starch-containing grains gelatinize before they are substantially pulverized by the extruder screw; and ii) Heating step d) is performed by impact heating such that: (a) Before the gelatinized starch forms an emulsion with the protein matrix forming component, and (b) Before the gelatinized starch forms a complete barrier that prevents the formation of a continuous protein fiber crosslinked matrix, the protein melting temperature of the protein matrix forming component is reached. Item 54. The method according to item 53, wherein: the steel cut grains are soaked in water before being fed into the extruder. Item 55. The method according to item 53, wherein: the steel cut grains are not soaked when being fed into the extruder. Item 56. The method according to any one of Items 53 - 55, wherein: the steel - cut grains comprise steel - cut oats. Item 57. The method according to any one of Items 53 - 56, wherein: the steel - cut oats are replaced by any one of the following: steel - cut barley, rice grains, broken rice, pearled barley, pearled rye, pearled wheat, pearled oats, pea - crushed seeds (e.g., with a particle size of 2 mm), broad - bean - crushed seeds, chickpea - crushed seeds, lentil seeds, or a mixture thereof. Item 58. The method according to any one of Items 53 - 57, wherein: in the method, (a) an extrusion - shock heating temperature setting is used in combination (a) and (b) hot water is used as the liquid feed to increase starch solubility. Item 59. The method according to any one of Items 53 - 58, wherein: in the method, (a) the grains and water are mixed, and (b) the grains combined with water are heated early enough before the starch in the grains is emulsified by the protein matrix. Item 60. A meat - alternative product manufactured by the method according to any one of Items 54 - 59.

[0020] Advantages of the Invention According to a first aspect, a meat - alternative product shows an improved taste that is maintained for a long time. The meat - alternative product is manufactured by high - moisture protein texturizing extrusion and comprises an extrudate having a continuous protein fiber matrix structure with a substantially linear orientation, and the extrudate contains starch, wherein at least 5.1%, preferably at least 5.2%, of the starch is soluble starch.

[0021] Accordingly, a meat - alternative product showing an improved taste that is maintained for a long time can be manufactured by a manufacturing method that uses an extruder configured to perform high - moisture protein texturizing extrusion. In the extruder, starch - containing grains are gelatinized and the protein that forms the protein matrix melts, such that the meat - alternative product is an extrudate having a continuous protein fiber matrix structure and the extrudate contains starch, wherein at least 5.1%, preferably at least 5.2%, of the starch is soluble starch.

[0022] The soluble starch is preferably located at the breakage of the matrix structure and is not emulsified by the matrix structure. Most preferably, some of the breakages in the matrix structure are in the form of cavities, and the walls of the cavities are at least partially coated with gelatinized starch clusters formed from starch, preferably formed from soluble starch.

[0023] According to a second aspect, which replaces or supplements the first aspect, a meat alternative product exhibits an improved texture maintained over a long period of time. The meat alternative product is manufactured by high moisture protein texturizing extrusion and comprises an extrudate having a continuous protein fiber matrix structure with a substantially linear orientation. The extrudate comprises starch such that: i) when the protein content of the extrudate is greater than 55 wt% but less than 70 wt%, at least 10.5% of the starch is washable starch, ii) when the protein content of the extrudate is at least 70 wt% but less than 90 wt%, at least 15% of the starch is washable starch, iii) when the protein content of the extrudate is at least 90 wt% but equal to or less than 99 wt%, at least 16% of the starch is washable starch, wherein the indicated wt% is based on a dry basis.

[0024] Accordingly, a meat alternative product exhibiting an improved texture maintained over a long period of time can be manufactured by a manufacturing method using an extruder configured to perform high moisture protein texturizing extrusion. In the extruder, starch-containing grains are gelatinized and proteins for forming a protein matrix are melted. The meat alternative product is an extrudate having a continuous protein fiber matrix structure. The extrudate comprises starch such that: i) when the protein content of the extrudate is greater than 55 wt% but less than 70 wt%, at least 10.5% of the starch is washable starch, ii) when the protein content of the extrudate is at least 70 wt% but less than 90 wt%, at least 15% of the starch is washable starch, iii) when the protein content of the extrudate is at least 90 wt% but equal to or less than 99 wt%, at least 16% of the starch is washable starch, wherein the indicated wt% is based on a dry basis.

[0025] Preferably, the washable starch is located at the disrupted sites of the matrix structure and is not emulsified by the matrix structure. Most preferably, some of the disrupted sites in the matrix structure are in the form of cavities having walls at least partially coated with gelatinized starch clusters formed from the washable starch. The washable starch is washable in water at a temperature of 50 °C, which is below the gelatinization temperature of the starch.

[0026] According to a third aspect, which replaces the first and second aspects or supplements one or both of them, a meat alternative product exhibits an improved texture that is maintained over a long period of time. The meat alternative product is manufactured by high-moisture protein texturizing extrusion and comprises an extrudate having a continuous protein fiber matrix structure with a substantially linear orientation. The extrudate comprises starch, and wherein the extrudate is manufactured using a high-moisture protein texturizing extrusion method in which starch-containing grains are gelatinized and the protein forming the protein matrix is melted such that: The starch-containing grains are gelatinized before they are substantially pulverized by an extruder screw.

[0027] Accordingly, a meat alternative product that exhibits an improved texture maintained over a long period of time can be manufactured by a manufacturing method for producing a meat alternative product that uses an extruder configured to perform high-moisture protein texturizing extrusion in which starch-containing grains are gelatinized and the protein forming the protein matrix is melted. The meat alternative product is an extrudate having a continuous protein fiber matrix structure that comprises starch, wherein: the step of heating the slurry in the extruder is carried out such that the starch-containing grains are gelatinized before they are substantially pulverized by the extruder screw.

[0028] The manufacturing method of the meat alternative product increases starch solubility, and accordingly, the meat alternative product has increased starch solubility.

[0029] According to a fourth aspect, which replaces the first, second, and third aspects or supplements one, two, or all of them, a meat alternative product exhibits an improved texture that is maintained over a long period of time. The meat alternative product is manufactured by high-moisture protein texturizing extrusion and comprises an extrudate having a continuous protein fiber matrix structure with a substantially linear orientation. The extrudate comprises starch, and wherein: the extrudate is manufactured using a high-moisture protein texturizing extrusion method in which starch-containing grains are gelatinized and the protein forming the protein matrix is melted such that: (a) before the gelatinized starch-containing grains form an emulsion with the protein of the protein matrix, and (b) before the gelatinized starch forms a complete barrier that prevents the formation of a crosslinked matrix of continuous protein fibers, the protein is melted.

[0030] Accordingly, a meat alternative product showing an improved taste maintained over a long time can be manufactured by a manufacturing method for producing a meat alternative product, which uses an extruder configured to perform high-moisture protein texturizing extrusion, in which starch-containing grains are gelatinized and the protein forming the protein matrix is melted, the meat alternative product being an extrudate having a continuous protein fiber matrix structure, the extrudate containing starch, such that: (a) before the gelatinized starch-containing grains and the protein of the protein matrix form an emulsion, and (b) before the gelatinized starch forms a complete barrier preventing the formation of a continuous protein fiber crosslinked matrix, the protein forming the protein matrix is melted.

[0031] The manufacturing method of the meat alternative product enables the control of starch solubility, and accordingly, the meat alternative product can have a controlled starch solubility.

[0032] According to a fifth aspect, which replaces the first, second, third, and fourth aspects, or supplements one, two, three, or all of them, a meat alternative product shows an improved taste maintained over a long time, the meat alternative product being manufactured by high-moisture protein texturizing extrusion and comprising: an extrudate having a continuous protein fiber matrix structure with a substantially linear orientation, the extrudate containing starch located at the breakage of the matrix structure and not emulsified by the matrix structure.

[0033] Accordingly, a meat alternative product showing an improved taste maintained over a long time can be manufactured by a manufacturing method which uses an extruder configured to perform high-moisture protein texturizing extrusion, in which starch-containing grains are gelatinized and the protein forming the protein matrix is melted, the meat alternative product being an extrudate having a continuous protein fiber matrix structure, the extrudate containing starch located at the breakage of the matrix structure and not emulsified by the matrix structure.

[0034] The manufacturing method of the meat alternative product increases starch solubility, and accordingly, the meat alternative product has an increased starch solubility.

[0035] Particularly advantageously, some of the breakages in the matrix structure can be in the form of cavities having walls at least partially coated with clusters of gelatinized starch formed from starch, preferably from soluble starch or washable starch.

[0036] The advantages specifically arising from the fifth aspect are that the breaks and in particular the cavities at least partially (preferably completely) coated with starch clusters (and phase-separated starch clusters) prevent the hardening of the extrudate (resulting from the strengthening of gel hardness). The breaks and at least partially coated cavities formed by the starch clusters (and phase-separated starch clusters) act as a new type of disruptive complex that prevents the further formation of protein-protein interactions between protein fibers after extrusion. They are different from and superior to other disruptive particles known to the inventors, such as starch, flour, insoluble salts, dietary fiber, pregelatinized starch, gases, which either (a) disappear after extrusion (e.g., gases), or (b) will be emulsified by the protein matrix during extrusion (e.g., insoluble salts, dietary fiber, flour, starch), or (c) become factors that accelerate or worsen the deterioration (hardening) of the extrudate (such as the retrogradation effect of starch, starch gel aging refers to the rearrangement of amylose and amylopectin molecules in starch and the resulting recrystallization, which usually leads to a leathery texture and hard texture of starch-containing foods such as bread. These phenomena occur most rapidly at temperatures slightly above freezing point).

[0037] According to a sixth aspect, which instead of the first, second, third, fourth, and fifth aspects, or is supplemented to one, two, three, four, or all of them, a meat alternative product showing an improved taste maintained for a long time can be manufactured by a manufacturing method as follows: a) Feeding a mixture into an extruder configured to perform high-moisture protein texturizing extrusion, the mixture comprising: a1) At least one protein matrix-forming component, such as protein isolate or protein concentrate, and a2) Mechanically processed starch-containing grains having a particle volume of at least 0.125 mm 3 、preferably at least 1 mm 3 、most preferably at least 6 mm 3 ; b) Feeding water into the extruder; c) Heating the mixture in the extruder to gelatinize the starch-containing grains; d) After achieving starch gelatinization, further heating the mixture in the extruder to melt at least one protein matrix-forming component; and e) Extruding the mixture through an extrusion die at a temperature between 70 °C and 100 °C wherein: i) Heating step c) is carried out by impact heating such that the starch-containing grains are gelatinized before they are substantially pulverized by the extruder screw; and ii) Heating step d) is carried out by impact heating such that: a) before forming an emulsion from the gelatinized starch and the protein matrix-forming components, and b) reaching the protein melting temperature of the protein matrix-forming components before the gelatinized starch forms a complete barrier that prevents the formation of a continuous cross-linked matrix of protein fibers.

[0038] "Particle volume" and "volume per particle" are terms that describe the particle size. They can be calculated based on the dimensions of the particles, for example: - When the particles are mostly close to a cubic shape, their particle volume can be calculated as length times width times thickness; - When the particles are close to a spherical shape, the particle volume can be calculated using the value of the diameter of the particles. For example, the average particle size (diameter) can be calculated using the Dv0.5 value in conventional particle size distribution analysis methods.

[0039] The particle volume is at least 0.125 mm 3 indicating that the average volume of the particles is 0.125 mm 3 . By sieving measurement, the particle size diameter of typical commercial oat flour is less than 0.300 mm, from which the average particle volume can be calculated not to exceed 0.014 mm 3 .

[0040] Traditionally, in high-moisture protein texturizing extrusion, a heating temperature profile with a gradually increasing temperature from the material feed side to the other end of the screw chamber in the extruder is used because it is expected that protein melting occurs at this end of the extruder and the components gradually absorb heat and increase their temperature. Under the concept of impact heating of the present invention, the materials to be heated to the target temperature in the extruder are heated significantly faster, preferably within a few seconds after feeding them into the extruder, which is before they are conveyed to the last part of the extruder screw chamber.

[0041] Preferably, water is fed into the starch-containing grains at an elevated temperature. The specific heat capacity of water is about 220% higher than the specific heat capacity of protein powder and flour. Therefore, feeding water at an elevated temperature can heat the materials in the extruder to reach the target temperature in a significantly shorter time.

[0042] Preferably, the starch-containing grains are treated before being fed into the extruder so that the starch is gelatinized before being fed into the extruder in such a way that the size (particle volume) of the grains remains at least the same or even increases.

[0043] The inventors have observed a stable consistency in the first five aspects in the studied samples with improved taste. In addition, the object of the present invention can be solved by the method according to the sixth aspect.

[0044] According to any aspect, the meat alternative products and methods have in common that the extrudate is an extrudate made by a high moisture texturizing extrusion method, preferably using a twin screw extruder with a long cooling die (the cooling die preferably has a length greater than 300 mm, most preferably greater than 1000 mm). In the extrusion, the mechanically processed starch-containing grains are processed with at least one protein isolate / concentrate / combination of the former, oil, and spices to make a slurry that will then be extruded.

[0045] The term "mechanically processed" refers to cereal grains - such as compressed, rolled, or flaked - steel cut grains, hulled and pearled grains, crushed grains, or hulled but unpearled grains, excluding: hulled but unpearled oat grains, hulled but unpearled rye grains, hulled but unpearled barley grains, hulled but unpearled corn grains.

[0046] The mechanically processed starch-containing grains preferably comprise one or more of the following or consist of one or more of the following: oats, barley, rye, wheat, rice, corn, lentils, chickpeas, mung beans, broad beans, peas, quinoa, pigeon peas, sorghum, buckwheat, excluding: hulled but unpearled oat grains, hulled but unpearled rye grains, hulled but unpearled barley grains, hulled but unpearled corn grains.

[0047] Preferably, the meat alternative product is further processed so that it can be sold in the form of thick blocks, chops, small pieces, slices, steaks, or slices in the form of doner meat, or in the form of a layered laminate in the form of a doner kebab in yogurt or vegan yogurt and spices.

[0048] The use of insoluble washable starch in the form of clusters in food products may bring interesting possibilities to the food industry.

[0049] The inventors have observed with a microscope equipped with polarized light that the starch in the extruded product does not have the "Maltese cross" feature that it had before extrusion or before being immersed in hot water. This indicates that the starch in the extruded product is gelatinized.

[0050] After being tested by starch washability, the protein fiber matrix structure of the chopped extruded product remains insoluble and undamaged. After being steamed in water in a pressure cooker at 110 °C for 10 minutes, the protein fiber matrix structure of the meat alternative product also remains insoluble and undamaged. The cutting force of the meat alternative product steamed in the pressure cooker remains between 40% and 50% of the cutting force before being steamed in the pressure cooker. These are important differences from the properties of products produced by other extrusion methods that are not high moisture texturizing extrusion. Products produced by other extrusion methods basically dissolve, soften, or collapse after being steamed in water or soaked in warm water overnight.

[0051] According to another aspect, a method for manufacturing a meat substitute product by high-moisture protein texturizing extrusion can be improved by selecting extrusion parameters and starting materials, the starting materials comprising at least: i) a protein component, preferably a protein isolate or a protein concentrate or a mixture thereof, ii) mechanically processed starch-containing grains, and iii) cereal flour, such that the formation of an emulsion between the starch and the protein melt forming the protein matrix is substantially prevented or reduced to such an extent that a large amount of starch not bound to the protein matrix is present in the extruded meat substitute product.

[0052] The controlled extrusion parameters preferably include the water feed temperature and / or the heating profile (such as along the extrusion screw and in the cooling die), such that the starting materials are subjected to impact heating in the extruder.

[0053] Advantageously, the hardness or compressibility of the meat substitute product is controlled by controlling the starch solubility in the meat substitute product. Most advantageously, the starch solubility is controlled such that the linear compressibility is between 300 g and 1500 g, and the cylindrical compressibility is between 7000 g and 17500 g. Preferably, the linear and cylindrical compressibilities are measured at least 24 hours after extrusion.

[0054] Advantageously, the amount of starch not bound to the protein matrix is determined as soluble starch. Preferably, the compressibility is controlled by changing the extrusion parameters such that the proportion of the amount of soluble starch in the extruded meat substitute product relative to the total amount of starch (starch solubility) is between 3 wt% and 10 wt%. In this case, the soluble starch content in the extruded meat substitute product is between 0.03 wt% and 1.10 wt%. Description of the Drawings

[0055] The meat substitute product and the method for manufacturing the meat substitute product will be described in more detail below with reference to the drawings, wherein: Figure 1 are photographs of Samples 5, 7, and 8; Figure 2A is an X-ray microtomography (Micro-CT) scan image of Sample 5 taken after soaking in water at 60 °C for 24 hours and air drying; Figure 2B is an X-ray microtomography (Micro-CT) scan image of Sample 8 taken after soaking in water at 60 °C for 24 hours and air drying. This sample is cut in the same manner as Figure 2A above.

[0056] Figure 3Schematically shows the relationship between the observed starch solubility and the compressive force required for the compressed meat substitute product (exponential curve fitting of the measured points); Figure 4 Shows the particle weight distribution of the extruded material affected by the composition and the extrusion heating temperature profile for Experiments 1 - 6; Figure 5 Shows the results of the compression tests on dry (unsoaked) steel - cut oats versus soaked steel - cut oats (soaked in hot water); Figure 6A and 6B Are microscopic images (10x magnification) of samples taken from Sample No. 2; Figure 6C and 6D Are microscopic images (10x magnification) of samples taken from Sample No. 2; Figure 6E and 6F Are microscopic images (10x magnification) of samples taken from Sample No. 6; Figure 6G and 6H Are microscopic images (20x magnification) of samples taken from Sample No. 6; Figure 7A Is a microscopic image of a sample of the washable starch washed out from Sample No. 2 with water at 50°C; Figure 7B Is a microscopic image of a sample of the washable starch washed out from Sample No. 2 with water at 50°C; Figure 8 Is an example of a food made from a meat substitute product (Sample No. 2) after being torn into pieces; Figure 9 Is an example of a food made from a meat substitute product (Sample No. 2) where the extruded product is torn into pieces, pickled slices (left), the extruded product is battered, the extruded product is breaded and deep - fried in oil (right); Figure 10 Shows the pea protein gelation affected by the heating temperature; Figure 11 Schematically shows the cutting force and compression force analysis method; Figure 12A and B schematically show the schematic arrangement of the extrusion process; Figure 13 Schematically shows the quantitative analysis method for soluble starch and washable starch; Figure 14A Shows the starch coated on the inner surface of the cavity of the extruded product; Figure 14B Shows the inner surface of the cavity of the extruded product observed by iodine staining; Figure 14CShows the inner surface of the cavity of the extruded product observed by iodine staining; Figure 14D and Figure 14E Shows the inner surface of the cavity of the extruded product observed by iodine staining; and Figure 15 Shows photographs of Sample No. 2 before (top photo) and after (bottom two photos) expansion.

[0057] In all the figures, the same reference numerals refer to the same components. Detailed Description

[0058] I: Current Situation and Objectives The texture of cooked chicken drumstick meat is different from that of chicken breast fillets. The difference in texture is particularly related to tenderness. Cooked chicken breast fillets generally require a relatively high compression force at a 40% compression rate, indicating that cooked chicken breast fillets generally have relatively low compressibility.

[0059] As described in the introduction section, the inventors have been working on meat alternative products manufactured by high-moisture protein texturization extrusion. Figure 12A Schematically shows an extruder 12 configured to implement a conventional high-moisture protein texturization extrusion process. In the extruder 12, components in powder form are mixed in a mixer 121, and the mixer 121 is connected to a supply line 122 that leads to an inlet hopper 123. The extruder 12 has a liquid feed line 124 connected (preferably via a valve 130 and a collection tank 131 to achieve a constant water volume flow rate) to a conventional tap water supply (tap water usually has a temperature not higher than room temperature or, for example, 30 °C). The extruder 12 has a long cooling die 125. Extrusion is carried out using two extruder screws, and thus it is called a "twin-screw extruder".

[0060] The research focus is on improving the texture and finding ways to produce meat alternative products manufactured by high-moisture protein texturization extrusion such that the meat alternative products have suitable high compressibility and chewiness so that their texture is as close as possible to that of cooked chicken drumstick meat. In addition, in order to optimize the texture, the meat alternative products should have a long continuous fiber protein matrix structure.

[0061] On the market, there are meat alternative products manufactured by high-moisture protein texturization extrusion, which are sold chopped or shredded, and when the meat alternative products are cooled after extrusion, they have a texture somewhat comparable to that of cooked chicken breast fillets to a certain extent. Table I shows some data of selected existing meat alternative products compared with tofu, chicken breast, and chicken drumstick.

[0062] Table I: Physical Properties of Selected Meat Alternative Products on the Market ​ It is a trademark registered by Food for Progress Scandinavia Ab of Sweden in at least the European Union, the United States, New Zealand, Switzerland, Australia, the Islands and Norway. The product "Thick Block" has ingredients of water, soy protein (23%) and salt. Among these products that the inventors were able to test, there is no similar steamed chicken drumstick meat. Steamed chicken drumstick meat is more tender, more compressible and has a more flexible structure than steamed chicken breast slices.

[0063] Due to the long continuous fiber protein matrix structure of steamed chicken drumstick meat, steamed chicken drumstick meat has a chewiness comparable to that of chicken breast slices.

[0064] In the tests conducted by the inventors using high moisture protein texturizing extrusion, we found that the taste of freshly extruded meat alternative products manufactured using high moisture protein texturizing extrusion is generally very appealing.

[0065] However, after a relatively short period of time (usually within a few minutes, typically 5 to 10 minutes), when the meat alternative product cools, the taste becomes unacceptable. This unacceptable taste stems from the meat alternative product losing its tenderness, becoming less compressible, and the structure of the meat alternative product becoming less flexible.

[0066] Currently, most meat alternative products manufactured using high moisture protein texturizing extrusion are sold frozen deeply. After thawing, these products will have a taste comparable to that of steamed chicken breast slices, which is far from similar to that of steamed chicken drumstick meat.

[0067] In order to improve the taste of meat alternative products manufactured using low moisture extrusion protein texturizing, it is known to add microparticles to the extrudate, such as already including starch; cereal flour; soluble and insoluble polymer fibers such as pea fiber, cellulose, agar-agar, xanthan gum (such as in U.S. Patent Application Publication 2016 / 0205985A1); insoluble salts such as gypsum (such as in U.S. Patent 5,922,392); and fats that disrupt protein fibers to tenderize the extruded product to produce meat alternative products (such as in U.S. Patent Application Publication 2016 / 0205985A1).

[0068] However, most of these compounds are very small in size before extrusion (less than 100 μm in each dimension), or will be split into small parts during extrusion (less than 100 μm in each dimension). In practice, they will all be homogenized by the extruder screw and emulsified by the protein material covering them.

[0069] Tolstoguzov [Reference 1] has studied and described in detail different types of emulsions in protein extrusion, including emulsions of polysaccharides in proteins. Tolstoguzov found that the emulsion systems extruded under protein texturizing extrusion conditions are different from the typical water-in-water or oil-in-water emulsions existing at temperatures below 140 °C. Protein-coated polysaccharide emulsions can be considered as emulsions of polysaccharide melts in protein melts. During the method for manufacturing meat alternative products, i.e., in the high-moisture protein texturizing extrusion process, the protein is the main component. Based on a dry basis, the protein usually accounts for between 50% and 100% of the weight of the extruded raw material. Generally, in an extruder, vegetable proteins suitable for such extrusion processes can be melted at heating temperatures between 140 °C and 200 °C. Thus, the protein can form a continuous phase.

[0070] Therefore, the microparticles disclosed in US2016 / 0205985 A1 and 5,922,392 will be dispersed in the protein and form a dispersed phase. The dispersed microparticles are stably trapped or embedded within the continuous phase, evenly distributed throughout the continuous phase, and have a small particle size.

[0071] The spinneretless spinning effect in extrusion results in the formation of an anisotropic (fibrous or lamellar) structure of the heterogeneous liquid system in the flow.

[0072] In the final stage of the extrusion process, the shapes of the emulsion, liquid filaments, and anisotropic structure are fixed by the rapid gelation of the protein phase with a gelation time shorter than the lifetime of the liquid filaments. After this, if the protein matrix structure or the protein layer covering the dispersed microparticles does not split apart, the dispersed microparticles remain uniformly dispersed, firmly embedded, and can hardly be separated from the protein matrix by mechanical forces (such as centrifugation, gravity) or by extraction (such as washing with water, water extraction).

[0073] When producing meat alternative products by protein texturizing extrusion, it is known that the known methods of including microparticles in extrusion will tenderize the extruded product to a certain extent, especially when the extruded product is freshly produced and before cooling and storing overnight. The microparticles can disrupt the protein fibers by being in the middle of the protein fibers or between adjacent protein fibers.

[0074] The addition of such particulates can also dilute the concentration (proportion) of protein in the composition to be extruded, where the protein forms a protein fiber matrix and contributes to the strength of the extruded product. As such, the addition of particulates can soften the extruded product, especially when the product is fresh and warm prior to being stored overnight at a chilled temperature (e.g., between 0 °C and 6 °C). In low moisture protein texturizing extrusion for the production of meat alternative products (e.g., the moisture content of the material during extrusion is between 15% and 40%), the extruded product mostly has a large amount of expansion and contains a large number of air bubbles between the protein fibers. The expansion and the air bubbles are attributed to a large amount of water evaporation occurring when the extruded material just exits the extrusion die at a high temperature (e.g., above 100 °C). In such a case, the disrupted protein fibers are further separated by the air bubbles and are fixed in positions separated (far from) each other. Thus, in low moisture protein texturizing extrusion for the production of meat alternative products, the disruptive effect from these particulates can be somewhat attractive.

[0075] However, in high moisture protein texturizing extrusion for the production of meat alternative products (e.g., the moisture content of the material during extrusion is between 40% and 80%), the expansion of the extruded material is much less, and there are much fewer air bubbles evenly distributed between the protein fibers to disrupt their crosslinking between adjacent fibers.

[0076] Akdogan [Reference 2] found that the reduced expansion level in high moisture protein texturizing extrusion is caused by an increased concentration of water during extrusion. More specifically, extrusions with higher moisture contents have different distributions of shear (usually less shear force exists in high moisture protein texturizing extrusion), mixing, mechanical heat (usually less mechanical heat dissipation exists in high moisture protein texturizing extrusion), and convective heat. Due to a much lower melt viscosity and a much lower pressure buildup in the extrusion barrel, the viscous dissipation of energy in the extrusion barrel for high moisture content extrusions is much less. The pressure along the die is much lower, and this is thus part of the reason for the extremely low to non-existent expansion at the die. The extruded material is cooled with a long cooling die during high moisture protein texturizing extrusion, and thus water evaporation is greatly reduced. It is also known from the background art that when the starch content of the extruded material is low and when the starch gelatinization level is low, the expansion level of the extruded material leaving the extrusion die will be low. The low viscosity of the extruded material associated with high moisture content also causes it to be somewhat unable to maintain the expansion stably and prevent it from collapsing into a dense sheet.

[0077] Differences in moisture content during extrusion can also lead to changes in the protein-protein forces that are the major contributors to the stable protein matrix. Lin et al. [Reference 3] found that under high-moisture extrusion (e.g., when the moisture content during extrusion is between 40% and 80%), a large portion of the proteins are linked and stabilized by hydrogen bonds, and disulfide bonds and hydrophobic interactions are not the major forces stabilizing the proteins. In contrast, under low-moisture extrusion (e.g., when the moisture content during extrusion is between 30% and 40%), the major important protein matrix stabilizing forces are disulfide bonds and hydrophobic bonds. After extrusion, during the cooling process, hydrogen bonds in the protein matrix can significantly contribute to further increasing the gel strength (firmness) of the extruded product. It is well known and disclosed by Sun and Arntfield [Reference 4] that low temperatures for storage (e.g., between 0°C and 6°C) and the cooling process after protein gel formation can facilitate the extensive and increasing formation of hydrogen bonds. Additionally, it is also well known that during the cooling process after starch is heated and gelatinized in water, the starch gel strength also mostly and significantly increases because extensive hydrogen bonds are generated between starch molecules during cooling. Starch retrogradation can occur after starch gelatinization. Longer storage time periods can lead to further formation of hydrogen bonds and thus lead to further tightening (firming) of the structure and lower water-holding capacity. Therefore, starch gelatinization and retrogradation are another factor contributing to the problems of firm texture and loss of attractive mouthfeel in meat alternative products produced by high-moisture protein texturization extrusion in the methods known in the background art.

[0078] In the context of baked bread, the adverse effect of retrogradation on crumb texture is well known: retrogradation significantly causes crumb staling and increased firmness during storage time.

[0079] Hydrogen bonds are short-range chemical bonds, which means that the crosslinking associated with hydrogen bonds mainly occurs between adjacent compounds in close or direct contact (e.g., protein-protein, protein-starch, starch-starch). Starch of the amylose type has a high ability to form starch-starch hydrogen bonds because it has many hydroxyl groups and linear polymer chains in its molecular structure. Starch before gelatinization cannot form a gel in water because the starch is embedded in the starch granule structure and is thus insoluble. Starch gelatinization can occur more extensively during high-moisture extrusion than during low-moisture extrusion. During high-moisture protein texturization extrusion, the starch is sufficiently heated and leached into the water by heat and shear forces, causing the leached amylose molecules to be linearly arranged and in close contact with each other.

[0080] Since the extruded products from high moisture protein texturizing extrusion have a relatively high density (less expansion, higher density), and form more excessive hydrogen bond type protein-protein crosslinking forces than those from low moisture extrusion, adding particulates (such as starch powder, insoluble salts, fibers, fats, etc.) can hardly disrupt the protein-protein crosslinking or interactions that occur excessively during the cooling stage and after extrusion as in low moisture extrusion. Therefore, these extruded products with or without added particulates still suffer from problems of structural hardening (rigidity) and loss of acceptable mouthfeel (such as compressibility) during cooling and storage times. More specifically, the particulates are easily homogenized, covered, and emulsified by the protein matrix quickly during extrusion or immediately after the particulates are extruded together with the protein material. Then the particulates cannot provide a large enough disruptive force or a barrier effect between protein fibers, and may only be able to provide a limited disruptive area around each individual particulate point without extension. More severely, when starches are added in the form of starch powder (including or not including modified starch or pregelatinized starch) or cereal flour powder, they are also quickly homogenized, covered, and emulsified by the protein matrix after being extruded together with the protein material. Then, the emulsified starch is heated and gelatinized. Throughout the extrusion process and in the final product, the starch remains as small particulates. So the starch can hardly provide a large disruptive force or a barrier effect between protein fibers, and may only be able to provide a limited disruptive area around each individual particulate point without extension. After extrusion, the protein matrix around the starch particulates can continue to harden, forming protein-protein interactions such as more hydrogen bonds. In addition, after being sheared, gelatinized, distributed within (between) linearly arranged protein fibers, and linearly arranged, the starch becomes extremely susceptible to starch gelatinization, retrogradation, hardening, drying, and possible starch-protein interactions through hydrogen bond formation. Thus, the extruded products suffer from very significant problems of structural hardening (rigidity) and loss of acceptable mouthfeel (such as compressibility) during cooling and storage times.

[0081] II: Processor (extrusion system) for performing the tests described in the following examples Figure 12B Schematically shows an extruder 13 configured to perform a high moisture protein texturizing extrusion process for implementing the method described according to the present invention. The extruder 13 realizes the technical features required for the new process.

[0082] In the new process, mechanically processed starch-containing grains are mixed with starch-containing grains in powder form (preferably cereal flour), at least one (preferably vegetable or dairy) protein isolate / at least one (preferably vegetable or dairy) concentrate / mixtures of at least one such isolate and at least one such concentrate, optional oils and optional spices and any other ingredients in mixer 121 and fed through feed line 122 into extruder 13, for example through inlet funnel 123. Extruder 13 has a liquid feed line 124 connected to a water heating element 14 configured to provide heated water (such that the heated water is significantly above the temperature of tap water, for example having a temperature of at least 50 °C) and preferably configured to provide water with a stable temperature (for this purpose, heating element 14 preferably has a pump 132 and a heater tank 133, and heater tank 133 preferably has a water heating element and a temperature detector). Extruder 13 also includes a long cooling die 125. Pump 132 can be controlled such that the water fed into tank 131 always has the target temperature and pump 130 can feed water into extruder 13 at a target flow rate (e.g., in kilograms of water per hour). If tap water is directly connected to tank 131 and an attempt is made to heat the water in tank 131, it will be more difficult to precisely control the temperature of the water.

[0083] In the following examples, the experiments conducted by the inventors are described in more detail.

[0084] III: First experiment (Examples 1 and 2) Hereinafter, also in the entire description of the composition of the samples in other experiments and tests, the percentages of the components are given in weight % based on a dry basis.

[0085] Using Examples 1 and 2, we demonstrated exemplary parameters of the manufacturing process (composition, impact heating) and their influence on the quality of the resulting meat substitute products (such as in terms of specific physical properties, such as compressibility, hardening, swelling, cavity structure).

[0086] The mechanically processed starch-containing grains comprise one or more of the following or consist of one or more of the following: cereals (such as compressed, rolled or flaked), steel cut grains, dehulled pearled grains, crushed grains, dehulled but unpearled grains.

[0087] The mechanically processed starch-containing grains comprise one or more of the following or consist of one or more of the following: oats, barley, rye, wheat, rice, corn, lentils, chickpeas, mung beans, fava beans, peas, quinoa, pigeon peas, sorghum, buckwheat.

[0088] However, the following components are excluded from the mechanically processed starchy grains: dehulled but unpearled oat grains, dehulled but unpearled rye grains, dehulled but unpearled barley grains, and dehulled but unpearled corn grains.

[0089] Although additional extruder configurations can be used, the extruder 13 used for the experiments is a twin-screw co-rotating extruder having a screw 126 with a diameter between 30 mm and 50 mm. The extruder 13 has a screw chamber 138 around the screw 126. In the configuration used, the screw chamber 138 has 6 zones (although a different number of zones is possible), which can be labeled as zones 1 to 6 starting from the solid component feed to the extruder and the extrusion start side. Thus, there is an inlet hole 139 for feeding the solid component (for example in zone 1). Zones 2, 3, 4, 5, and 6 are each equipped with heating, cooling, and temperature detection elements, which preferably can individually control the temperature of each zone between, for example, 10 °C and 220 °C. In addition, there is an inlet hole 140 (for example in zone 2) for feeding a liquid into the extruder 13 to be extruded together with the solid component.

[0090] At a typical screw rotation speed (for example between 150 rpm and 300 rpm), the material can pass through the screw chamber 138 in about 45 s to 75 s. The inventors set the water feeding to the liquid feed line 124 and the heating element 14 with water at different temperatures between 5 °C and 99 °C. For example, in some cases, heated water is fed into the tank 131, and the heated water is pumped to the extruder 13 by the pump 130 of the liquid feeder. Tests were carried out to stop the extruder and remove the screw after continuously operating the extrusion of dry oatmeal without water. And it was observed that with a screw grinding time of 5 - 15 s (calculated from the conveying distance, for example), in approximately zone 2, most of the oatmeal (more than 90%) was substantially pulverized into particulate grains significantly smaller than their original size (for example, their size was less than 200 μm).

[0091] Alternatively, the conventional liquid feed line 124 is connected to conventional tap water, and tap water between 5 °C and 25 °C is fed into the extruder (as Figure 12A shown). The feeding rates of the solid component and the liquid (for example kg / h) can be controlled separately.

[0092] After the final zone (e.g., zone 6), there is a long cooling die 125 connected to the extruder 13, which also has heating, cooling, and temperature detection elements. The long cooling die 125 is longer than 300 mm, preferably with a length between 300 mm and 5000 mm, and most preferably between 1000 mm and 3000 mm. Between the final zone (e.g., zone 6) and the cooling die 125, there are pressure detection sensors and temperature detection sensors. In addition, a cutting tool can be connected after the long cooling die 125.

[0093] Those skilled in the art have sufficient knowledge from the background art to know how to adjust or select the diameter of the screw 126, the speed of the screw 126, the length and shape of the cooling die 125, the type of cutting tool, and the cutting speed according to different types of customized requirements such as production stability, production speed, product size and shape.

[0094] Example 1 (Samples No. 1, No. 2, No. 3, No. 4) - Influence of Composition on the Textural Properties of Extruded Products The inventors prepared 4 samples (No. 1, No. 2, No. 3, No. 4), which were processed by high-moisture protein texturization extrusion using the extruder 13 shown in Figure 12B ...

[0095] Sample No. 1 contains 90 wt% pea protein, 5 wt% oat flour, 4 wt% fiber, and other ingredients are also added (such as salt, spices, yeast extract, oil, oat malt extract, starch-free grains - e.g., sunflower seeds).

[0096] Sample No. 2 contains 90 wt% pea protein, 5 wt% steel-cut oats, 4 wt% fiber, and other ingredients are also added (such as salt, spices, yeast extract, oil, oat malt extract, starch-free grains - e.g., sunflower seeds).

[0097] Sample No. 3 contains 62 wt% pea protein, 20 wt% oat flour, 10 wt% fiber, and other ingredients are also added (such as salt, spices, yeast extract, oil, oat malt extract, starch-free grains - e.g., sunflower seeds).

[0098] Sample No. 4 contains 62 wt% pea protein, 1 wt% steel-cut oats, 19 wt% oat flour, 10 wt% fiber, and other ingredients are also added (such as salt, spices, yeast extract, oil, oat malt extract, starch-free grains - e.g., sunflower seeds).

[0099] After production, Samples No. 1, No. 2, No. 3, and No. 4 were cooled and stored overnight. The next day, their mechanical properties were measured to study the texture. The measurement results are shown in Table II.

[0100] The results in Table II show that Samples 1 and 3 produced from the composition containing the starchy flour (oat flour) have a hard and rubbery texture and high resistance to cylindrical compression.

[0101] The results in Table II also show that Samples 2 and 4, in which the starchy flour (oat flour) is replaced or partially replaced by starchy grains (steel-cut oats), are more flexible and compressible than Samples 1 and 3.

[0102] After steaming in water in a pressure cooker (such as in a pressure pan) at 110 °C, Sample 2 has a much higher thickness steaming expansion rate (265%) than Sample 1 (143%). This difference is caused only by the change in the starchy component (from flour to steel-cut grains). Other conditions such as extrusion parameters are kept the same; and the composition has the same chemical (nutrient) composition.

[0103] Table II. Texture of Samples 1, 2, 3, and 4 · As the protein in Example 1, we use pea protein isolate. It can be at least partially replaced by pea protein concentrate, or replaced by any other protein isolate or protein concentrate (such as broad bean, soybean, chickpea, wheat gluten, oats), dairy (milk or whey) protein, or a mixture of at least one of these. The results are comparable.

[0104] · The grains used in Example 1 are steel-cut oats. It can be replaced by the mechanically processed starchy grains described above (note the excluded types above), in particular by steel-cut barley, rice grains, broken rice, pearled barley, pearled rye, pearled wheat, pearled oats, (for example, pea crushed seeds with a particle size of 2 mm), broad bean crushed seeds, chickpea crushed seeds, lentil seeds, etc. and mixtures thereof. The results are comparable.

[0105] · In this example, the mechanically processed starchy grains are immersed in hot water before extrusion. The immersion is carried out by gently mixing the grains with hot water (such as 90 °C) at a ratio of 1:2, and then keeping them at a warm temperature (such as 75 °C) for 2 hours. After immersion, the grains absorb all the water and become softer and larger.

[0106] · The flour in Example 1 is oat flour. It can be replaced by barley flour, wheat flour, rice flour, pea flour, chickpea flour, broad bean flour, lentil flour, etc. and mixtures thereof. The results are comparable.

[0107] · The fiber in Example 1 is pea fiber. It can be replaced by oat fiber, oat bran, potato fiber, broad bean fiber, etc. and mixtures thereof. The results are comparable.

[0108] · The other ingredients in Example 1 include all of the following: salts, spices, yeast extracts, oils, oat malt extracts, starch-free grains (such as sunflower seeds), and so on. Some of these can be omitted or replaced with other desired ingredients.

[0109] · Measure the resistance to cutting with a sharp blade as the cutting force in Example 1. The measurement is carried out using the texture analyzer described above.

[0110] · Measure the resistance to compression with a cylinder as the compression force in Example 1. The measurement is carried out using the texture analyzer described above.

[0111] · As the texture observation in Example 1 in Table II, the texture property observation records are analyzed by a panel of experts conducting sensory evaluations.

[0112] The extrusion parameters used in Example 1: (1) Liquid feed: hot water (e.g., having a raised temperature of 65 °C); (2) The moisture content of the slurry (the material being extruded) during extrusion is approximately 50%. Depending on the desired properties of the extruded product (such as moisture content, color, etc.) and changes in the composition (e.g., different proteins may have different melting requirements, different starches may have different gelatinization requirements), the moisture content of the slurry can be adjusted between 40% and 80%; (3) Extruder heating profile: an impact heating profile with temperatures of 80 - 125 - 160 - 145 - 130 (°C) in zones 2 - 3 - 4 - 5 - 6. The cooling die temperature is 90 °C. Depending on changes in the composition (e.g., different proteins may have different melting temperatures, different starches may have different gelatinization temperatures), the temperature can be adjusted within the range described in the method item; (4) Productivity: approximately 18 kg of product is manufactured per hour. The pressure at the end of the screw: between 1.0 mPa and 3.0 mPa.

[0113] (5) Immediately after extrusion, the extruded product is immersed in water (e.g., 20 °C) for 2 hours to cool and prevent drying. Then it is taken out of the water. Then, after storing in a cold room (e.g., 5 °C) for 24 hours, the cutting force, compression force, texture observation, and thickness cooking expansion rate of the sample are analyzed.

[0114] N.A represents not analyzed.

[0115] The expansion in Example 1 represents the thickness cooking expansion rate analyzed by the cooking test method, which will be described below. Unless otherwise stated, such as "extrusion expansion rate", throughout this application, "expansion" or "expansion rate" always refers to the thickness cooking expansion rate.

[0116] In further experiments, the composition of Sample 1 (90 wt% pea protein + 5 wt% oat flour + 4 wt% fiber, with other ingredients added) was processed with different extrusion parameters. Different extrusion parameters such as different liquid feed water temperatures (15°C - 90°C), extrusion machine heating profiles ("impact heating" such as (in zones 2 - 3 - 4 - 5 - 6) 80 - 125 - 160 - 145 - 130°C), "overheating" such as 80 - 125 - 160 - 160 - 160°C, "slow heating" such as 40 - 75 - 100 - 140 - 165°C, all produced unacceptable products (similar to Sample 1) which had a hard and rubbery structure and texture, with cutting forces between 500 g and 1100 g, compression forces between 18,200 g and 44,000 g, and cooking expansion rates between 125% and 149%. The results from these experiments were not satisfactory. The texture was completely incomparable to cooked chicken drumsticks.

[0117] Replacing the oat flour with other starchy flours such as oat starch, potato starch, rice starch, chickpea starch, wheat starch, pea starch, etc. also produced unacceptable results similar to Sample 1. The inventors conducted a large number of tests.

[0118] Replacing the oat flour with non - starchy grains such as sunflower seeds, peanut flakes, almond seed flakes, coconut microparticles, chia seeds also produced unacceptable products similar to Sample 1.

[0119] Replacing the oat flour with starchy grains having a complete husk or a complete, thick, and firm seed coat (also known as the pericarp layer, bran layer) or a complete outer skin such as whole - grain oat seeds, whole - grain barley seeds, whole - grain rye seeds also produced unacceptable products similar to Sample 1.

[0120] However, adding these microparticles (such as sunflower seeds, chia seeds, whole - grain oat seeds) between 0% and 20% (preferably between 0% and 10%) to the composition to partially replace the protein in an acceptable sample such as Sample 2 did not have an adverse effect on the quality of the extruded product.

[0121] Adding additives such as calcium chloride, calcium carbonate, gypsum powder (calcium sulfate dihydrate), baking powder, psyllium, alginate, ascorbic acid, xanthan gum, agar - agar, etc. to the composition of Sample 1 did not produce the desired properties observed in acceptable samples such as Sample 2.

[0122] However, it is still possible to add some of these additives (such as baking powder, gypsum powder, ascorbic acid) between 0% and 5% to the other components of an acceptable sample such as Sample 2, because it will not cause a serious adverse effect on the quality (compression characteristics and taste) of the extruded product.

[0123] Example 2 (Samples 5, 6, 7, 8, 9) - Influence of extrusion composition and extrusion heating profile on the texture and expansion properties of extruded products.

[0124] The inventors prepared 5 samples (Samples 5, 6, 7, 8, 9), which were processed by high-moisture protein texturizing extrusion using the extruder 13 shown in Figure 12B Samples 5 contained 70% by weight of pea protein and 30% by weight of oat flour.

[0125] Similar to Sample 5, Sample 6 contained 70% by weight of pea protein and 30% by weight of oat flour.

[0126] Sample 7 contained 70% by weight of pea protein, 10% by weight of rolled oats, and 20% by weight of oat flour.

[0127] Similar to Sample 7, Sample 8 contained 70% by weight of pea protein, 10% by weight of rolled oats, and 20% by weight of oat flour.

[0128] Sample 9 contained 70% by weight of pea protein, 20% by weight of rolled oats, and 10% by weight of oat flour.

[0129] After production, Samples 5, 6, 7, 8, and 9 were cooled and stored overnight. Their mechanical properties were measured the next day to study the texture. The measurement results are shown in Table III.

[0130] Table III. Texture of Samples 5, 6, 7, 8, and 9

[0131] Table III shows that Samples 8 and 9 of the extruded products containing rolled oats produced by extrusion with an impact heating temperature profile (hot water liquid feed used together with the temperature profile of 80 - 125 - 160 - 145 - 130 °C in the 2 - 3 - 4 - 5 - 6 zones) have a more flexible and compressible texture, which produces a very good taste and is pleasant to eat. After steaming in water, it also has a high steaming expansion rate (189% - 206%), which is consistent with its property of having a flexible and extensible structure and texture.

[0132] ​When the oatmeal was completely replaced with oat flour having the same chemical composition but much smaller particle size (Sample No. 6), the extruded product became hard, rubbery and had a lower cooking expansion ratio (129%). The taste was completely incomparable with that of cooked chicken drumsticks. The impact heating extrusion conditions did not result in large differences between the products without oatmeal (between Sample No. 5 and Sample No. 6).

[0133] When oatmeal was used under extrusion conditions without impact heating setting (for example, if the liquid feed water temperature was 25°C and the temperature setting of Zone 2 was 40°C), the product (Sample No. 7) had a hard and rubbery texture and a low expansion ratio (164%). The taste was completely incomparable with that of cooked chicken drumsticks.

[0134] · The protein in Example 2 was pea protein isolate. It could be replaced with other proteins in the manner described in the context of Example 1.

[0135] · Oatmeal was used as the mechanically processed starchy grain in Example 2. Oatmeal could be replaced with other mechanically processed starchy grains in the manner described above and in the context of Example 1. In particular, flaked barley, steel-cut oats, steel-cut barley, rice grains, broken rice, pearled barley, pearled rye, pearled wheat, etc. and mixtures thereof could be used. The results were comparable.

[0136] · In Example 2, the mechanically processed starchy grain was not immersed in hot water before extrusion.

[0137] · The flour in Example 2 was oat flour. It could be replaced with barley flour, wheat flour, rice flour, pea flour, chickpea flour, fava bean flour, quinoa, pigeon pea, sorghum, buckwheat, etc. or mixtures thereof. The results were comparable.

[0138] · The expansion in Example 2 represented the thickness cooking expansion ratio analyzed by the cooking test method, which will be described below.

[0139] · The visible air cavities in Example 2 represented the visible air cavities in the extruded product analyzed by the visual inspection method, which will be described below.

[0140] · The texture observation in Example 2 represented the record of the texture property observations generated by the sensory evaluation of the panel.

[0141] · Extrusion parameters: (1) The moisture content of the slurry (the material being extruded) during extrusion was about 50%; (2) Immediately immerse the extruded product in water (20 °C) for 2 hours after extrusion to cool and prevent drying. Then take them out of the water. Then, after storing them in a cold room (e.g., 5 °C) for 24 hours, analyze the texture observation, visible air cavities, and thickness cooking expansion rate of the samples.

[0142] (3) Productivity: Approximately 18 kg of product is manufactured per hour. The cooling die temperature is 90 °C.

[0143] Examples of air cavities can be seen in Figure 1 and Sample No. 8 in Figure 2.

[0144] IV: Results of the First Experiment Figure 1 These are photos of Samples No. 5, No. 7, and No. 8 (from bottom to top) taken after soaking in water at 60 °C for 24 hours: On the right, the samples are cut parallel to the fiber direction so that the fibers, length, and thickness of the samples are visible. On the left, the samples are cut across the fiber direction so that the cross-section (width and thickness) of the samples is visible. Sample No. 8 has significantly more visible air cavities than Samples No. 7 and No. 5. The air bubbles in Sample No. 8 are more evenly distributed in the protein fiber matrix, with a larger total volume and larger average size than the air bubbles in Samples No. 5 and No. 7. Figure 1 There are white particles in Sample No. 7 of Figure 1 , which include intact oatmeal particles within the protein matrix. The included particles do not solve the problem of the product being rubbery, hard, and difficult to compress. The visible particles are not pulverized by the extruder, mainly due to the fact that some very small portions (e.g., less than 5%) of the particles slip through the narrow gap between the screw and the screw chamber. They remain mostly intact throughout the extrusion and do not mix effectively with other ingredients. The degree of gelatinization of these particles is insufficient and much lower than that of other particles effectively mixed by the screw (e.g., those pulverized in Sample No. 7). At the end of the process, they are covered by other materials. They cannot disrupt the overall formation of the protein fiber structure or the growth of the inter-fiber interaction forces. These are consistent with the

[0145] Figure 2A These are X-ray microtomography (Micro-CT) scan images of Sample No. 5 taken after soaking in water at 60 °C for 24 hours and air drying. The sample is cut parallel to the fiber direction so that the fibers, length, and thickness of the sample are visible.

[0146] Figure 2B These are X-ray microtomography (Micro-CT) scan images of Sample No. 8 taken after soaking in water at 60 °C for 24 hours and air drying. At Figure 2AThe samples were cut in the same manner. Figure 2A and Figure 2B The difference between the two is clear, and it can be seen that sample No. 8 has more air bubbles (black cavities between white fibers), which are widely and evenly distributed in the protein fiber matrix, with a larger total volume and a larger average size than sample No. 5. In addition, sample No. 8 obviously has a long continuous fiber structure. The fibers of sample No. 8 are thinner and have a more uniform thickness than the fibers of sample No. 5. Most of the fibers are parallel to each other. This shows that although protein fibers tend to stick to each other and form larger bundles or groups, the protein fibers are well broken and separated in sample No. 8. The thinner fiber structure of sample No. 8 contributes to a good, chewy and compressible texture, which is close to the chicken thigh meat of steaming. The aggregation and layered structure of sample No. 5 makes it have an unfavorable, hard, leather-like and rubber-like texture.

[0147] Figure 6A is a microscope image of a sample taken from sample number 2. The sample was stained with a protein dye (Thermo Scientific Pierce Coomassie Brilliant Blue R-250). The sample was observed using an optical microscope (Zeiss Axio Lab.A1 laboratory microscope) at 10x magnification. The protein fibers are stained black. The protein fibers are continuous throughout the image and are much larger than 1 mm in length. The protein fibers are mostly arranged parallel to each other. Crosslinking is low, with only a few connections between adjacent fibers.

[0148] Figure 6B is a microscope image of a sample taken from sample No. 2. The sample was stained with a dilute iodine solution, such as a 1:5 diluted Sigma-Aldrich Lugol's solution stabilized with polyvinyl pyrrolidone for Gram staining. The sample was observed with an optical microscope at 10X magnification. The dark black material (lumps) indicated starch-rich material, which formed a dark blue iodine-starch complex with the iodine stain. Figure 6B The protein fiber matrix is ​​also shown in gray, which is lighter in color than the starch material and more transparent than the starch material, but not completely transparent. The starch-rich material appears rounded or random in shape, is not tightly embedded in the protein fiber matrix, and is not evenly distributed throughout the structure. These findings indicate that the starch is in the form of clusters, a phase separated from the protein phase, and is not emulsified by the protein.

[0149] Figure 6C is a microscope image of a sample taken from sample No. 2. Figure 6A The samples were stained with a protein dye in and observed at 20x magnification. The protein fibers were mostly arranged parallel to each other. The cross-linking was low, with only a few connections between adjacent fibers.

[0150] Figure 6Dis a microscope image of a sample taken from sample No. 2. The sample was stained with a dilute iodine solution, such as 1:5 diluted Sigma-Aldrich Lugol's solution stabilized with polyvinyl pyrrolidone for Gram staining, and observed at 20X magnification. The dark black material (lumps) indicate starch-rich material, which forms a dark blue iodine-starch complex with the iodine stain. Figure 6D The protein fiber matrix is ​​also shown in gray, which is lighter in color than the starch material, more transparent than the starch material, but not completely transparent. The starch-rich material presents a round or random shape, is not tightly embedded in the protein fiber matrix, and is not evenly distributed throughout the structure. These findings indicate that starch is in the form of clusters, is a phase separated from the protein phase, and is not emulsified by protein. There are starch clusters (shown as dark spots) greater than 30 μm in size (e.g., length).

[0151] Figure 6E is a microscope image of a sample taken from sample number 6. The sample was stained with a protein dye such as Thermo Scientific Pierce Coomassie Brilliant Blue R-250 and viewed at 10x magnification. The protein fibers are stained black. The protein fibers are continuous throughout the image and are much larger than 1 mm in length. The protein fibers are mostly aligned parallel to each other. Cross-linking is high: Figure 6E The connections between adjacent fibers are significantly Figure 6A The richer in. Figure 6E The interstitial space between adjacent fibers is significantly larger than Figure 6A There are two rows of bright white spaces between the three protein fibers. They are the empty spaces between two protein fibers.

[0152] Figure 6F is a microscope image of a sample taken from sample No. 6. The sample was stained with a dilute iodine solution, such as 1:5 diluted Sigma-Aldrich Lugol's solution stabilized with polyvinyl pyrrolidone for Gram staining, and observed at a magnification of 10. The dark black material (lumps) indicate starch-rich material, which forms a dark blue iodine-starch complex with the iodine stain. Figure 6F The protein fiber matrix is ​​also shown in gray, which is lighter in color than the starch material, more transparent than the starch material, but not completely transparent. The starch-rich material is in a narrow linear shape and is tightly embedded in the protein fiber matrix, and is obviously substantially evenly distributed between and along the entire structure of the protein fibers, and the distribution, shape and distribution of the starch-rich material are highly ordered. These indicate that the starch is emulsified by the protein.

[0153] Figure 6Gis a microscope image of a sample taken from sample number 6. The sample was stained with a protein dye such as Thermo Scientific Pierce Coomassie Brilliant Blue R-250 and viewed at 20x magnification. The protein fibers are stained black. The protein fibers are mostly arranged parallel to each other. Cross-linking is high: Figure 6G The connections between adjacent fibers are significantly Figure 6C The richer in. Figure 6G The interstitial space between adjacent fibers is significantly larger than Figure 6C The one in is narrower and smaller.

[0154] Figure 6H is a microscope image of a sample taken from sample No. 6. The sample was stained with a dilute iodine solution, such as 1:5 diluted Sigma-Aldrich Lugol's solution stabilized with polyvinyl pyrrolidone for Gram staining, and viewed at 20X magnification. The dark black material (lumps) indicate starch-rich material, which forms a dark blue iodine-starch complex with the iodine stain. Figure 6H The protein fiber matrix is ​​also shown in gray, which is lighter in color than the starch material, more transparent than the starch material, but not completely transparent. The starch-rich material presents a narrow linear shape, is tightly embedded in the protein fiber matrix, and is obviously evenly distributed between the protein fibers and along the entire structure of the protein fibers. The distribution, shape and distribution of the starch-rich material are highly ordered. These indicate that the starch is emulsified by protein.

[0155] Figure 7A is a microscope image of a sample of washable starch taken from sample No. 2 washed with water at 50°C. Figure 7A Insoluble washable starch (black material in the image) in the form of clusters is shown, with sizes ranging from 50 μm to 800 μm. Each cluster contains more than 5 individual starch granules (circles) therein. Within each cluster, the individual starch granules are tightly bonded to each other. The samples were observed under an optical microscope at a magnification of 5 times.

[0156] Figure 7B is a microscope image of a sample of washable starch taken from sample No. 2 washed with water at 50°C. Figure 7B Insoluble washable starch (black material in the image) is shown to be present in the form of clusters, approximately 100 μm in size. Each cluster contains more than 5 individual starch granules (circles) therein. Within each cluster, the individual starch granules are tightly bonded to each other. There is starch leaching out of the clusters of aggregated starch granules into the water. This leached starch allows these clusters to be "washed" by 50°C water. Those starches embedded in such clusters are insoluble in 50°C water, but soluble in 110°C water. The samples were observed under an optical microscope at a magnification of 20 times.

[0157] Figure 10The gelation of pea protein affected by heating temperature is shown. To see how heating temperature can affect the gelation of pea protein, pea protein was mixed with water at a ratio of 1:1, then packaged into a vacuum bag, and then heated at different temperatures (from 50 °C to 110 °C). Then the texture of the gel / block was measured. As can be seen from the results in the table, the samples heated to 90 °C and above significantly had higher hardness. These indicate that when heated to 90 °C or above, a significantly firmer gel was formed.

[0158] Figure 14A The starch coating on the inner surface of the cavity of the extruded product observed by iodine staining and visual inspection is shown. Left: A section of sample No. 2. Right: A section of a sample produced under similar conditions to sample No. 2, but using whole oat grains that were dehulled but not pearled to replace the steel-cut oats used in sample No. 2. The right sample had an unacceptable texture: for example, the compression force exceeded 20,000 g.

[0159] Two samples were cut into slices approximately 1 mm thick, approximately 10 mm wide, and 40 mm long. The direction of the length was mainly parallel to the direction of fiber orientation. One slice of each sample was stained with a diluted Lugol's solution (iodine solution for staining) for 45 minutes. The amount of the diluted Lugol's solution was between 1 mL and 3 mL and could cover the sample in all directions. Then the stained sample was gently moved and immersed in 50 ml of water for 5 minutes. Then we placed the slice on white paper for visual observation.

[0160] Figure 14A The grey blocks in the photos refer to the overall structure (protein matrix structure and all other materials embedded in the protein matrix structure). The dark color (black) indicates materials enriched in starch content.

[0161] The section of sample No. 2 (i.e., the left side) had a significantly dark coating material on the inner wall as well as the outer wall (surface) of the cavity of the extruded product.

[0162] The section of the other sample (i.e., the right side) had dark colors in the form of large dots (such as 1-mm dots) within the structure. The dark dots should be unbroken oat seeds. The sample contained visible unbroken seeds as inclusion particles, but it had an unacceptable texture.

[0163] No significantly dark coating material was found in No. 1, No. 3, No. 5, No. 6, and No. 7.

[0164] Figure 14BThe inner surface of the cavity of the extruded product examined by iodine staining and microscopy (5x magnification, using a stereomicroscope, such as a Zeiss Stemi 305 stereomicroscope) is shown. The sample was taken from Sample No. 2. The sample was stained with a diluted Lugol's solution (iodine solution for staining) for 30 minutes before observation. The gray blocks in the photo refer to the overall structure (protein matrix structure and all other materials embedded in the protein matrix structure). The dark (black) color indicates materials enriched in starch content. When observed via microscopy, the color view is blue or dark blue or black.

[0165] Figure 14C The inner surface of the cavity of the extruded product observed by iodine staining with a 20x magnification microscope is shown. The sample was taken from Sample No. 2. The sample was stained with a diluted Lugol's solution (iodine solution for staining) for 30 minutes before observation. The dark gray blocks with a specific fibrous (anisotropic) structure in the figure (from the left to the middle of the picture) refer to the overall structure (protein matrix structure and all other structures embedded in the protein matrix). There are clusters of black dots at the left side of the picture, indicating clusters of gelatinized starch. The light gray blocks adjacent to the very bright white and blank areas (on the right side of the picture) indicate materials enriched in starch content. Since the wall is more directly exposed to the microscope light, the starch at the cavity wall observed at this magnification and angle has a lighter color than the protein matrix structure. When observed via microscopy, the starch at the cavity wall observed at this magnification and angle is light blue.

[0166] Figure 14D and Figure 14E The inner surface of the cavity of the extruded product examined by iodine staining and microscopy (40x magnification) is shown. The sample was taken from Sample No. 2. The sample was stained with a diluted Lugol's solution for 30 minutes before observation. The dark gray blocks with a specific fibrous (anisotropic) structure in the figure refer to the overall structure (protein matrix structure and all other structures embedded in the protein matrix). The light gray blocks without a fibrous structure adjacent to the very bright white and blank areas (in the middle of the picture) indicate materials enriched in starch content. The starch at the cavity wall observed at this magnification and angle has a lighter color than the protein matrix structure. When observed via microscopy, the starch at the cavity wall observed at this magnification and angle is light blue.

[0167] Figure 15 are photos of Sample No. 2 (reference numeral 1) before (top photo) and after (bottom two photos, reference numeral 2) expansion by steaming in water in a pressure cooker at 110 °C for 10 minutes.

[0168] V: Further experiments (Examples 3 and 4) Using Examples 3 and 4, we further demonstrate the exemplary parameters of the manufacturing process (impact heating) and their impact on the quality of the resulting meat alternative products (such as in terms of specific physical properties, such as compressibility, hardening, expansion, cavity structure).

[0169] Example 3 (Samples 10, 11, 12, 13) - Hardening and compressibility of extruded products affected by the extrusion temperature setting Samples 10, 11, 12, and 13 contain 70 wt% pea protein, 5 wt% steel-cut oats, 24 wt% oat flour, and 1 wt% salt. Samples 10, 11, 12, and 13 were each processed in an extruder 13 with different extrusion temperature settings.

[0170] Table IV shows that when using mechanically processed starch-containing grains (such as steel-cut oats) in the composition, the impact heating temperature setting of the extrusion conditions results in good compressibility (compression force 10 234 g) and moderate hardening (129%) of the produced product (Sample 13).

[0171] However, when the liquid feed water temperature is low (such as 25°C commonly used in known extruder 12), and / or when the temperature in the extruder does not use an impact heating profile (zone 2 temperature below 100°C, and / or zone 4 temperature below 160°C), the products so produced (Samples 10, 11, 12) have more severe hardening problems (186% - 232%) and poor compressibility (compression force 17 803 g – 20 844 g). Although they have a lower hardness when fresh (5 minutes after extrusion) (lower than Sample 13), they have a much higher hardness after 5 hours of storage (higher than Sample 13).

[0172] Table IV. Texture of Samples 10, 11, 12, 13 · The protein in Example 3 is pea protein isolate. It can be replaced with other proteins in the manner described in the context of Example 1.

[0173] · Steel-cut oats were used as the mechanically processed starch-containing grain in Example 3. Oat flour was used as the flour. Steel-cut oats and oats can be replaced with other mechanically processed starch-containing grains and flours in the manner described above and in the context of Example 1.

[0174] · In particular, steel-cut oats can be replaced by steel-cut barley, rice grains, broken rice, pearled barley, pearled rye, pearled wheat, pearled oats, etc., or mixtures thereof. The results are comparable. Oat flour can be replaced by barley flour, wheat flour, rice flour, pea flour, chickpea flour, broad bean flour, quinoa, pigeon pea, sorghum, buckwheat, etc., and mixtures thereof. The results are comparable.

[0175] · In this embodiment, the steel-cut oats are not immersed in hot water before extrusion.

[0176] · Extrusion parameters: (1) The moisture content of the slurry (the material being extruded) during extrusion is about 50%; (2) Some of the extruded products are immediately immersed in water (e.g., 20 °C) for 2 hours after extrusion to cool and prevent drying. Then they are taken out of the water. After storing at 5 °C for 24 hours, their compressive force is analyzed; (3) Some of the extruded products are immediately packaged in a closed plastic bag to prevent drying, stored at room temperature, and their hardness and hardening are analyzed; (4) Extrusion productivity: Approximately 18 kg of product is manufactured per hour. The cooling die temperature is 90 °C.

[0177] · The compressive force in Example 3 represents the resistance to cylindrical compression analyzed by the texture analysis method described above.

[0178] · The texture observation in this embodiment represents the record of the texture property observations analyzed by the sensory evaluation of a panel of experts.

[0179] · The hardness in this embodiment represents the hardness of the unsoaked extruded product analyzed by a texture analyzer using the cylindrical compression method to be described below.

[0180] · Hardening refers to the hardening rate after 5 hours of storage, which can be calculated as: Hardening rate = 100% x hardness (5 hours) / hardness (5 minutes).

[0181] Example 4 (Samples No. 14, 15, 16, 17) - Structure and compressibility of extruded products affected by extrusion temperature setting The components used for Samples No. 14, 15, 16, and 17 are: 90 wt% pea protein isolate, 5 wt% steel-cut oats, 4 wt% pea fiber, and 1 wt% salt.

[0182] Table V shows that when mechanically processed starch-containing grains (now: steel-cut oats) are used in the composition, the functional combination of (a) using an extrusion impact heating temperature setting and (b) using hot water as the liquid feed for Sample No. 16 results in good compressibility of the resulting product (compression force 16,290 g).

[0183] When the extrusion temperature becomes a slower heating profile (temperature decreases in Zone 4 to 130 °C; and temperature increases in Zone 6 to 160 °C), the resulting product (Sample No. 15) has much poorer compressibility (26,484 g).

[0184] When the extrusion heating temperature becomes an "excessive" heating profile as in the production of Sample No. 17, where the temperatures in Zones 5 and 6 increase (160 °C and 160 °C), the resulting product (Sample No. 17) no longer has the desired continuous or intact structure. So its compression force is not measurable. And the product does not have the ideal chewiness similar to Sample No. 16. These make it impossible to produce meat substitute products similar to chicken legs or chicken nuggets from Sample No. 17.

[0185] When the extrusion temperature becomes a "very slow" heating profile as in the production of Sample No. 14, where the temperature in Zone 2 is below 80 °C, the temperature in Zone 4 is below 160 °C, and the liquid feed water is cold (25 °C), the resulting product (Sample No. 14) no longer has the desired continuous or intact structure. So the compression force is not measurable. And the product does not have the ideal chewiness similar to Sample No. 16. These make it impossible to produce meat substitute products similar to chicken legs or chicken nuggets from Sample No. 14.

[0186] Table V. Texture of Samples No. 14, 15, 16, and 17 · The protein in Example 4 is pea protein isolate. It can be replaced with other proteins in the manner described in the context of Example 1. The results will be comparable.

[0187] · For the possibility of substituting steel-cut oats and oat flour, apply the same considerations as in Example 3.

[0188] · In Example 4, the steel-cut oats are not immersed in hot water before extrusion.

[0189] · Extrusion parameters: (1) The moisture content of the slurry (the material being extruded) during extrusion is about 50%; (2) The extruded products are immediately immersed in water (e.g., 20 °C) for 2 hours to cool and prevent drying. Then they are taken out of the water. After storing them at 5 °C for 24 hours, their compression force is analyzed; (3) Extrusion productivity: Approximately 18 kg of product is manufactured per hour. The cooling die temperature is 90 °C.

[0190] · In this example, the compression force represents the resistance to cylindrical compression analyzed by the texture analysis method described above.

[0191] VI - Advanced Experiments (Examples 5 and 6) Using Examples 5 and 6, we demonstrated the effects of extrusion conditions and composition on the formation of cavities with gelatinized starch coatings, which are closer to the mechanism of how these processing methods can lead to quality improvement. Some of the samples used in Examples 5 and 6 are the same as those in Example 1.

[0192] Example 5. Starch washable with warm water and starch soluble in warm water from the extruded product affected by extrusion conditions Table VI shows that when steel - cut oats are used in the composition, the functionality of Sample No. 13 combines (a) using the extrusion impact heating temperature setting and (b) using hot water as the liquid feed, resulting in an increase in starch solubility.

[0193] The presence of soluble starch in the extruded product is caused by the combined effect of (a) mixing the grains with water and (b) heating the grains with water early enough before the starch in the grains is emulsified by the protein matrix.

[0194] During extrusion, soluble starch can cause phase separation between protein gels and protein fibers, preventing the formation of a strong fully isotropic (three - dimensional) cross - linked network structure. Soluble starch also forms a coating material between the gaps of the protein matrix, and the gaps will later become cavities inside the extruded product. The coating material strengthens the cavities and prevents them from being sealed by protein cross - links.

[0195] Table VI. · The composition and extrusion parameters used in this example are the same as those described in Example 3. · The total starch in Example 5 represents the total amount of starch in the extruded product, which can be analyzed by any standard starch analysis method or by the hot - water extraction method. The hot - water analysis method is described below.

[0196] · The washable starch in Example 5 (g of washable starch per 100 g of product) represents the amount of starch that can be washed out from the cut slices of the extruded product by 50 °C water, which is analyzed by the water - washing test. This analysis method is described separately in another paragraph. Figure 7A and Figure 7B There are microscopic images of the washable starch.

[0197] · In Example 5, the soluble starch (g of soluble starch in 100 g of product) represents the amount of starch that can be dissolved from the cut slices of the extruded product into water at 50 °C, which is analyzed by the water solubility test. This analysis method is described separately in another paragraph.

[0198] · In this example, the starch solubility represents the ratio between the soluble starch and the total starch. Starch solubility = 100% x soluble starch / total starch.

[0199] Example 6. Starch washable from the extruded product by warm water and starch soluble in warm water affected by ingredients Table VII shows that using oat groats (Sample No. 1) in the ingredients results in a very low starch solubility (3.4%) and little washable starch (0.08 g / 100 g) of the extruded product. However, when the oat groats are replaced with steel-cut oats having the same chemical composition but larger size, the resulting product (Sample No. 2) has a much higher starch solubility (8.4%) and more washable starch (0.41 g / 100 g).

[0200] As Figure 3 shown, and as shown in Example 1, Sample No. 2 has a more flexible and compressible texture than Sample No. 1. This is attributed to the higher amounts of soluble starch and washable starch. This is consistent with the results of Example 5.

[0201] Table VII. Analysis of washable starch and soluble starch · The ingredients and extrusion parameters used in this example: are the same as those described in Example 1.

[0202] · The washable starch (g of soluble starch in 100 g of product) in Example 6 represents the amount of starch that can be washed out from the cut slices of the extruded product by water at 50 °C.

[0203] · The starch solubility in Example 6 represents "the ratio between the soluble starch and the total starch".

[0204] Figure 3 A mathematical model is shown, where an exponential curve is fitted to the measured values. It shows that there is a relationship between the starch solubility and the compression force required to compress meat alternative products manufactured by high moisture protein texturization extrusion.

[0205] VII: Manufacturing Examples (Examples 8 and 9) Example 7 - Manufacturing a meat alternative product in the form of (preferably vegan) thick chunks A meat alternative product in the form of (preferably vegan) thick chunks (imitating chicken thick chunks) is produced by the following steps. Figure 8The results are shown in the example of a food made from a meat alternative product (Sample No. 2) by shredding it into pieces with dimensions of more than 5 cm in length, 1 cm in width, and 0.8 cm in thickness, marinating the pieces, and frying them in a pan. The food mimics a thick piece or slice of chicken leg meat.

[0206] Step 1) Produce a meat alternative product, such as Sample No. 2 or Sample No. 13.

[0207] Step 2) Tear the extruded product into slender strips (e.g., about 2 cm - 4 cm long, 1 cm - 3 cm wide, 0.8 cm thick) so that the fiber direction is along the length direction. Tearing can be done manually or by a shredding machine.

[0208] Step 3) Immerse the torn / shredded extruded product in a marinating sauce (e.g., containing water, oil, lemon juice, balsamic vinegar, sugar, salt, and other spices) for a suitable time (e.g., 2 hours), preferably immediately after extrusion.

[0209] Step 4) Take the extruded product out of the marinating sauce and preferably fry it in a pan for 2 to 3 minutes until it is warmed up and the surface turns golden and crispy.

[0210] After Step 3), the extruded product can be frozen or cooled. Step 4) can be carried out just before eating, such as at home or at work, or in a restaurant after purchasing the product.

[0211] Example 8 - Manufacture of a meat alternative product in the form of (preferably vegan) nuggets Figure 9 Shown are example foods made from a meat alternative product (such as Sample No. 2 or Sample No. 13) after shredding the extruded product into pieces with dimensions preferably more than 3 cm in length, 2 cm in width, and 0.8 cm in thickness, marinating the pieces (left), battering the extruded product, breading the extruded product, and deep - frying it in oil (right). The food mimics chicken nuggets.

[0212] A meat alternative product in the form of (preferably vegan) nuggets can be produced by the following steps: Step 1) Produce a meat alternative product, such as Sample No. 2 or Sample No. 13. Immerse the extruded product in water or a marinating sauce (e.g., containing water, oil, lemon juice, balsamic vinegar, sugar, salt, and other spices) for a suitable time (e.g., 24 hours) after extrusion; Step 2) Cut the soaked extruded product into dimensions and shapes similar to conventional or typical commercial nuggets (e.g., at least 3 cm long, 2 cm wide, 0.8 cm thick).

[0213] Step 3) Prepare a batter by mixing ingredients, such as a formulation of 40% by weight of chickpea flour and 60% by weight of water; Step 4) Cover the cut extruded product with batter. Step 5) Cover the battered extruded product with a breading ingredient (such as a commercial wheat-based frying breading ingredient), breadcrumbs, or with a commercial gluten-free breadcrumb ingredient. Step 6) Deep-fry the breaded extruded product in oil, for example at 170 °C, for a suitable time, for example 3 minutes.

[0214] VIII: Advanced Analytical Methods The following describes analytical methods for analyzing different properties such as compressive force, expansion ratio, and starch solubility.

[0215] Method for Measuring Thickness Cooking Expansion Ratio Cut the extruded product into thick pieces by cutting through in a direction perpendicular to the protein fiber direction (the direction in which the extruded product exits the extrusion die). The length of this thick piece is equal to the original width of the extruded product. The thickness of this thick piece is equal to the original thickness of the extruded product. The width of this thick piece is 20 mm. The width test direction is parallel to the fiber direction.

[0216] Place the thick piece in a beaker-shaped container. Then add water to the container to submerge the thick piece. Then cook the water and the thick piece in a pressure cooker at 110 °C for 10 minutes.

[0217] After cooking, remove the thick piece from the water and let it drain on a kitchen sieve. Measure and compare the thickness of the thick piece before and after cooking. The expansion ratio is calculated as: the thickness after cooking divided by the thickness before cooking. Measure the thickness of the thick piece at the center of its length direction. Unless otherwise clearly stated, such as "extrusion expansion ratio", the thickness cooking expansion ratio is expressed as "expansion" or "expansion ratio" throughout this application. Expansion ratio = 100% x Thickness (after cooking) / Thickness (before cooking).

[0218] Method for Observing Visible Air Cavities in an Extruded Product: Cut the extruded product into thick pieces (thick piece A) by cutting through in a direction perpendicular to the protein fiber direction (the direction in which the extruded product exits the extrusion die). The length of this thick piece is equal to the original width of the extruded product. The thickness of this thick piece is equal to the original thickness of the extruded product. The width of this thick piece is 20 mm. The width test direction is parallel to the fiber direction.

[0219] Cut the extruded product into thick pieces (thick piece B) by taking the middle part (at the middle of the width of the extruded product), so that this thick piece has a thickness equal to its original thickness, a length of 40 mm in the direction parallel to the fiber direction of the extruded product, and a width of 20 mm in the direction parallel to the width of the extruded product.

[0220] Place thick block A and thick block B into a beaker-shaped container. Then add water to the container to submerge the thick blocks. Then heat the water and the thick blocks at 60 °C for 24 hours.

[0221] After heating, take the thick blocks out of the water and let them drain on a kitchen sieve. Then observe the cut cross-sections (length x thickness) of thick block A and thick block B by visual inspection and taking photos.

[0222] Then air-dry the thick blocks at room temperature for 7 days. Analyze the dried thick blocks by X-ray microtomography (Micro-CT) scanning.

[0223] Method for measuring soluble starch concentration This method incorporates modifications to [Reference 10] and [Reference 11].

[0224] Mix a solution containing soluble starch (1 mL) with diluted Lugol's solution* (1 mL) and water (4 mL). Hand-shake the mixture for about 10 seconds and then let the mixture stand still for 10 minutes. Then measure the absorbance** of the mixture solution at a wavelength of 600 nm (the wavelength of the light beam used in the spectrophotometer measurement). *Prepare the diluted Lugol's solution by mixing 1 part of Lugol's solution (synonyms: iodine / potassium iodide solution, aqueous solution of potassium iodide and iodine, iodine concentration between 3% and 10%) or a stabilized Lugol's solution (a complex of iodine - polyvinylpyrrolidone (PVP) (a homopolymer derived from 1-vinyl-2-pyrrolidone, complexed with iodine at a concentration of 3% to 10%)) and 5 parts of water. An example of the final concentration after dilution: iodine concentration of 0.0100 mol / L and potassium iodide concentration of 0.0260 mol / L.

[0225] **The absorbance is measured by an ultraviolet / visible spectrophotometer (an example ultraviolet / visible spectrophotometer could be the UV-1600PC from Supplier VWR Collection).

[0226] Prepare a standard curve of absorbance and soluble starch concentration as follows: Disperse potato starch (0.05 g, 0.1 g, and 0.2 g) in 200 mL of cold water by hand-shaking for 1 minute. Then steam the dispersion twice in a pressure cooker (each time for 10 minutes at 110 °C, and hand-shake for 1 minute each time when the mixture is still above 60 °C after each steaming). In this way, the potato starch is completely dissolved in water. Centrifuge the potato starch dispersion at 644 g (g is the unit of RCF = relative centrifugal force) at room temperature. Then take the supernatant as the starch solution for further analysis. This can be done using the centrifuge used in this study, namely Heraeus TMMegafuge TM Centrifuge using an 8-place benchtop centrifuge equipped with a rotor that is a 50 mL conical tube (supplier's part number 75005703).

[0227] Based on the standard curve and the absorbance value at a wavelength of 600 nm, the concentration of soluble starch in the starch solution can be calculated.

[0228] Citation McGrance (1998) [Reference 10], "The reaction between starch and iodine has been known for over a century. Over fifty years ago, Rundle and Baldwin proposed that the iodine component of the complex exists in a one-dimensional array within the amylose helix, with six glucose residues per turn of the amylose helix. Two important aspects of the colorimetric method using the iodine reaction are its generality and simplicity. It can be used for starches from a variety of plant sources and requires no special equipment other than a simple spectrophotometer capable of measuring absorbance near 600 nm. Samples with high and low amylose content can be analyzed, and only the volume of the selected aliquot needs to be changed to obtain optimal results. The sensitivity of the iodine-starch reaction is quite high." Although the iodine colorimetric analysis method is not often used as an official analytical method, its use for starch quantification is reliable and is known to those skilled in the art.

[0229] Method for analyzing soluble starch and washable starch from an extruded product The method for extracting and defining soluble starch and washable starch employs a modification of [Reference 12]. Soluble starch is starch that can be extracted (extraction = elution) from the product with water at 50°C, passes through a sieve with a pore size of 1200 μm, and is soluble in water. Washable starch is starch and starch-containing material that can be extracted (extraction = elution) from the product with water at 50°C and passes through a sieve with a pore size of 1200 μm. Soluble starch is a part of washable starch; in other words, soluble starch is a synonym for "soluble washable starch". Washable starch includes soluble washable starch and insoluble washable starch. When insoluble washable starch is cooked at a temperature above its gelatinization temperature, preferably about 100°C, it can be dissolved in water. The soluble component is the component in the solution that is well dispersed in the liquid and does not precipitate during centrifugation at 644 g (g is the unit of RCF = relative centrifugal force).

[0230] Figure 13 Schematic of a method for analyzing soluble starch and washable starch from an extruded product 61: (Step 62) Cut avoiding the edges (5% of the width) to take a sample 63 approximately from the middle of the extruded product 62; (Step 64) Cut the sample 63 into thin slices 65. The thin slices 65 of the extruded product have dimensions of approximately 1 mm x 10 mm x 40 mm, where the length (40 mm) direction of the slice is parallel to the fiber orientation direction of the extruded product; (Step 66) Immerse the thin slices 65 in water at 50 °C for 24 hours and shake by hand for 2 minutes; (Step 67) Sieve through a 1.2 mm pore size; Reference numeral 68 refers to the insoluble washable components in the wash extract; (Step 69) Centrifuge at 644 g (RCF) for 30 minutes; Reference numeral 70 refers to the supernatant obtained by centrifugation, which contains soluble starch; (Step 71) Autoclave at 110 °C for 10 minutes and shake by hand; (Step 72) Centrifuge at 644 g (RCF) for 30 minutes; Reference numeral 73 refers to the supernatant obtained by centrifugation, which contains washable starch.

[0231] Measure 20 g of the sliced extrudate, soak it (step 66) in 200 mL of water, and keep it at 50 °C for 24 hours.

[0232] g is the unit of RCF = relative centrifugal force.

[0233] The starch solubility of the extruded product = (content of soluble starch / total starch content in the extruded product) x 100% The starch washability of the extruded product = (content of washable starch / total starch content in the extruded product) x 100%.

[0234] Method for measuring the total starch of the extruded product The total amount of starch in the extruded product can be analyzed by standard starch analysis methods such as the AACCI method 76 - 13.01 "Total Starch Determination Procedure" (Megazyme amyloglucosidase / α - amylase method). And it can also be measured by the hot water analysis method, which has the following steps: (1) Cut the extruded product into cubes of approximately 1 mm 3 ; (2) Cook 4 g of the cut extrudate in 200 mL of water in a pressure cooker at 110 °C for 10 minutes; (3) When the extrudate - water mixture is taken out of the pressure cooker oven above 70 °C, shake the extrudate - water mixture by hand. (4) Repeat step (3) for cooking and shaking again. With this treatment, it can be considered that all the starch is dissolved in water. (5) Centrifuge the extrudate - water mixture at 644 g (RCF) for 30 minutes, and (6) Measure the soluble starch concentration of the supernatant. The total amount of starch in the supernatant is equal to the total starch content of the extrudate, which can be calculated using the volume of water and the value of the soluble starch concentration.

[0235] Method for Measuring Cutting Force and Compression Force For cutting force measurement, we measured the resistance of the sample during the compression test with a blade. The measurement was carried out such that the TA.XTPlus texture analyzer (supplier Stable Micro Systems) was equipped with a 294.2 N (30 kg) load cell (detector sensor) and a sharp blade. The blade was of the "double bevel (ground) Scandi" type. The blade had an edge with a total wedge angle of approximately 16 degrees at the sharpest part (edge), which means that the main angle of the bevel of the blade was approximately 8 degrees. The blade had a flat part (ridge) 0.6 mm thick above the edge part. The height of the sample was between 7.0 and 12.0 mm. The width of the sample was 20 mm. The sample was stabilized and placed horizontally on the plate, and the orientation of the sample was adjusted so that the edge compressed (i.e., cut) in the transverse direction of the elongated fibers (the length direction of the fibers). The downward speed before the edge contacted the fibers was 4 mm / s (pre-test speed). The compression speed when the edge contacted the fibers was 20 mm / s (test speed), and the compression was carried out until a cutting depth of 90% of the sample height was reached. For samples with a height greater than 9.0 mm, the compression was carried out to a cutting depth of 8.0 mm. For this study, the peak positive force (peak positive force is a term used in the equipment software, which refers to the maximum force detected during the measurement) was taken as the cutting force.

[0236] For compression force measurement, we measured the resistance of the sample during the compression test with a cylindrical probe (model "P / 36R", 36 mm radius edge cylindrical probe - aluminum - AACC standard probe for bread firmness, supplier Stable Micro Systems). The measurement was carried out such that the TA.XTPlus texture analyzer was equipped with a 294.2 N (30 kg) load cell (detector sensor) and a cylindrical probe. The height of the sample was between 7.0 and 12.0 mm. The width and length of the sample were 40 mm. The sample was stabilized and placed horizontally on the plate, and the orientation of the sample was adjusted so that the cylinder compressed towards the center of the sample. The downward speed before the edge contacted the fibers was 2 mm / s (pre-test speed). The compression speed when the edge contacted the fibers was 0.5 mm / s (test speed), and the compression was carried out until a cutting depth of 40% of the sample height was reached. For this study, the peak positive force (peak positive force is a term used in the equipment software, which refers to the maximum force detected during the measurement) was taken as the compression force. There was a "trigger force" setting, which was set to 1000 g in this study. The trigger force was set to control the machine (texture analyzer). When the detected resistance was lower than the trigger force, the probe was not in the position of the top surface where the sample was contacted, and the probe moved downward at a pre-test speed of 2 mm / s. When the detected resistance was not less than the trigger force, the probe reached the sample, and the probe moved downward at a test speed of 0.5 mm / s.

[0237] Method for measuring hardness For hardness measurement, we measured the resistance of the sample during the compression test using a cylindrical probe (model "P / 36R", 36 mm radius edge cylindrical probe - aluminum - AACC standard probe for bread hardness, supplier Stable Micro Systems). The measurement was carried out such that the TA.XTPlus texture analyzer was equipped with a 294.2 N (30 kg) load cell (detector sensor) and the cylindrical probe. The height of the sample was between 7.0 and 12.0 mm. The width and length of the sample were 40 mm. The sample was stabilized and placed horizontally on the plate, and the orientation of the sample was adjusted so that the cylindrical compression was towards the center of the sample.

[0238] The test procedure used the standard TPA measurement protocol (citation from the measurement device manual: "Texture Profile Analysis (TPA) is an objective method of sensory analysis pioneered by Szczesniak in 1963 [Reference 6], who defined the texture parameters first used in this analytical method. Subsequently in 1978, Bourne [Reference 7] modified an Instron to perform TPA by compressing a standard-sized food sample twice. TPA is based on recognizing texture as a multi-parameter attribute. For research purposes, it may be desirable to determine the texture profile with respect to several parameters for small, homogeneous samples. The test consists of a reciprocating motion that mimics the action of the jaw to compress a bite-sized piece of food twice, and extracting a large number of texture parameters from the resulting force-time curve that are highly relevant to the sensory evaluation of those parameters [Reference 8]. To a large extent, the mechanical texture properties of foods that control the rheological program and the choice of equipment can be classified into primary parameters of hardness, cohesiveness, elasticity (springiness), and adhesiveness, and secondary (derived) parameters of fracturability (brittleness), chewiness, and gumminess [Reference 9].

[0239] The downward speed before the blade contacts the fiber is 5 mm / s (pre-test speed). When the blade contacts the fiber, the compression speed is 2 mm / s (test speed), and the compression is carried out until a cutting depth of 30% of the sample height is reached. For this study, the peak positive force (peak positive force is the term used in the equipment software, which refers to the maximum force detected during the measurement) was taken as the compression force. There is a "trigger force" setting, which was set to 5000 g in this study. The waiting time between the first compression and the second compression is 1 second, and the hardness is calculated by the software of the measurement device. The hardness is equal to the peak positive force during the first compression.

[0240] IX: Advanced mechanism research Mechanism study 1 shows the effects of processing methods (composition, impact heating) on the properties of the tested extrusions (materials extruded without a cooled die) (particle size distribution), which reveals how these processing methods affect the mechanism of the extruded products. This can also be used as an evaluation method for selecting processing parameters.

[0241] Further mechanism studies show relevant knowledge about the differences between the properties of grains and flours, and between grains processed with cold water and grains processed with warm water.

[0242] Mechanism study - 1 - Effects of composition and extrusion temperature distribution on particle weight distribution To study the effects of composition and extrusion temperature on the results, the inventors conducted a large number of further experiments. Table VIII lists the composition and tested extrusion parameters. Test extrusion means that during these tests, no die was installed on the extruder, and only the composition was processed through a screw running in a heating chamber. A summary of the results and findings can be seen in Table IX. Figure 4 Shows the particle weight distribution measured for the extruded materials affected by the composition and extrusion heating temperature distribution for Experiments 1 to 6.

[0243] Table VIII. Sample preparation for test extrusion Oat flakes were used as mechanically processed starch-containing grains in Experiments 2 and 3. In Experiments 4, 5, and 6, steel-cut oats were used. The steel-cut oats were not soaked before test extrusion.

[0244] Test extrusion did not form thick blocks with a long continuous fiber matrix. Instead, the resulting material was aggregates of different sizes (so the weight per particle was in the range of 0.1 g to 10 g). The aggregates (i.e., particles) were divided into different size (weight) groups (small, medium, large, etc.), then each size group was weighed, and its percentage relative to the total weight of the produced aggregates was calculated. Figure 4 The particle weight distribution curves are shown in.

[0245] Table IX: Results and findings of test extrusion Comparisons should mainly be made between samples with the same chemical composition (protein content, starch content, etc.), such as between Experiment 1, Experiment 2, and Experiment 3, or separately between Experiment 4, Experiment 5, and Experiment 6.

[0246] In addition, there are similarities between Experiment 1 and Experiment 4, which have parameters that can produce products with good compressibility and flexibility. They both produce medium-sized particles (0.5 g - 4 g) with a percentage between 26% - 30%; large particles (>4 g) with a percentage between 0% - 5%.

[0247] Mechanism study 2. Comparison of the particle size, seed coat, seed structure integrity, and starch extractability among oat groats, rolled oats, steel-cut oats, and whole oat seeds The measurement results in Table X show that due to the better integrity of the seed structure and seed coat, the starch extractability in water of rolled oats, steel-cut oats, and whole oat seeds (9–26 g / 100 g) is much lower than that of oat groats (40 g / 100 g). Due to the intact seed coat of whole oat seeds, their starch extractability is very low (9 g / 100 g).

[0248] When the water is hot, steel-cut oats can absorb much more and faster water (375%, 110 °C, 10 minutes) than when the water temperature is lower (136%, 50 °C, 12 hours). These explain why impact heating and soaking in hot water can change the behavior and effect of rolled oats and steel-cut oats in high-moisture extrusion. Hot water can allow the starch-containing grains to absorb water faster and more completely, and become gelatinized and more soluble.

[0249] Whole oat seeds do not have the functionality / substitutability like rolled oats and steel-cut oats in the embodiments disclosed above. At the time of writing, the inventors are still testing other treatments to enable whole oat seeds to have functionality. For example, boiling them thoroughly in excess water.

[0250] Table X: Oat-based starting materials, starch extractability in water To measure the extractable starch, 10 g of the starting material was steamed in 100 g of water in a pressure cooker for 10 minutes, and the steamed mixture was centrifuged at 644 g (RCF) for 30 minutes. The soluble starch concentration of the supernatant. The extractable starch was calculated as: Extractable starch = 100% x soluble starch in the supernatant / weight of the starting material.

[0251] To measure the water absorption at 50 °C, 20 g of the starting material was immersed in 200 g of water, then kept soaked at 50 °C for 24 hours, and then sieved to remove the water not absorbed by the material. The weights of the material before and after the 24-hour soak were recorded. Water absorption = 100% x (weight after soak - weight before soak) / weight before soak.

[0252] To measure the water absorption at 50 °C, 20 g of the starting material was added to 200 g of water, then steamed in this water at 110 °C in a pressure cooker for 10 minutes, and then sieved to remove the water not absorbed by the material. The weights of the material before and after steaming were recorded. Water absorption = 100% x (weight after steaming - weight before steaming) / weight before soak.

[0253] Steel cut oats with different sizes can be produced, with the size range being from 6 mm 3 to 15 mm 3 per particle. Those with 8 mm 3 per particle were used in this Mechanism Study 2.

[0254] Mechanism Study 3: The effect of soaking steel cut oats on its mechanical properties The inventors studied the effect of soaking steel cut oats. Figure 5 And the table shows the results of compression tests of dry (unsoaked) steel cut oats versus soaked steel cut oats (soaked in hot water).

[0255] It can be seen from Figure 5 that steel cut oats without soaking water are significantly more brittle and less compressible than steel cut oats soaked in hot water. When the compression rate reaches 27% (compressing 1.78 mm thick steel cut oats by 0.47 mm deep), the unsoaked steel cut oats have cracked and split. On the other hand, the steel cut oats soaked in hot water (80 °C, 2 hours) become softer, more viscous and pasty. The soaked steel cut oats did not crack or split during the entire compression (compressed between 0% - 90% during the test).

[0256] This reveals that starch-containing grains can be split into smaller pieces by the compressive force, which is sufficient during the extrusion process.

[0257] Treating starch-containing grains with hot water can soften the grains and help prevent the grains from being split into smaller pieces by compression or extrusion.

[0258] Table XI: The effect of soaking steel cut oats on its mechanical properties As an overview of comparing the properties of soluble starch content, washable starch content, starch solubility and starch washability when the protein content is the same, the inventors reviewed and classified the results and calculated the changes in these values. In Table XII, S1, S3, S4, S5 and S6 have the same composition and extrusion conditions as in Sample No. 1, Sample No. 2, Sample No. 6, Sample No. 11 and Sample No. 13. S2 has the same composition as Sample No. 2, but it has different extrusion conditions. In S2, the steel cut oats were not soaked in hot water before extrusion, and impact heating was achieved by using hot water (60 °C) liquid feed and an extruder temperature profile of 100 - 125 - 160 - 145 - 130 (°C) at zones 2 - 3 - 4 - 5 - 6.

[0259] Table XII shows that S2 has a starch solubility 52% higher and a starch washability 63% higher than S1. These differences are attributed to shock heating and compositional differences (such as the use of steel-cut oats). For S3, which uses steel-cut oats, soaking, and shock heating, the starch solubility and starch washability are even higher. When the pea protein content is reduced from 90% to 70%, the effects of composition (such as the use of steel-cut oats) and shock heating are even greater. S6 has a starch solubility 261% higher and a starch washability 58% higher than S4. Due to differences in shock heating, the starch solubility and starch washability of S5 are not as high as those of S6.

[0260] Table XII: Effects of Extrusion Conditions and Composition on Soluble Starch Content, Washable Starch Content, Starch Solubility, and Starch Washability Properties X: Conclusions The inventors have surprisingly found that starch added in the form of a starch powder or flour can indeed cause individual protein matrix portions to glue together to form an even larger sheet or a more complete structure during the extrusion process with or without a long cooling die.

[0261] The extruded products produced by adding the starch powder also have much higher isotropic properties and much lower anisotropic properties (anisotropic fiber structure, anisotropic texture).

[0262] The inventors have also found that small-sized starch can be emulsified into and / or between protein fibers to become a filler material in a protein-based emulsion gel-like system, capable of improving the uniformity and coverage (area, space, volume) of the protein material distribution. As a result, during the entire extrusion process, the proteins can form more isotropic interactions with each other. Starch gelatinization can also combine the materials of different parts to be interconnected.

[0263] The inventors have also found that when a long cooling die is used in extrusion, such materials with a higher amount of added starch powder can form a thicker, denser, and more isotropic thick mass with a specific fiber structure. When no cooling die is used in extrusion, such materials with a higher amount of added starch powder can form a larger extruded product connection mass (sheet) without a fiber structure.

[0264] The inventors have also found that, as described in the method item, when a starch-containing grain is added to a protein material and extruded, the problem of protein matrix hardening can be prevented or at least further delayed.

[0265] Without wishing to be bound by any theory and considering the very limited knowledge in this field, the inventors have found and there is a possible explanation that, when the starch-containing grains have a larger particle size than conventional starch-containing powders, the starch-containing grains break into smaller parts at a much slower rate. In addition, the broken grain parts are not easily emulsified by the protein matrix. The broken grain parts can still be gelatinized by sufficient heat, shear, and water. In addition, the naturally occurring grain cell wall structure and materials can limit the complete leaching, alignment, and retrogradation of starch molecules.

[0266] The naturally occurring grain cell wall structure and the gelatinization effect of the gelatinized starch can also prevent the grains from being completely pulverized into very fine particles (e.g., with a particle size below 100 μm). As a result, a large number of gelatinized starch clusters are formed and remain residual throughout the extrusion process and in the final product.

[0267] The inventors surprisingly found that when the extruded product is cut into thin slices but not necessarily completely disrupting the protein fibers, at least some of these clusters can be washed out of the extruded product with warm water (50 °C) without further gelatinizing the starch. These starch clusters have a much larger particle size than the starch in the traditional process, where the starch in the traditional production is individual and homogenized and emulsified in the protein matrix. These starch clusters are typically greater than 100 μm in at least one of their dimensions. As a result, these starch clusters can act like large particles, which can separate the protein fibers away from each other and thus prevent the formation of hydrogen bond-type protein-protein interactions and texture hardening.

[0268] The large starch clusters as large particles also often cause the formation of pores (cavities) or empty spaces beside them. This may be due to the flow behavior of the extruded material during extrusion and the protein fiber strength, allowing the protein fibers to flow away from each other after encountering the large particle barrier formed by the starch clusters. Then, after flowing away from each other continuously for a while, the bundles of protein material (protein fibers) approach and interact with each other again. During the period when the proteins flow away from each other, empty spaces are formed behind the large starch cluster particles. The protein fibers separated by the empty spaces cannot form hydrogen bonds. The inventors believe that this may contribute to a better texture being maintained for a longer time, even in cooled or frozen meat alternative products.

[0269] In addition, the inventors have found that the earlier the starch in the grain is gelatinized before being emulsified by the protein matrix, the higher the concentration of gelatinized starch clusters, and the more effectively the formation of a continuous protein matrix can be prevented. Without wishing to be bound by any theory, the inventors have an explanation that the gelatinized starch clusters that are not emulsified by the protein matrix are immiscible with the protein phase, and thus can cause the phase to separate from the protein phase, thereby forming a relatively large continuous phase and disrupting the formation of protein-protein interactions, so they can prevent to a certain extent the formation of a continuous protein fiber matrix. This explanation is very consistent with the test results in the mechanism research experiments in the selected embodiments described below. The differences observed among the numbers of samples examined by the inventors also seem to support this explanation.

[0270] After the formation of the gelatinized starch clusters, the melting, crosslinking, and gelation of the protein material should be initiated within a certain short time window. If this occurs too late, there can be two types of unacceptable results, namely (1) the gelatinized starch clusters are ultimately homogenized, fragmented, and emulsified by the protein matrix, which is especially likely when the amount of starch-containing grains added is small, or when the starch-containing grains are relatively easy to fragment and the composition contains a high content of starch powder; (2) the gelatinized starch clusters completely prevent the formation of long continuous protein fiber structures and the coagulation, aggregation, and gelation of proteins by separating and covering the protein material into separate clusters, which is especially likely when the amount of starch-containing grains added is relatively large and the composition contains a low content of starch powder.

[0271] In addition, the inventors have found that when the starch-containing grains added to the extruder are not soaked in hot water or not mixed with hot water at a very early stage (e.g., between 0 seconds and 15 seconds after being fed into the extruder, preferably between 1 second and 15 seconds) when added to the extruder, the starch-containing grains are more likely to be ground into powder in the extruder. Thus, the starch-containing grains behave similarly to their flours, which have the same chemical composition but smaller particle sizes and broken cell wall structures.

[0272] Conversely, starch-containing grains immersed in hot water before extrusion and starch-containing grains mixed with hot water at a very early stage during extrusion (e.g., between 0 seconds and 15 seconds after being fed into the extruder, preferably between 1 second and 15 seconds) will be less brittle, more extensible, and thus less likely to be emulsified by the protein matrix, and will be more likely to remain as large particles throughout the extrusion. Therefore, this is part of the reason for the importance and necessity of using extrusion conditions with impact heating settings when using starch-containing grains in the composition for extrusion to produce an acceptable quality extruded product.

[0273] The inventors have also surprisingly found that when produced by the methods described in the method items, meat alternative products manufactured by high moisture protein texturizing extrusion can have a significantly higher level of extrusion expansion rate shortly after the extruded product exits the long cooling die of the extruder.

[0274] At one second after the extruded product exits the long cooling die of the extruder, the high extrusion expansion rate during extrusion can be clearly seen. The extruded product obviously has air bubbles inside the expanded structure, and its thickness is much larger (e.g., 200%-600% higher) than its original thickness before leaving the long cooling die of the extruder (the original thickness is roughly the same as the opening height of the long cooling die of the extruder). After the extruded product cools, the expanded structure may mostly collapse. However, there are still relatively many cavity (in other words, air pocket) structure units remaining in the cooled extruded product. This difference may be attributed to the advantage of forming gelatinized starch clusters that are not emulsified by the protein matrix, which is generated by the methods described in the method items.

[0275] Gelatinized starch can result in a larger expansion rate in high moisture extrusion. The increase in the expansion rate can be attributed to the reduction in structural firmness and the reduction in the viscosity of the extruded material.

[0276] On the contrary, such extrusion expansion phenomenon is basically absent or, in other words, cannot be detected in such test processing methods that do not use starch-containing grains or do not have impact heating settings in the extrusion conditions. It is found that the extruded products produced by these processing methods that fail to produce products with a texture close to that of cooked chicken legs tend to have a denser and tighter structure (the thickness at one second after exiting the long cooling die of the extruder is 0% to 199% higher than before leaving the long cooling die of the extruder), and significantly fewer cavity structure units (in other words, air pockets) are retained after cooking. During high moisture extrusion, compared with starch-containing grains, starch-containing flours can result in a higher amount of leached starch, more water absorption, and a higher increase in viscosity. It is found that these are consistent with the observations during the extrusion test and are also consistent with the experimental study on the mechanism of cooking starch-containing materials in water in a pressure cooker.

[0277] The inventors have surprisingly found that for the extruded products produced by the methods described in the method items, when the extruded products are cut into thin slices but do not necessarily completely destroy the protein fibers, more starch molecules can be dissolved out of the extruded products by warm water (50°C). The temperature of 50°C is lower than the gelatinization temperature of starch. Generally, natural (non-gelatinized) starch is insoluble in water at 50°C. Pre-gelatinized starch and some modified starches can be dissolved in water at 50°C before they are used for meat alternative production by high moisture protein texturizing extrusion, but they lose their solubility after the extrusion process because they are quickly emulsified by the protein matrix after being extruded together with the protein material.

[0278] The starch dissolved in the extruded products described herein and below is soluble washable starch, which is part of the washable starch. Compared to insoluble washable starch, soluble starch (soluble washable starch) gelatinizes more completely, leaches out (is released from its confinement) more from the starch granule shell and the cell wall structure of the endosperm cells, has a higher affinity for water, and their molecules have a more swollen structure (such as volume and surface area). Soluble starch has an even smaller affinity for the protein matrix and is even less tightly embedded in or trapped by the long continuous protein fiber structure. Soluble starch is even less miscible with the protein phase, so it separates more completely from the protein phase by phase separation. Soluble starch is the main component coating the inner walls of the cavities (voids) of the acceptable extruded products. Soluble starch compounds are the main components and the main sites where extrusion expansion and cavity formation occur. After staining with a diluted iodine solution, the coating material on the inner walls of the cavities of the acceptable quality extruded products can be seen by visual and microscopic observation. After staining, the coating material turns dark blue or black, indicating a high concentration of starch. The cavities coated with gelatinized starch clusters also act as a new type of disruptive compound that prevents further formation of protein-protein interactions (such as hydrogen bonds) between the protein fibers after extrusion. The cavities coated with gelatinized starch clusters are different from and perform better than other known disruptive particles, such as starch, flour, insoluble salts, dietary fiber, apparently because the starch clusters keep the protein fibers farther apart within a volume larger than the size of the individual particles.

[0279] There is no background art teaching the role and influence of soluble starch, washable starch, insoluble washable starch, starch solubility, and starch washability in producing meat alternative products with a long continuous protein fiber structure by high-moisture protein texturizing extrusion or low-moisture protein texturizing extrusion. There may be some research on starch solubility in starch extrusion methods, which mainly process the starch components of starchy foods and have a configuration very different from protein texturizing extrusion. However, starch solubility is highly correlated with breadcrumb staling and texture quality. For example, Boyacioglu and D’Appolonia [Reference 5] reported that the breadcrumbs aged (stored, ripened) for more than 4 days may have a continuous, progressive, and significant decrease in starch solubility, while the firmness value continuously and significantly increases; it is recommended to use the soluble starch content to measure the rate and degree of staling because the decrease in soluble starch content indicates breadcrumb staling and increased firmness; the higher the amount of soluble starch in the aged breadcrumb sample, the lower the increase rate of the firmness value. In breadcrumbs, a decrease in starch solubility indicates an increase in the retrogradation rate of starch molecules. Starch retrogradation is a well-known factor that usually causes the leathery texture and hard texture of starchy foods such as bread. It occurs fastest at temperatures slightly above the freezing point (e.g., between 0 °C and 6 °C). Starch retrogradation is caused in part by the recrystallization of starch amylose and amylopectin molecules and is the result of an increase in starch-starch hydrogen bonding and a decrease in starch-water affinity. The associative thinking between the knowledge of starch solubility behavior in meat products produced by high-moisture protein texturizing extrusion and the knowledge of breadcrumbs is possible but not obvious. The meat alternative products produced by high-moisture protein texturizing extrusion have a completely different ingredient formulation, structure, and microstructure from breadcrumbs. Although the processes and structure formation mechanisms of protein texturizing extrusion and bread baking are also completely different.

[0280] The inventors surprisingly found that meat alternative products manufactured by high-moisture protein texturizing extrusion and having low starch solubility and low starch washability have most of their starch homogenized and emulsified uniformly by the protein matrix. Observed under a microscope, it was found that the emulsified starch in the product is linearly arranged such that the starch particles are parallel to each other. The protein fibers tightly cover and capture the starch compounds. The starch compounds are completely leached out. The original starch granule structure has basically disappeared. Therefore, the starch may undergo severe retrogradation. These findings are consistent with the results that those samples have low starch solubility, more severe hardening during 5 hours of storage, poorer compressibility after overnight storage, and poorer ability to expand by boiling in water in a pressure cooker. In contrast, it was found that meat alternative products with significantly high starch solubility and starch washability have better texture properties (good compressibility, good expansion properties, and a texture close to that of chicken drumsticks).

[0281] Starch solubility and starch washability are even more important than soluble starch content and washable starch content. Starch solubility and starch washability are calculated as the ratios of soluble starch content and washable starch content relative to the total starch in the extruded product. Soluble starch and washable starch make positive contributions to the quality (e.g., texture) of the extruded product. On the contrary, the higher the percentages and amounts of insoluble starch and un-washable starch, the worse the quality (e.g., texture) of the extruded product, because insoluble starch and un-washable starch are emulsified, trapped, and embedded in the protein matrix relatively more completely and have more retrogradation.

[0282] Regarding this background art and the inventors' new findings, there are reasons to believe in the importance of monitoring and controlling the levels of soluble starch content, washable starch content, starch solubility, and starch washability in meat alternative products manufactured by high-moisture protein texturizing extrusion.

[0283] Methods for controlling and improving starch solubility and starch washability in meat alternative products produced by high-moisture protein texturizing extrusion cannot be found in the background art and are disclosed in the following description.

[0284] The inventors have found that when a meat alternative product manufactured in an extruder configured to perform high-moisture protein texturizing extrusion contains a continuous protein fiber matrix structure, the continuous protein fiber structure is substantially linearly oriented and has disruptions that form cavities, where the walls of the cavities are at least partially coated with gelatinized starch clusters, the texture tends to remain acceptable for a long time.

[0285] It is known that a decrease in starch solubility (e.g., in water at 50 °C) and an increase in starch retrogradation are important factors causing the firming of the texture of foods (e.g., breadcrumbs containing a starch gel structure). See references (a) SOHOCH, T. J.; FRENCH, D. 1947. Studies on bread staling. 1. The role of starch. Cereal Chemistry, 24:231 - 249; (b) T. Inagaki and P. A. 1992. Firming of Bread Crumb with Cross-Linked Waxy Barley Starch Substituted for Wheat Starch. Cereal Chem 69:321 - 325; (c) K. Ghiasi, R. C. Hoseney, and D. R. Lineback. 1979. Characterization of Soluble Starch from Bread Crumb. Cereal Chem 56:485–490.

[0286] Alternatively or additionally, the gelatinized starch clusters include starch that is not emulsified by the protein fiber matrix structure (non-emulsified starch). The resulting advantages are: (1) an increase in the percentage of non-emulsified starch results in a decrease in the percentage of emulsified starch. Non-emulsified starch does not act as a filler that fills the gaps between protein fibers and enhances the overall extrudate structure, but emulsified starch does; (2) non-emulsified starch is less ordered (more disordered or less molecular) than emulsified starch, and thus there is less and / or delayed starch retrogradation, and improved softness at temperatures above freezing (e.g., between 0 °C and 6 °C) over the entire long storage time; (3) non-emulsified starch interferes with the arrangement of the protein fiber matrix structure, and thus improves its softness at temperatures above freezing (e.g., between 0 °C and 6 °C) over the entire long storage time by reducing and / or delaying the formation of intermolecular (e.g., protein-protein, starch-starch) hydrogen bonds in the extrudate.

[0287] Alternatively or additionally, a high-moisture protein texturization extrusion method can be used to manufacture meat alternative products, wherein the starch-containing grains are gelatinized, and: (a) before the gelatinized starch-containing grains and the protein of the protein matrix form an emulsion; and (b) before the gelatinized starch forms a complete barrier that prevents the formation of a continuous protein fiber crosslinked matrix, the protein forming the protein matrix is melted. The resulting advantage is that in this way, the extrusion material is controlled in a good balance between: (a) fully forming protein-protein crosslinks to form continuous protein fibers; and (b) preventing crosslink formation by gelatinized starch. As a result, the extrudate can have chewiness within a specific threshold range (cutting force higher than 300 g) and at the same time have compressibility within a specific threshold range (compression force lower than 17,500 g). If protein melting is not achieved before the gelatinized starch-containing grains and the protein material form an emulsion, emulsification can still be achieved by continuous shearing, tearing, and homogenization of the protein-starch mixture, and then the starch becomes emulsified and cannot prevent an increase in unwanted interaction forces (e.g., hydrogen bonds) and hardening of the extrudate (e.g., the compression force becomes higher than 17,500 g). On the other hand, if protein melting is not achieved before the gelatinized starch forms a complete barrier that prevents the formation of a continuous protein fiber crosslinked matrix, there will be a lack of protein-protein crosslinks. As a result, the chewiness will be too low and not within the threshold range (cutting force higher than 300 g).

[0288] The extrusion step can be carried out using an extrusion die with a length greater than 300 mm, preferably greater than 1000 mm. The advantage of this is that such dies are typical settings for implementing high-moisture protein texturization extrusion. This die allows the extruder to process the extrusion cooking of materials with a moisture content higher than 40% to form a textured (crosslinked) structure before the material exits the extruder. This die also allows the molten protein material to align into a long continuous fiber structure.

[0289] Preferably, the heating step d) is preferably carried out between 140 °C and 200 °C. The advantage resulting from this is that this temperature allows the protein to melt, denature, form a gel, and form the protein-protein crosslinks required to form a long continuous fiber structure.

[0290] Preferably, the mechanically processed starch-containing grains comprise one or more of the following or consist of one or more of: oats, barley, rye, wheat, rice, corn, lentils, chickpeas, mung beans, fava beans, peas, quinoa, pigeon peas, sorghum, buckwheat. The advantage resulting from this is that these grains are commercially available, contain a large amount of starch, are known to be palatable and nutritious, and are widely used in different other food applications.

[0291] Alternatively or additionally, the heating step d) is preferably carried out such that protein melting occurs between 1 s and 40 s after step b), preferably between 10 s and 30 s. The advantage resulting from this is that in this way, (a) before the protein in the gelatinized starch-containing grains and the protein matrix form an emulsion; and (b) before the gelatinized starch forms a complete barrier that prevents the formation of a continuous protein fiber crosslinked matrix, protein melting of the protein matrix occurs.

[0292] In the test, the time required for the extruder to break the grains (such as rolled oats, steel-cut oats, rice) into powder was observed.

[0293] Alternatively or additionally, the heating step c) is carried out such that starch gelatinization occurs between 0 s and 18 s, preferably between 1 s and 15 s. The advantage resulting from this is that in this way, it is possible to preferably carry out the heating step c) before the starch-containing grains are ground by the extruder screw into particles with a volume less than 5000 μm 3 and preferably before the starch-containing grains are ground by the extruder screw into particles with a volume less than 0.001 mm 3 The gelatinized starch clusters with a volume per particle greater than 5000 μm 3 are unemulsified starch, are larger than those emulsified starches, and can provide much greater destructive force to prevent the formation of overly excessive protein-protein interactions, and thus can prevent the hardening of the extrudate during storage.

[0294] Preferably, after the heating step d), at a temperature not higher than that of the heating step c), preferably between 90 °C and the temperature in the heating step d), the mixture is continuously extruded for more than 5 s, preferably more than 10 s. The advantages resulting therefrom are as follows: Such a heating level can cause a good balance between: (a) sufficiently forming a protein-protein crosslinked structure (force) to provide acceptable chewiness (cutting force higher than 300 g); and (b) having acceptable compressibility (compression force lower than 17,500 g). A higher temperature can lead to the formation of too much crosslinking and thus poor compressibility. A temperature below 90 °C can result in a structure that is too weak due to the lack of a co-aligned long fiber structure and poor chewiness.

[0295] XI - Summary To improve the texture of meat alternative products, improvements in meat alternative products and high-moisture protein texturizing extrusion have been invented. The inventors have found that by appropriately selecting extrusion parameters and starting materials containing mechanically processed starch grains, the formation of an emulsion between the starch and the protein melt forming the protein matrix can be prevented or reduced to such an extent that a large amount of unbound starch is present in the protein matrix. The presence of unbound starch in the protein matrix has been observed to improve the texture and maintain an acceptable texture for a long time. This patent application contains a large number of independent claims for meat alternative products and methods.

[0296] It will be apparent to those skilled in the art that, with technological progress, the basic idea of the present invention can be implemented in many ways. Therefore, the present invention and its embodiments are not limited to the examples and samples described above, but they can vary within the content of the patent claims and their legal equivalents.

[0297] In the foregoing description of the present invention, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising" are used in an inclusive sense by virtue of the language of expression or necessary implication, that is, specifying the presence of the stated features in various embodiments of the present invention, but not excluding the presence or addition of further features.

[0298] List of reference publications: [Reference 1] Tolstoguzov, V. B. (1993), Thermoplastic extrusion — the mechanism of the formation of extrudate structure and properties. J Am Oil Chem Soc, 70: 417 - 424. doi:10.1007 / BF02552717 [Reference 2] Akdogan, H. (1999), High moisture food extrusion. International Journal of Food Science & Technology, 34: 195 - 207. doi:10.1046 / j.1365 - 2621.1999.00256.x [Reference 3] Lin, S., Huff, H. and Hsieh, F. (2000), Texture and Chemical Characteristics of Soy Protein Meat Analog Extruded at High Moisture. Journal of Food Science, 65: 264 - 269. doi:10.1111 / j.1365 - 2621.2000.tb15991.x [Reference 4] Xiang Dong Sun, Susan D. Arntfield. (2010) Gelation properties of salt - extracted pea protein induced by heat treatment. Food Research International. Volume 43, Issue 2, 2010, Pages 509 - 515. [Reference 5] M. H. Boyacioglu and B. L. D’Appolonia. (1994) Characterization and utilization of durum wheat for breadmaking III. Staling properties of bread baked from bread wheat flours and durum wheat flours. Cereal Chemistry. 71: 34 - 41 [Reference 6] SZCZESNIAK, A.S. (1963). Classification of textural characteristics. J. Food Sci, 28, 385 - 389. [Reference 7] BOURNE, M.C. (1978). Texture Profile Analysis. Food Technol., 32(7), 62 - 66, 72. [Reference 8] BOURNE, M.C. (1988). Basic Principles of Food Texture Measurement. Lecture text of Dough Rheology and Baked Products Texture Workshop - Chicago. [Reference 9] SZCZESNIAK, A.S. (1966). Texture Measurements. Food Technol., 20, 50, 55 - 58.) [Reference 10] McGrance, S.J., Cornell, H.J. and Rix, C.J. (1998), A Simple and Rapid Colorimetric Method for the Determination of Amylose in Starch Products. Starch / 50:158 - 163. doi:10.1002 / (SICI)1521 - 379X(199804)50:4<158::AID - STAR158>3.0.CO;2 - 7. [Reference 11] Adedeji, O.E., Oyinloye, O.D., & Ocheme, O.B. (2014). Effects of germination time on the functional properties of maize flour and the degree of gelatinization of its cookies. African Journal of Food Science, 8(1), 42 - 47. [Reference 12] Azarfar, A., Williams, B. A., Boer, H. and Tamminga, S. (2007) In vitro gas production profile and the formation of end products from non-washable, insoluble washable and soluble washable fractions in some concentrate ingredients. Journal of the Science of Food and Agriculture. 87: 1345 - 1355

Claims

1. A meat alternative product, comprising: An extrudate, which is manufactured by high moisture protein texturization extrusion, i.e., such that the moisture content during extrusion is between 40% - 80%, and the extrudate has a substantially linearly oriented continuous protein fiber matrix structure, The matrix contains disruptions in the matrix structure, Some of the disruptions in the matrix structure are in the form of cavities, and the cavities have walls at least partially coated with gelatinized starch clusters, which are formed from starch, Such that when measuring the extrudate, at least 5.1%, preferably at least 5.2% of the starch is soluble starch, and the soluble starch is located at the disruptions in the matrix structure and is not emulsified by the matrix structure.

2. The meat alternative product according to claim 1, wherein: The soluble starch is in the form of clusters and phase separates from the protein phase and is not emulsified by the protein.

3. A meat alternative product, wherein: The meat alternative product comprises an extrudate, which is manufactured by high moisture protein texturization extrusion and has a substantially linearly oriented continuous protein fiber matrix structure, and the extrudate comprises gelatinized starch clusters located at the disruptions in the matrix structure and not emulsified by the matrix structure, such that when measuring the extrudate, i) when the protein content of the extrudate is greater than 55% by weight but less than 70% by weight, at least 10.5% of the starch in the extrudate is washable starch, ii) when the protein content of the extrudate is at least 70% by weight but less than 90% by weight, at least 15% of the starch in the extrudate is washable starch, iii) when the protein content of the extrudate is at least 90% by weight but equal to or less than 99% by weight, at least 16% of the starch in the extrudate is washable starch, wherein the indicated % by weight is based on a dry basis.

4. The meat alternative product according to claim 3, wherein: The washable starch is washable in water at a temperature of 50 °C.

5. The meat substitute product according to claim 3 or 4, wherein: The washable starch is located at the disruptions in the matrix structure and is not emulsified by the matrix structure.

6. The meat alternative product according to claim 5, wherein: Some of the disruptions in the matrix structure are in the form of cavities, and the cavities have walls at least partially coated with gelatinized starch clusters, which are formed from washable starch.

7. The meat substitute product according to any one of the preceding claims 1 and / or 6, wherein: The starch clusters contain washable starch that is washable in water at a temperature of 50 °C.

8. The meat alternative product according to any one of the preceding claims, comprising: starch clusters with a size (e.g., length) greater than about 100 μm.

9. A meat alternative product, wherein: The meat alternative product comprises an extrudate having a substantially linearly oriented continuous protein fiber matrix structure, and the extrudate comprises starch, and wherein: the extrudate is manufactured using a high moisture protein texturization extrusion method, in which starch-containing grains are gelatinized and the protein forming the protein matrix is melted, such that the starch-containing grains are gelatinized before they are substantially pulverized by the extruder screw.

10. A meat substitute product, wherein: The meat alternative product comprises an extrudate having a substantially linearly oriented continuous protein fiber matrix structure, and the extrudate comprises starch, and wherein: the extrudate is manufactured using a high moisture protein texturization extrusion method, in which starch-containing grains are gelatinized and the protein forming the protein matrix is melted, such that: (a) before the protein in the gelatinized starch-containing grain and the protein matrix forms an emulsion, and (b) before the gelatinized starch forms a complete barrier that prevents the formation of a continuous crosslinked matrix of protein fibers, the protein is melted.

11. A meat alternative product, comprising: an extrudate having a substantially linearly oriented continuous protein fiber matrix structure, the extrudate being manufactured by high moisture protein texturizing extrusion and comprising starch located at disruptions in the matrix structure and not emulsified by the matrix structure, wherein: some of the disruptions in the matrix structure are in the form of cavities having walls at least partially coated with clusters of gelatinized starch formed from starch.

12. The meat substitute product according to claim 11, wherein: The clusters of gelatinized starch formed from starch are formed from soluble starch or washable starch.

13. The meat substitute product according to any one of the preceding claims, wherein: The extrudate is an extrudate manufactured using a high moisture protein texturizing extrusion method with a twin screw extruder having a long cooling die.

14. The meat substitute product according to claim 13, wherein: The length of the long cooling die is at least 300 mm, preferably at least 1000 mm, and most preferably between 1000 mm and 5000 mm.

15. The meat alternative product according to any one of claims 1-14, wherein: The meat alternative product is in the form of a thick block, rib, cube, slice, cutlet or doner kebab-like slice, or in the form of a doner kebab-like laminated layer in yogurt or vegan yogurt and spices.

16. The meat alternative product according to any one of claims 1 - 15, comprising a mechanically processed starch-containing grain selected from: oats, barley, rye, wheat, rice, maize, lentils, chickpeas, mung beans, broad beans, peas, quinoa, pigeon peas, sorghum, buckwheat, excluding: dehulled but unpearled oat grains, dehulled but unpearled rye grains, dehulled but unpearled barley grains, dehulled but unpearled maize grains.

17. The meat substitute product according to any one of claims 1-16, wherein: The mechanically processed starch-containing grain comprises one or more of or consists of one or more of: cereal flakes (such as compressed, flattened or fragmented), steel cut grains, dehulled pearled grains, crushed grains, dehulled but unpearled grains, excluding: dehulled but unpearled oat grains, dehulled but unpearled rye grains, dehulled but unpearled barley grains, dehulled but unpearled maize grains.

18. The meat alternative product according to claim 16 or 17, wherein: The mechanically processed starchy grains have a particulate volume of at least 0.125 mm 3 , preferably at least 1 mm 3 , most preferably at least 6 mm 3 in volume of the particles.

19. The meat alternative product according to claim 18, wherein: The mechanically processed starch-containing grains are steel-cut grains and have a particulate volume of at least 0.125 mm 3 , preferably at least 1 mm 3 , most preferably at least 6 mm 3 of particulate volume.

20. The meat alternative product according to claim 18, wherein: The machined starchy grain has a particulate volume of at least 1 mm 3 in size.

21. The meat substitute product according to claim 18, wherein: The machined starch-containing grain has a particle volume of at least 6 mm 3 in size.

22. The meat alternative product according to claim 16 or 17, wherein: The starch-containing grains are ground by the extruder screw to a volume of less than 5000 μm per particle 3 .

23. The meat alternative product according to any one of claims 1-22, wherein: When measured at least 24 hours after extrusion, the linear compressibility is between 300 g and 1500 g, and the cylindrical compressibility is between 7000 g and 17500 g.

24. The meat alternative product according to any one of claims 1 - 23, further comprising oil, spices and any other ingredients.

25. A twin-screw extruder for high-moisture protein texturizing extrusion, comprising: a screw barrel (138) for accommodating an extruder screw (126), the extruder screw (126) defining the direction of movement of the material in the extruder (13) relative to the barrel (138), the barrel (138) further comprising a first inlet hole (139) for receiving solid components into the extruder (13) and a second inlet hole (140) for receiving liquid into the extruder (13), the second inlet hole (140) being located downstream of the first inlet hole (139) along the flow direction, the extruder (13) i) being connected to a warm water supply having a temperature of at least 50 °C, or ii) comprising a heating element (14) configured to heat water from a water supply to a temperature of at least 50 °C before passing the water from the water supply into the second inlet hole (140); The extruder further comprises a long cooling die (125), the long cooling die being longer than 300 mm, preferably having a length between 300 mm and 5000 mm, and most preferably between 1000 mm and 3000 mm.

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