Soybean protein particles, high-satiety double-layer protein bar containing same, and preparation method and application of high-satiety double-layer protein bar

Abstract

The invention discloses soybean protein particles, a high-satiety double-layer protein bar containing the soybean protein particles as well as a preparation method and application of the high-satiety double-layer protein bar. Specifically, the invention provides a preparation method of soybean protein particles, which comprises the following steps: S1, carrying out ultrasonic treatment on a soybean protein isolate dispersion liquid, and drying to obtain soybean protein isolate particles; s2, cassava starch and amylase are mixed, and porous cassava starch particles are obtained through an enzymolysis reaction and drying; and S3, performing wet mixing on raw materials including the soybean protein isolate particles and the porous cassava starch particles by adopting a double-screw rod extrusion process to prepare the soybean protein particles. The soybean protein particles prepared by the method disclosed by the invention have very good crisp mouth feel, are resistant to storage and not easy to damp, and also have a relatively good anti-digestion effect, and after the soybean protein particles are added into the protein bar, the loss of the crisp mouth feel of the protein bar in the long-term storage process can be reduced, and the hunger sensation can be delayed.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and particularly to a soy protein particle, a high satiety double-layer protein bar containing the same, and a preparation method and application thereof. Background Art

[0002] A protein bar is a type of food containing a high proportion of protein, which can effectively supplement the energy required by the body in a short time, so it is widely used in the field of functional foods such as sports and fitness. With the improvement of people's living quality, more requirements are put forward for the flavor, texture and taste of protein bar foods.

[0003] Soy protein particles are one of the main components providing a crispy texture in protein bars. They are products obtained by extrusion and puffing of soy protein isolate, tapioca starch or rice flour, etc. Different from general drawn protein, the protein content of soy protein particles is usually about 80%. After being puffed with tapioca starch, etc., they can provide a good crispy texture. In related technologies, soy protein particles are prone to absorb moisture and become soft during long-term storage, resulting in the loss of the crispy texture. During the preparation of protein bars, a coating is usually added to reduce the loss of the crispy texture. However, in actual applications, compared with the way directly exposed to the outer layer, although adding a coating can extend the retention time of the crispy texture to a certain extent, it is still difficult to meet the requirements of long-term storage.

[0004] Based on this, there is an urgent need to develop a soy protein particle that can not only improve the crispy texture but also effectively extend the retention time of the crispy texture, so as to reduce the loss of the crispy texture of protein bars during long-term storage. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a preparation method of soy protein particles. The soy protein particles prepared by this method have a good crispy texture and are not easily affected by moisture, and adding them to protein bars helps to reduce the loss of the crispy texture of protein bars during long-term storage.

[0006] The present invention also provides a soy protein particle.

[0007] The present invention also provides an application of the above preparation method of soy protein particles or soy protein particles in the preparation of related products.

[0008] The present invention also provides a high satiety double-layer protein bar containing the above soy protein particles.

[0009] The present invention also provides a preparation method of the above high satiety double-layer protein bar.

[0010] In a first aspect of the present invention, a method for preparing soy protein particles is provided, comprising: S1. subjecting a soy protein isolate dispersion to ultrasonic treatment, and drying to obtain soy protein isolate particles; S2. mixing tapioca starch and amylase, carrying out an enzymatic reaction, and drying to obtain porous tapioca starch particles; S3. using a twin-screw extrusion process to wet-mix raw materials including the soy protein isolate particles and the porous tapioca starch particles to prepare soy protein particles.

[0011] The preparation method according to an embodiment of the present invention has at least the following beneficial effects: The soy protein particles prepared by the preparation method of the present invention have a crispy texture and are not easily affected by moisture. First, the present invention uses ultrasonic treatment on soy protein isolate to disperse protein aggregates through the physical force generated by cavitation, and by changing the three-dimensional structure of protein molecules, more hydrophilic groups and regions are exposed, improving its hydrophilic properties. Second, the present invention mixes soy protein isolate particles with porous tapioca starch having a high specific surface area, and uses the high dispersibility and hydrophilicity of soy protein isolate particles to uniformly bind them to the porous tapioca starch. During the puffing process, at a relatively high temperature, the structure of soy protein isolate is damaged, causing its hydrophobic groups to be exposed, thereby improving the moisture absorption resistance of soy protein particles while retaining the crispy texture.

[0012] In some embodiments of the present invention, the frequency of the ultrasonic treatment is 25 - 35 kHz. For example, it can be 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 or 35 kHz.

[0013] In some embodiments of the present invention, the power of the ultrasonic treatment is 120 - 200 W. For example, it can be 120, 125, 130, 140, 150, 160, 180 or 200 W.

[0014] In some embodiments of the present invention, the time of the ultrasonic treatment is 10 - 25 min. For example, it can be 10, 12, 13, 14, 15, 16, 18, 20, 22, 24 or 25 min.

[0015] As the ultrasonic treatment time increases, the surface hydrophilicity of the protein increases with the increase of the ultrasonic treatment intensity, which helps to reduce the aggregation of soy protein isolate, improve the dispersibility and stability, and make the protein molecules form a more uniform network structure. However, as the ultrasonic power and time continue to increase, it is also easy to cause excessive damage to the structure of soy protein isolate, resulting in the exposure of its hydrophobic structure and affecting the dispersibility.

[0016] In some embodiments of the present invention, the concentration of the soy protein isolate dispersion is 1-15% (w / v). For example, it can be 1%, 2%, 3%, 5%, 8%, 10%, 12%, 14% or 15% (w / v).

[0017] In some embodiments of the present invention, the initial pH value of the soy protein isolate dispersion is 1.5-3.5 or 10.0-12.0. After the ultrasonic treatment, an operation of adjusting the pH value to 6.5-7.5 is further included. For example, the initial pH value of the soy protein isolate dispersion can be 1.5, 1.8, 2.0, 2.5, 3.0 or 3.5, or can also be 10.0, 10.5, 11.0, 11.5 or 12.0.

[0018] By adjusting the pH value of the reaction system, it helps to improve the solubility of the protein. This is because soy protein isolate can unfold at pH 1.5-3.5 or 10.0-12.0 and then refold around pH 7.0. This unfolding and refolding process can promote the formation of the fused globular structure of soy protein, form a more stable structure, and at the same time help to increase the protein solubility.

[0019] In some embodiments of the present invention, the pH adjustment adopts conventional acid-base adjustment methods, such as adding hydrochloric acid or sodium hydroxide.

[0020] In some embodiments of the present invention, the drying method includes freeze-drying or spray-drying. Freeze-drying is preferred.

[0021] During the freeze-drying process, water sublimes directly in the form of ice crystals without involving the evaporation of liquid water, which helps to maintain the structure and morphology of protein particles, and can effectively avoid the over-destruction of the structure of soy protein isolate particles, thereby preventing the excessive exposure of hydrophobic groups and affecting the dispersion performance.

[0022] In some embodiments of the present invention, in step S2, the amylase includes α-amylase and glucoamylase.

[0023] Both α-amylase and glucoamylase are macromolecular substances capable of decomposing starch, hydrolyzing the glycosidic bonds in starch, and decomposing starch into smaller sugars (such as maltose, glucose, etc.). Among them, α-amylase is an endo-amylase, which randomly cuts the α-1,4 glycosidic bonds in the starch molecule to generate shorter sugar chains; while glucoamylase is an exo-amylase, which mainly hydrolyzes α-1,4 and α-1,6 glycosidic bonds to further decompose starch into glucose. The synergistic action of the two helps to form a stable porous cassava starch structure.

[0024] In some embodiments of the present invention, in step S2, the enzymatic hydrolysis reaction specifically includes: mixing the cassava starch with water to prepare a 20 - 40% (w / v) cassava starch solution, then adjusting the pH value to 5 - 5.5, adding the α - amylase and the glucoamylase, and reacting.

[0025] In some embodiments of the present invention, in step S2, the addition concentration of the α - amylase is 0.5% - 1.5% (w / v). For example: it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4% or 1.5% (w / v).

[0026] In some embodiments of the present invention, in step S2, the addition concentration of the glucoamylase is 0.5% - 1.5% (w / v). For example: it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4% or 1.5% (w / v).

[0027] Adopting the preferred amylase concentration range of the present invention helps to form a better porous structure. However, too high an amylase content will excessively cleave the α - 1,4 - glycosidic bonds in the starch molecules, causing the starch to lose its original granular structure and network support ability, and generating a large amount of low - molecular - weight short - chain dextrins, maltose and glucose, resulting in difficulty in forming a sufficient network structure to support the gas expansion during the subsequent puffing process. At the same time, short - chain dextrins and low - molecular - weight sugars are prone to caramelization reactions at high temperatures, leading to a hardening of the product texture, an inability to form a crispy puff texture, and an easy coarsening or stickiness of the taste.

[0028] In some embodiments of the present invention, the enzymatic hydrolysis temperature is 55 - 70°C, and the enzymatic hydrolysis time is 0.5 - 1.5 h. For example: the enzymatic hydrolysis temperature can be 55°C, 58°C, 60°C, 63°C, 65°C, 68°C or 70°C; the enzymatic hydrolysis time can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4 or 1.5 h.

[0029] In some embodiments of the present invention, in step S3, the mass ratio of the soy protein isolate particles to the porous cassava starch particles is 1 - 3:1. For example: it can be 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1 or 3:1.

[0030] In some embodiments of the present invention, in step S3, during the wet mixing process, the addition ratio of water in the raw materials is 20% - 30%. For example, it can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%.

[0031] In some embodiments of the present invention, in step S3, the raw materials further include resistant starch - polyphenol complex.

[0032] Adding resistant starch to the raw materials of soy protein particles can improve the anti - digestibility of soy protein particles and increase satiety. The interaction between resistant starch and polyphenolic substances further changes the ordered multi - size structure of resistant starch, reduces the contact with enzymes, and thus improves the anti - digestibility. In addition, based on the antioxidant effect of polyphenolic substances, adding them as preparation raw materials also helps to extend the storage of soy protein particles and prevent softening.

[0033] In some embodiments of the present invention, the preparation method of the resistant starch - polyphenol complex includes: mixing the resistant starch and polyphenolic substances in a solvent and reacting to obtain it.

[0034] In some embodiments of the present invention, the polyphenolic substances include at least one of tea polyphenols, gallic acid, catechins, procyanidins, chlorogenic acid, soy isoflavones, epicatechin, vanillic acid, dihydroquercetin.

[0035] In some embodiments of the present invention, in step S3, the twin - screw extrusion process is provided with five - stage temperature control, and the temperature setting ranges are respectively: 45 - 55°C, 60 - 70°C, 105 - 110°C, 125 - 135°C, 145 - 160°C. For example, the five - stage temperature control can be set to 45°C, 60°C, 105°C, 125°C, 145°C, or 50°C, 65°C, 110°C, 130°C, 150°C, or 55°C, 70°C, 110°C, 130°C, 155°C, or 55°C, 70°C, 110°C, 135°C, 160°C. Temperature is one of the key factors affecting the degree of puffing. When the extrusion temperature is too high, the moisture in the material will evaporate rapidly, resulting in a more obvious puffing effect. However, the excessive puffing caused by too high temperature makes the soy protein particles fragile. A lower temperature may lead to incomplete puffing, with dense and hard particles, affecting their taste and product quality. The optimized high temperature of the present invention can improve the plasticity of soy protein particles, enabling them to expand fully during the extrusion process and form a loose particle structure.

[0036] In the second aspect of the present invention, there is provided a kind of soy protein particle, which is prepared by using the preparation method of the soy protein particle as described in any item of the first aspect.

[0037] The soy protein particles according to the embodiments of the present invention have at least the following beneficial effects: The soy protein particles prepared by the present invention have an excellent crispy texture and are storage-resistant, which helps to maintain the crispy texture.

[0038] In some embodiments of the present invention, the particle size of the soy protein particles is 2 - 8 mm. For example, it can be 2, 3, 4, 5, 6, 7, or 8 mm.

[0039] In the third aspect of the present invention, there is provided a method for preparing the soy protein particles according to any one of the first aspect or the application of the soy protein particles according to the second aspect in any one of the following: A) Preparing a solid beverage; B) Preparing an expanded food; C) Preparing a compressed biscuit; D) Preparing a protein bar.

[0040] In the fourth aspect of the present invention, there is provided a high-satiety double-layer protein bar, comprising a particle layer and a powder layer; Wherein the raw materials for preparing the particle layer include at least one of the soy protein particles as described in the second aspect, and vegetable and cereal crispy pieces, fruit and vegetable particles, cereal particles, nuts, chocolate, first composite protein, first fruit and vegetable powder, first miscellaneous grain powder, dietary fiber powder, first oil, first flavoring powder, and first food additive.

[0041] The high-satiety double-layer protein bar according to the embodiments of the present invention has at least the following beneficial effects: The high-satiety double-layer protein bar prepared with the soy protein particles of the present invention has an excellent crispy texture and is storage-resistant. The high-satiety double-layer protein bar of the present invention adds soy protein particles with excellent crispy texture and moisture absorption resistance, and is combined with components such as vegetable and cereal crispy pieces, fruit and vegetable particles, cereal particles, nuts, chocolate, composite protein, miscellaneous grains, or dietary fiber, which helps to extend the digestion time of the protein bar in the stomach, delay the gastric emptying rate, and prolong the satiety.

[0042] In some embodiments of the present invention, in the high-satiety double-layer protein bar, the particle size of the soy protein particles is 2 - 8 mm. For example, it can be 2, 3, 4, 5, 6, 7, or 8 mm.

[0043] In some embodiments of the present invention, the addition amount of the soy protein particles in the high-satiety double-layer protein bar is 3 - 20%. For example, it can be 3%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%.

[0044] In some embodiments of the present invention, the first composite protein comprises one or a combination of several of soy protein isolate, whey protein concentrate, milk protein concentrate, phycocyanin, skim milk powder, and calcium caseinate.

[0045] In some embodiments of the present invention, the vegetable and grain brittle pieces comprise one or a combination of several of oatmeal, high-protein vegetable and grain flakes, and savory vegetable and grain granules.

[0046] In some embodiments of the present invention, the fruit and vegetable particles comprise one or a combination of several of diced yellow peaches, diced purple sweet potatoes, diced mangoes, coconut shreds, diced passion fruits, dried cranberries, raisins, coconut brittle pieces, and coconut flakes.

[0047] In some embodiments of the present invention, the grain particles comprise one or a combination of several of quinoa balls, wheat bran balls, oat crisps, and puffed grains.

[0048] In some embodiments of the present invention, the dietary fiber powder comprises one or a combination of several of barley grass powder, pea fiber powder, soy dietary fiber powder, and resistant dextrin.

[0049] In some embodiments of the present invention, the raw materials for preparing the powder layer comprise at least one of a second composite protein, a second fruit and vegetable powder, a second miscellaneous grain powder, a second oil, a second flavor powder, and a second food additive.

[0050] In some embodiments of the present invention, the second composite protein comprises one or a combination of several of soy protein isolate, whey protein concentrate, milk protein concentrate, phycocyanin, skim milk powder, and calcium caseinate.

[0051] In some embodiments of the present invention, the first fruit and vegetable powder and the second fruit and vegetable powder are independently selected from one or a combination of several of coconut powder, coconut milk powder, green grape juice powder, peach powder, beet powder, honeydew melon juice powder, red beet juice powder.

[0052] In some embodiments of the present invention, the first miscellaneous grain powder and the second miscellaneous grain powder are independently selected from one or a combination of several of purple sweet potato powder, taro powder, soybean powder, and oat powder.

[0053] In some embodiments of the present invention, the first oil and the second oil comprise vegetable oil, and the vegetable oil comprises one or a combination of several of peanut oil, rapeseed oil, and sunflower oil.

[0054] In some embodiments of the present invention, the first flavor powder and the second flavor powder are independently selected from one or a combination of several of cocoa powder, coffee powder, oolong tea powder, black tea powder, matcha powder, jasmine tea powder, gardenia powder, cheese powder, and edible salt.

[0055] In some embodiments of the present invention, the first food additive and the second food additive are independently selected from one or more combinations of sugar, sugar alcohol, maltodextrin, arabic gum, food flavor, edible pigment, emulsifier.

[0056] In some embodiments of the present invention, the sugar includes one or more combinations of fructooligosaccharide, isomaltooligosaccharide syrup, polydextrose, caramel syrup.

[0057] In some embodiments of the present invention, the sugar alcohol includes maltitol solution and / or sorbitol solution.

[0058] In some embodiments of the present invention, the edible pigment includes β-carotene powder and / or turmeric powder.

[0059] In some embodiments of the present invention, the emulsifier includes phospholipid and / or glycerol.

[0060] In some embodiments of the present invention, the high satiety double-layer protein bar further contains flavor materials.

[0061] Preferably, the flavor materials are wrapped on the outer surface of the high satiety double-layer protein bar.

[0062] In some embodiments of the present invention, the flavor materials include at least one of yogurt flavor materials, milk flavor materials, cocoa flavor materials.

[0063] In some embodiments of the present invention, the preparation raw materials of the yogurt flavor materials include one or more combinations of vegetable oil, maltitol, whole milk powder, resistant dextrin, fermented milk powder, phospholipid.

[0064] In some embodiments of the present invention, the preparation raw materials of the milk flavor materials include one or more combinations of vegetable oil, maltitol, whole milk powder, phospholipid.

[0065] In some embodiments of the present invention, the preparation raw materials of the cocoa flavor materials include one or more combinations of vegetable oil, maltitol, cocoa powder, resistant dextrin, anhydrous butter, phospholipid.

[0066] In the fifth aspect of the present invention, there is provided a preparation method of the high satiety double-layer protein bar as described in the fourth aspect, which includes: S11. Mix the preparation raw materials of the particle layer, and press and mold them to obtain a particle layer; S12. Mix the preparation raw materials of the powder layer, and press and mold them to obtain a powder layer; S13. After laminating the particle layer and the powder layer, press and mold them to obtain the product.

[0067] In some embodiments of the present invention, after the step S13 is formed, coating the flavor material is further included.

[0068] In some embodiments of the present invention, the flavor material includes at least one of a yogurt flavor material, a milk flavor material, and a cocoa flavor material.

[0069] Other features and advantages of the present invention will be described in the subsequent specification. Brief Description of the Drawings

[0070] The present invention will be further described below in conjunction with the drawings and embodiments, where: Figure 1 is the evaluation result of the in vitro digestion characteristics of the present invention. Detailed Embodiments

[0071] The concept of the present invention and the technical effects produced will be clearly and completely described below in conjunction with the embodiments to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present invention.

[0072] The terms "preferably", "more preferably", etc. in the present invention refer to the embodiments of the present invention that can provide certain beneficial effects in certain cases. However, in the same case or other cases, other embodiments may also be preferred. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present invention.

[0073] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum value and the maximum value of the range, as well as each value between such minimum value and maximum value. Further, when the range refers to an integer, it includes each integer between the minimum value and the maximum value of the range. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0074] In the description of the present invention, the reference term "and / or" includes all and any combinations of one or more of the related listed items.

[0075] In the description of the present invention, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0076] In an embodiment of the present invention, the cassava starch is food-grade cassava starch, purchased from Shengxuan Chemical Industry, with the product number YS-3045. The enzyme activity of α-amylase is about 2000 U / g, and the CAS is 9000-90-2; the enzyme activity of glucoamylase is about 2000 U / g.

[0077] In an embodiment of the present invention, "w / v" is the mass-volume ratio, with the unit of g / mL.

[0078] For those not specifying specific conditions in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0079] (I) Preparation process of soy protein particles Example 1 This example provides a preparation process of soy protein particles, which includes the following steps: Step S1: Add pure water to 150 parts of soy protein isolate powder, stir evenly to prepare a soy protein isolate solution with a concentration of 15% (w / v), and then gradually add 0.5 M hydrochloric acid drop by drop while stirring to adjust the pH value of the system to 3.0 to obtain a soy protein isolate dispersion; Step S2: Place the soy protein isolate dispersion prepared in Step S1 under ultrasonic conditions with a power of 150 W and a frequency of 30 kHz for 15 min, then adjust the pH value to 7 with 0.5 M sodium hydroxide solution, mix well, and then perform freeze-drying. After drying is completed, soy protein isolate particles are obtained and reserved; Step S3: Weigh 300 parts of cassava starch and disperse it in pure water to prepare a cassava starch solution with a concentration of 30% (w / v), adjust the pH value to 5.0, then add 1% (w / v) α-amylase and 1% (w / v) glucoamylase, and enzymatically hydrolyze at 60°C for 1 h. After freeze-drying, porous cassava starch particles are obtained; Step S4: Mix the soy protein isolate particles obtained in Step S2 and the porous tapioca starch particles obtained in Step S3 in a mass ratio of 3:2, add 25% purified water, stir evenly, and then pour them into a twin-screw extruder for extrusion puffing. The twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50°C, 65°C, 110°C, 130°C, 150°C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h. Step S5: Cut the extruded and puffed soy protein product obtained in Step S4 with a high-speed stainless steel cutter to obtain granular puffed products, and then place them in an oven at 45°C for hot air drying to obtain soy protein particles with a particle size of 2 - 4 mm and a water content of about 5%.

[0080] Example 2 This example provides a preparation process for soy protein particles, which is different from Example 1 in that: in Step S1, the pH value is adjusted to 11.0, and the other conditions are the same. The specific steps are as follows: Step S1: Add purified water to 150 parts of soy protein isolate powder, stir evenly to prepare a soy protein isolate solution with a concentration of 15% (w / v), and then gradually add 0.5 M sodium hydroxide drop by drop while stirring to adjust the pH value of the system to 11.0 to obtain a soy protein isolate dispersion.

[0081] Step S2: Place the soy protein isolate dispersion prepared in Step S1 under ultrasonic conditions with a power of 150 W and a frequency of 30 kHz for 15 min, then adjust the pH value to 7 with 0.5 M hydrochloric acid, mix well, and then perform freeze-drying. After the drying is completed, obtain soy protein isolate particles for standby.

[0082] Step S3: Weigh 300 parts of tapioca starch and disperse it in purified water to prepare a tapioca starch solution with a concentration of 30% (w / v), adjust the pH value to 5.0, then add 1% (w / v) α-amylase and 1% (w / v) glucoamylase, and enzymatically hydrolyze at 60°C for 1 h. After freeze-drying, obtain porous tapioca starch particles.

[0083] Step S4: Mix the soy protein isolate particles obtained in Step S2 and the porous tapioca starch particles obtained in Step S3 in a mass ratio of 3:2, add 25% purified water, stir evenly, and then pour them into a twin-screw extruder for extrusion puffing. The twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50°C, 65°C, 110°C, 130°C, 150°C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0084] Step S5: Cut the extruded and expanded soybean protein bulking agent obtained in step S4 above with a high-speed stainless steel cutter to obtain granular bulking agent, and then place it in an oven at 45 °C for hot air drying to obtain soybean protein particles with a particle size of 2 - 4 mm and a water content of about 5%.

[0085] Example 3 This example provides a preparation process of soybean protein particles, which is different from Example 1 in that: in step S2, the ultrasonic power is 120 W, and the other conditions are the same. The specific steps are as follows: Step S1: Add pure water to 150 parts of soy protein isolate powder, stir evenly to prepare a soy protein isolate solution with a concentration of 15% (w / v), and then gradually add hydrochloric acid with a concentration of 0.5 M while stirring to adjust the pH value of the system to 3.0 to obtain a soy protein isolate dispersion.

[0086] Step S2: Place the soy protein isolate dispersion prepared in step S1 under ultrasonic conditions with a power of 120 W and a frequency of 30 kHz for 15 min, then adjust the pH value to 7 with 0.5 M sodium hydroxide solution, mix well, and then perform freeze-drying. After the drying is completed, obtain soy protein isolate particles for standby.

[0087] Step S3: Weigh 300 parts of tapioca starch and disperse it in pure water to prepare a tapioca starch solution with a concentration of 30% (w / v), adjust the pH value to 5.0, then add 1% (w / v) α-amylase and 1% (w / v) glucoamylase, and enzymatically hydrolyze at 60 °C for 1 h. After freeze-drying, obtain porous tapioca starch particles.

[0088] Step S4: Mix the soy protein isolate particles obtained in step S2 and the porous tapioca starch particles obtained in step S3 above at a mass ratio of 3:2, add 25% pure water, stir evenly, and then pour it into a twin-screw extruder for extrusion and expansion. Among them, the twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50 °C, 65 °C, 110 °C, 130 °C, 150 °C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0089] Step S5: Cut the extruded and expanded soybean protein bulking agent obtained in step S4 above with a high-speed stainless steel cutter to obtain granular bulking agent, and then place it in an oven at 45 °C for hot air drying to obtain soybean protein particles with a particle size of 2 - 4 mm and a water content of about 5%.

[0090] Example 4 This embodiment provides a preparation process of soy protein particles, which is different from Embodiment 1 in that: in step S2, the ultrasonic power is 200 W, and the other conditions are the same. The specific steps are as follows: Step S1: Add pure water to 150 parts of soy protein isolate powder, stir evenly to prepare a soy protein isolate solution with a concentration of 15% (w / v), and then dropwise add 0.5 M hydrochloric acid while stirring to adjust the pH value of the system to 3.0 to obtain a soy protein isolate dispersion.

[0091] Step S2: Place the soy protein isolate dispersion prepared in step S1 under ultrasonic conditions with a power of 200 W and a frequency of 30 kHz for 15 min, then adjust the pH value to 7 with 0.5 M sodium hydroxide solution, mix well, and then perform freeze-drying. After the drying is completed, soy protein isolate particles are obtained and reserved for use.

[0092] Step S3: Weigh 300 parts of tapioca starch and disperse it in pure water to prepare a tapioca starch solution with a concentration of 30% (w / v), adjust the pH value to 5.0, then add 1% (w / v) α-amylase and 1% (w / v) glucoamylase, and enzymatically hydrolyze at 60 °C for 1 h. After freeze-drying, porous tapioca starch particles are obtained.

[0093] Step S4: Mix the soy protein isolate particles obtained in step S2 and the porous tapioca starch particles obtained in step S3 at a mass ratio of 3:2, add 25% pure water, stir evenly, and then pour them into a twin-screw extruder for extrusion puffing. Among them, the twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50 °C, 65 °C, 110 °C, 130 °C, 150 °C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0094] Step S5: Cut the extruded and puffed soy protein obtained in step S4 with a high-speed stainless steel cutter to obtain granular puffed products, and then place them in an oven at 45 °C for hot air drying to obtain soy protein particles with a particle size of 2 - 4 mm and a water content of about 5%.

[0095] Embodiment 5 This embodiment provides a preparation process of soy protein particles, which is different from Embodiment 1 in that: in step S2, spray drying is used, and the other conditions are the same. The specific steps are as follows: Step S1: Add pure water to 150 parts of soy protein isolate powder, stir evenly to prepare a soy protein isolate solution with a concentration of 15% (w / v), and then dropwise add 0.5 M hydrochloric acid while stirring to adjust the pH value of the system to 3.0 to obtain a soy protein isolate dispersion.

[0096] Step S2: Place the soy protein isolate dispersion obtained in Step S1 under ultrasonic treatment at a power of 150 W and a frequency of 30 kHz for 15 min. Then, adjust the pH value to 7 with 0.5 M sodium hydroxide solution, mix well, and then perform spray drying. The inlet air temperature for drying is 110 °C and the outlet air temperature is 60 °C. After drying is completed, soy protein isolate particles are obtained and set aside for later use.

[0097] Step S3: Weigh 300 parts of tapioca starch and disperse it in pure water to prepare a tapioca starch solution with a concentration of 30% (w / v). Adjust the pH value to 5.0, then add 1% (w / v) α-amylase and 1% (w / v) glucoamylase, and enzymatically hydrolyze at 60 °C for 1 h. Then, obtain porous tapioca starch particles by freeze-drying.

[0098] Step S4: Mix the soy protein isolate particles obtained in Step S2 and the porous tapioca starch particles obtained in Step S3 in a mass ratio of 3:2, add 25% pure water, stir evenly, and then pour them into a twin-screw extruder for extrusion puffing. The twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50 °C, 65 °C, 110 °C, 130 °C, 150 °C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0099] Step S5: Use a high-speed stainless steel cutter to cut the extruded and puffed soy protein obtained in Step S4 to obtain granular puffed products, and then place them in an oven at 45 °C for hot air drying to obtain soy protein particles with a particle size of 2 - 4 mm and a water content of about 5%.

[0100] Example 6 This example provides a preparation process of soy protein particles, which is different from Example 1 in that: in Step S3, 1.5% (w / v) α-amylase and 0.5% (w / v) glucoamylase are added, and the other conditions are the same. The specific steps are as follows: Step S1: Add pure water to 150 parts of soy protein isolate powder, stir evenly to prepare a soy protein isolate solution with a concentration of 15% (w / v), and then gradually add 0.5 M hydrochloric acid dropwise while stirring to adjust the pH value of the system to 3.0 to obtain a soy protein isolate dispersion.

[0101] Step S2: Place the soybean protein isolate dispersion obtained in Step S1 under ultrasonic conditions with a power of 150 W and a frequency of 30 kHz for 15 min. Then adjust the pH value to 7 with 0.5 M sodium hydroxide solution, mix well, and then perform freeze-drying. After the drying is completed, soybean protein isolate particles are obtained and reserved for use.

[0102] Step S3: Weigh 300 parts of cassava starch and disperse it in pure water to prepare a cassava starch solution with a concentration of 30% (w / v). Adjust the pH value to 5.0, then add 1.5% (w / v) α-amylase and 0.5% (w / v) glucoamylase, and enzymatically hydrolyze at 60 °C for 1 h. After freeze-drying, porous cassava starch particles are obtained.

[0103] Step S4: Mix the soybean protein isolate particles obtained in Step S2 and the porous cassava starch particles obtained in Step S3 at a mass ratio of 3:2, add 25% pure water, stir evenly, and then pour them into a twin-screw extruder for extrusion expansion. The twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50 °C, 65 °C, 110 °C, 130 °C, 150 °C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0104] Step S5: Use a high-speed stainless steel cutter to cut the extruded and expanded soybean protein obtained in Step S4 to obtain granular expanded products, and then place them in an oven at 45 °C for hot air drying to obtain soybean protein particles with a particle size of 2 - 4 mm and a water content of about 5%.

[0105] Example 7 This example provides a preparation process for soybean protein particles, which is different from Example 1 in that: in Step S3, the pH value of the cassava starch solution is adjusted to 5.5, and at the same time, the mixing ratio of the soybean protein isolate particles and the porous cassava starch particles in Step S4 is adjusted to 1:1, and the amount of water added is adjusted accordingly. The specific steps are as follows: Step S1: Add pure water to 150 parts of soybean protein isolate powder, stir evenly to prepare a soybean protein isolate solution with a concentration of 15% (w / v), and then gradually add 0.5 M hydrochloric acid dropwise while stirring to adjust the pH value of the system to 3.0 to obtain a soybean protein isolate dispersion.

[0106] Step S2: Place the soybean protein isolate dispersion obtained in Step S1 under ultrasonic conditions with a power of 150 W and a frequency of 30 kHz for 15 min. Then adjust the pH value to 7 with 0.5 M sodium hydroxide solution, mix well, and then perform freeze-drying. After the drying is completed, soybean protein isolate particles are obtained and reserved for use.

[0107] Step S3: Weigh 300 parts of cassava starch and disperse it in pure water to prepare a cassava starch solution with a concentration of 30% (w / v). Adjust the pH value to 5.5, then add 1% (w / v) α-amylase and 1% (w / v) glucoamylase, and enzymatically hydrolyze at 60 °C for 1 h. After freeze-drying, porous cassava starch granules are obtained.

[0108] Step S4: Mix the soy protein isolate granules obtained in Step S2 and the porous cassava starch granules obtained in Step S3 at a mass ratio of 1:1, add 30% of pure water, stir evenly, and then pour them into a twin-screw extruder for extrusion puffing. The twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50 °C, 65 °C, 110 °C, 130 °C, 150 °C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0109] Step S5: Use a high-speed stainless steel cutter to cut the soy protein puffed product after extrusion puffing in Step S4 to obtain granular puffed products, and then place them in an oven at 45 °C for hot air drying to obtain soy protein granules with a particle size of 2 - 4 mm and a water content of about 5%.

[0110] Example 8 This example provides a preparation process for soy protein granules, which is different from Example 1 in that: in Step S4, a resistant starch-tea polyphenol complex is added, and the other steps are the same. The specific steps are as follows: Step S1: Add pure water to 150 parts of soy protein isolate powder, stir evenly to prepare a soy protein isolate solution with a concentration of 15% (w / v), and then gradually add 0.5 M hydrochloric acid dropwise while stirring to adjust the pH value of the system to 3.0 to obtain a soy protein isolate dispersion.

[0111] Step S2: Place the soy protein isolate dispersion prepared in Step S1 under ultrasonic conditions with a power of 150 W and a frequency of 30 kHz for 15 min, then adjust the pH value to 7 with 0.5 M sodium hydroxide solution, mix well, and then perform freeze-drying. After drying is completed, soy protein isolate granules are obtained for standby.

[0112] Step S3: Weigh 300 parts of cassava starch and disperse it in pure water to prepare a cassava starch solution with a concentration of 30% (w / v). Adjust the pH value to 5.0, then add 1% (w / v) α-amylase and 1% (w / v) glucoamylase, and enzymatically hydrolyze at 60 °C for 1 h. After freeze-drying, porous cassava starch granules are obtained.

[0113] Step S4: Mix the soy protein isolate particles obtained in Step S2, the porous tapioca starch particles obtained in Step S3, and the resistant starch-tea polyphenol complex in a mass ratio of 3:2:1, add 25% pure water, stir evenly, and then pour it into a twin-screw extruder for extrusion expansion. The twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50 °C, 65 °C, 110 °C, 130 °C, 150 °C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0114] Step S5: Cut the extruded and expanded soy protein product obtained in Step S4 with a high-speed stainless steel cutter to obtain granular expanded products, and then place them in an oven at 45 °C for hot air drying to obtain soy protein particles with a particle size of 2-4 mm and a water content of about 5%.

[0115] Among them, the preparation method of the resistant starch-tea polyphenol complex is as follows: Disperse resistant starch RS2 (purchased from Beijing Xiangyu, product number Xiangyu 1945) in an appropriate amount of water, stir evenly to prepare a 30% (w / v) starch suspension, and then heat it to 100 °C and continuously stir to make it completely gelatinized. After gelatinization, set aside.

[0116] Dissolve tea polyphenols in deionized water with a pH value of 7.5 to prepare a 5% (w / v) tea polyphenol solution. Then slowly add the tea polyphenol solution to the resistant starch solution, stir while adding, and place it in a 65 °C constant temperature water bath for a certain reaction time of 2 h to make the polyphenols fully bind to the resistant starch. After the reaction is completed, centrifuge the reaction mixture, collect the complex precipitate, wash the precipitate with deionized water to remove the unbound polyphenols, centrifuge again, collect the precipitate, and obtain it after freeze-drying.

[0117] Comparative Example 1 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is as follows: There are differences in the preparation of soy protein isolate particles in Step S1 and Step S2, specifically as follows: Step S1: Add pure water to 150 parts of soy protein isolate powder, stir evenly to prepare a 15% (w / v) soy protein isolate solution.

[0118] Step S2: Place the soy protein isolate solution prepared in Step S1 under ultrasonic conditions with a power of 150 W and a frequency of 30 kHz for 15 min, and then perform freeze-drying. After drying is completed, obtain soy protein isolate particles for standby.

[0119] The remaining steps are the same as those in Example 1.

[0120] Comparative Example 2 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is that: the ultrasonic treatment power in step S2 is different, and the ultrasonic treatment power in this comparative example is 250 W. The remaining steps are the same.

[0121] Comparative Example 3 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is that: the soy protein isolate is not subjected to ultrasonic cavitation treatment, that is, in step S4, soy protein isolate powder is directly used to replace soy protein particles. The remaining steps are the same.

[0122] Comparative Example 4 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is that: α-amylase is replaced by β-amylase, and the remaining steps are the same.

[0123] Comparative Example 5 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is that: step S3 is different. Step 3 in this comparative example is: Weigh 300 parts of cassava starch and disperse it in pure water to prepare a cassava starch solution with a concentration of 30% (w / v), adjust the pH value to 5.0, and add 2% (w / v) glucoamylase and carry out an enzymatic hydrolysis reaction at 60 °C for 1 h, and then obtain porous cassava starch particles after freeze-drying. The remaining steps are the same.

[0124] Comparative Example 6 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is that: step S3 is different. Step 3 in this comparative example is: Weigh 300 parts of cassava starch and disperse it in pure water to prepare a cassava starch solution with a concentration of 30% (w / v), adjust the pH value to 5.0, then add 2% (w / v) α-amylase, and carry out enzymatic hydrolysis at 60 °C for 1 h, and then obtain porous cassava starch particles after freeze-drying. The remaining steps are the same.

[0125] Comparative Example 7 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is that: the cassava starch is not subjected to enzymatic hydrolysis treatment, and in step S4, soy protein particles and cassava starch are mixed at a mass ratio of 3:2. The remaining steps are the same.

[0126] Comparative Example 8 This comparative example provides a preparation process of soy protein particles, and the difference from Example 1 is that: the soy protein isolate powder and cassava starch are not pretreated, and the specific preparation process is as follows: Step S1: Mix soy protein isolate powder and tapioca starch in a mass ratio of 3:2, add 25% pure water, stir evenly, and then pour it into a twin-screw extruder for extrusion and puffing. The twin-screw extrusion uses five-stage temperature control, and the temperature settings for each stage are: 50°C, 65°C, 110°C, 130°C, and 150°C; the screw speed is 180 rpm, and the feeding speed is 12 kg / h.

[0127] Step S2: Cut the soy protein puffed product after extrusion and puffing in the above step S4 with a high-speed stainless steel cutter to obtain granular puffed products, and then place them in an oven at 45°C for hot air drying to obtain soy protein particles with a water content of about 5%.

[0128] Test Example 1: Performance Test of Soy Protein Particles In this example, the crispness of the soy protein particles prepared in the above examples and comparative examples was detected, as follows: (1) Crispness test: Use the HDP-BSK probe of the TA-XT2i type physical property tester to perform shear tests on the soy protein particles prepared in Examples 1-8 and Comparative Examples 1-8 above. Each group is repeated 8 times, and the test mode is Return to start; the speeds before, during, and after the test are 5 mm / s, 1 mm / s, and 5 mm / s respectively, the shear ratio is 100%, the trigger force is 10 g, and the data acquisition speed is 200 pps. During the test, the maximum force received during the downward pressing of the probe is recorded as F m , and the corresponding abscissa is recorded as S E (i.e., distance / mm), and the force corresponding to the vertex of the first negative peak (concave peak) after the maximum force is recorded as F q , and the corresponding abscissa is recorded as S F , and its crispness is represented by the slope K1. The calculation formula is as follows: K1=(F m -F q ) / (S F -S E ).

[0129] When K1 < 10 kg / mm, it means that the sample has little brittleness or no brittleness; when 10 kg / mm < K1 < 100 kg / mm, it means that the sample has medium brittleness; when K1 > 100 kg / mm, it means that the sample has large brittleness.

[0130] Crispness loss rate: After testing the initial crispness of the test sample (denoted as K1), place the sample in a sealed container at a temperature of 25°C and a humidity of 50% for 5 days, take out the sample, and detect the crispness of the sample again (denoted as K2), and then calculate the crispness retention rate. The calculation formula is: Crispness loss rate = 1 - (K2 / K1 × 100%).

[0131] The crispness and test results are shown in Table 1.

[0132] Table 1: Test Results of Soy Protein Particle Properties

[0133] The results show that the soy protein particles prepared by the preparation method of the embodiment of the present invention have excellent crispness, the K value reaches more than 270 kg / mm, and have a good effect of maintaining the crisp feeling, where: The results of the influence of ultrasonic treatment and pH adjustment on soy protein isolate particles show that, compared with acidic treatment, alkaline conditions are more conducive to improving the stability and solubility of soy protein isolate particles (such as Examples 1 and 2). At the same time, ultrasonic treatment (150 W) combined with pH adjustment (3.0 → 7.0) can significantly improve the crispness and stability of soy protein particles (such as Examples 1 and Comparative Examples 1 and 3), presumably related to the improvement of the dissolution stability of soy protein isolate particles. Higher solubility helps soy protein isolate particles to better disperse on the surface and inside of porous cassava starch particles, making the puffing more uniform. However, higher ultrasonic treatment conditions are not conducive to maintaining crisp stability (such as Comparative Example 2), presumably because excessive ultrasonic treatment leads to excessive destruction of the structure of soy protein, and the interaction between protein molecules is enhanced, which is not conducive to the improvement of dispersibility and stability.

[0134] The results of the modification effect of enzymatic hydrolysis treatment on cassava starch show that the synergistic effect of α-amylase and glucoamylase helps to significantly improve the crispness and moisture absorption resistance. Presumably, the specific surface area of cassava starch particles increases after being treated with α-amylase and glucoamylase, which helps to increase the contact with soy protein isolate particles. After puffing treatment, the crystal structure of porous cassava starch particles is further disintegrated, and the hydrophobic groups of soy protein isolate particles dispersed inside the porous cassava starch particles are also exposed under high temperature conditions, resulting in a decrease in their hydration ability, which is beneficial to maintaining the crisp taste of the particles. When α-amylase is replaced with β-amylase, the related properties decline, presumably related to the exo-enzyme nature of β-amylase.

[0135] Test Example 2: Evaluation of in vitro digestion characteristics In order to explore the influence of the treatment method of soy protein isolate particles and the enzymatic hydrolysis of cassava starch particles on the digestion performance of soy particle proteins, in this example, the in vitro digestion characteristics of soy protein particles prepared by the methods of Examples 1 and 8, and Comparative Examples 1, 3, 7, and 8 were evaluated by simulating the three digestion stages of the oral cavity, gastric juice, and pancreas in vitro. The specific method is as follows: Accurately weigh 5.00 g of soy protein particles, add 50 mL of deionized water, and treat them in a water bath at 37 °C for 5 min (stirring during the treatment process). Then, sequentially add 0.2 mL of 10% α-amylase, 1.5 mL of 10% pepsin, and 1.5 mL of 5% trypsin to initiate three digestion stages. At 0, 30, 60, 90, 120, 150, and 180 min, take 1 mL of the reaction solution, mix and dilute it with 4 mL of absolute ethanol, centrifuge (10,000 rpm, 5 min), take the supernatant, and use the DNS colorimetric method to measure the glucose concentration at different digestion stages, calculate the digestibility of starch at different time points, and plot the hydrolysis rate curve of the sample.

[0136] The test results are as Figure 1 shown. The results show that compared with those without ultrasonic treatment, pH adjustment, and enzymatic reaction treatment (Comparative Example 8), the soy protein particles prepared by the method of the present invention can slow down the digestibility of starch and have good digestion resistance. It is speculated that this is related to the soy protein isolate particles dispersed on the surface of porous cassava starch, and the soy protein isolate particles reduce the contact between the enzyme and porous cassava starch.

[0137] In addition, based on the above test results, it can also be analyzed that using the soy protein isolate particles prepared by the present invention and the porous cassava starch after enzymatic hydrolysis as raw materials to prepare expanded soy protein particles has a certain synergistic effect in improving digestion resistance. Adding them to protein bars helps to avoid drastic blood sugar fluctuations in the eating population and can better delay hunger.

[0138] (2) Application of soy protein particles in the preparation of protein bars Example 9: Raw coconut cocoa flavored double-layer protein bar (1) Double-layer protein bar This example provides a raw coconut cocoa flavored double-layer protein bar with high satiety, which comprises a particle layer, a powder layer, and a cocoa flavor material coated on its surface; wherein: The particle layer is composed of particle layer materials and particle layer syrup materials. Calculated by weight, the preparation raw materials of the particle layer materials include the following components: 3 parts of soy protein particles, 1 part of salty vegetable and grain particles, 1 part of rolled oats, 0.4 part of concentrated whey protein powder, 0.2 part of pea fiber powder, 0.5 part of cocoa powder, 1.5 parts of resistant dextrin, 0.05 part of edible essence; among them, the soy protein particles are prepared by the method of Example 1; The preparation raw materials of the particle layer syrup materials include the following components: 1.7 parts of maltitol solution, 1 part of isomaltooligosaccharide syrup, 0.2 part of polydextrose, 1.2 parts of white chocolate, 0.05 part of phospholipid, 0.5 part of glycerol, 0.5 part of vegetable oil, and an appropriate amount of water.

[0139] The powder layer is composed of powder layer materials and powder layer syrup materials. By weight, the preparation raw materials of the powder layer materials include the following components: 1.8 parts of soy protein isolate, 1.5 parts of concentrated whey protein powder, 0.08 part of calcium caseinate, 0.4 part of skim milk powder, 0.5 part of concentrated milk protein, 0.3 part of coconut shreds, 0.1 part of coconut milk powder, 0.05 part of edible essence; The preparation raw materials of the powder layer syrup materials include the following components: 2 parts of maltitol syrup, 1 part of polydextrose, 1 part of sorbitol solution, 0.05 part of phospholipid, 0.8 part of glycerol, 0.01 part of edible salt, appropriate amount of water.

[0140] The cocoa flavor materials are composed of vegetable oil, maltitol, cocoa powder, resistant dextrin, anhydrous butter, phospholipid, and food flavor.

[0141] (2)Preparation method of double-layer protein bar This example also provides a preparation process of the above-mentioned high-satiety coconut cocoa flavored double-layer protein bar, which specifically includes the following steps: S1. Accurately weigh the granule layer materials, granule layer syrup materials, powder layer materials, and powder layer syrup materials according to the above weight parts, and then heat-treat the granule layer syrup materials and powder layer syrup materials respectively to make them liquefy; S2. Mix the dissolved granule layer syrup materials with the granule layer materials, and use a molding machine to press to obtain the granule layer, and set aside; S3. Mix the dissolved powder layer syrup materials with the powder layer materials, and extrude to obtain the powder layer, and set aside; S4. Combine and mold the above-mentioned granule layer and powder layer, cut according to actual needs after cooling, and finally coat and spray the cocoa flavor materials (weight ratio is about 28%), and obtain the product after cooling.

[0142] Example 10: White peach oolong flavored double-layer protein bar This example provides a high-satiety white peach oolong flavored double-layer protein bar, which includes a granule layer and a powder layer, and a yogurt flavor material coated on its surface; among them: The granule layer is composed of granule layer materials and granule layer syrup materials. By weight, the preparation raw materials of the granule layer materials include the following components: 1 part of soy protein particles, 2.5 parts of oat flavored protein particles, 0.7 part of high-protein vegetable and cereal flakes, 0.1 part of beet powder, 0.2 part of concentrated milk protein, 0.2 part of soy protein isolate, 0.26 part of yellow peach cubes, 0.9 part of resistant dextrin, 0.3 part of peach powder, 0.1 part of maltodextrin, 0.05 part of edible essence; among them, the soy protein particles are prepared by the method of Example 1; The preparation raw materials of the granular layer syrup material include the following components: 1.5 parts of maltitol solution, 0.6 part of isomaltooligosaccharide syrup, 0.9 part of sorbitol solution, 0.35 part of oligofructose, 0.35 part of glycerol, 0.45 part of sunflower seed oil, 0.05 part of phospholipid, 0.05 part of arabic gum, and appropriate amount of water.

[0143] The powder layer is composed of powder layer material and powder layer syrup layer material. Calculated by weight parts, the preparation raw materials of its powder layer material include the following components: 1.8 parts of soy protein isolate powder, 2.5 parts of concentrated whey protein powder, 0.08 part of calcium caseinate, 0.3 part of concentrated milk protein, 0.13 part of instant oolong tea powder, 0.3 part of peach powder, 0.1 part of beet powder, 0.7 part of soy powder, 0.05 part of edible essence; The preparation raw materials of the powder layer syrup layer material include the following components: 1.7 parts of maltitol solution, 1.9 parts of isomaltooligosaccharide syrup, 0.35 part of oligofructose, 0.4 part of polydextrose, 0.45 part of sunflower seed oil, 0.35 part of glycerol, 0.05 part of phospholipid, 0.05 part of arabic gum, and appropriate amount of water.

[0144] The yogurt flavor material consists of vegetable oil, maltitol, whole milk powder, resistant dextrin, fermented milk powder, and phospholipid.

[0145] The preparation method of the above white peach oolong flavored double - layer protein bar refers to Example 9.

[0146] Detection Example 3: Sensory evaluation Randomly select 20 technicians in the food field, aged between 23 and 35 years old, and conduct food sensory evaluation training for them to elaborate on the scoring criteria for each index of the protein bar. Using flavor, texture, viscosity, and satiety as evaluation indexes, conduct sensory evaluation on the double - layer protein bars prepared in Example 9 and Example 10 above.

[0147] Among them, the sensory evaluation criteria are shown in Table 2.

[0148] Table 2: Sensory evaluation criteria

[0149] The results show that the comprehensive scores of the double - layer protein bars prepared with the soybean protein particles of the present invention are all above 95. The feedback results show that their texture is moderately hard and soft, the taste is sweet without being choking, and the texture is rich during chewing, with a crispy feeling, not strenuous to chew, not easy to stick to the teeth, having a good satiety, and being able to effectively delay hunger.

[0150] The above has described the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing soy protein particles, characterized in that, Comprising: S1. Ultrasonically treating a soy protein isolate dispersion, and drying to obtain soy protein isolate particles; S2. Mixing tapioca starch and amylase, performing an enzymatic hydrolysis reaction, and drying to obtain porous tapioca starch particles; S3. Using a twin-screw extrusion process to wet-mix raw materials including the soy protein isolate particles and the porous tapioca starch particles to prepare soy protein particles.

2. The preparation method according to claim 1, characterized in that, In step S1, the frequency of the ultrasonic treatment is 25 - 35 kHz; and / or, the power of the ultrasonic treatment is 120 - 200 W; and / or, the time of the ultrasonic treatment is 10 - 25 min; and / or, the concentration of the soy protein isolate dispersion is 1 - 15% (w / v); and / or, the initial pH value of the soy protein isolate dispersion is 1.5 - 3.5 or 10.0 - 12.0, and after the ultrasonic treatment, an operation of adjusting the pH value to 6.5 - 7.5 is further included.

3. The preparation method according to claim 1, characterized in that In step S2, the amylase includes α-amylase and glucoamylase.

4. The preparation method according to claim 1, wherein In step S3, the raw materials further include a resistant starch-polyphenol complex.

5. The preparation method according to any one of claims 1 to 4, characterized in that, In step S3, the twin-screw extrusion process is provided with five-stage temperature control, and the temperatures from the feeding end to the discharging end are successively: 45 - 55 °C, 60 - 70 °C, 105 - 110 °C, 125 - 135 °C, 145 - 160 °C.

6. A soy protein particle, characterized in that, Prepared by using the preparation method of the soy protein particles according to any one of claims 1 to 5.

7. Use of the preparation method of the soy protein particles according to any one of claims 1 to 5 or the soy protein particles according to claim 6 in any one of the following: A) Preparing a solid beverage; B) Preparing an expanded food; C) Preparing a compressed biscuit; D) Preparing a protein bar.

8. A double-layer protein bar with high satiety, characterized in that, Comprising a particle layer and a powder layer; wherein the raw materials for preparing the particle layer include the soy protein particles according to claim 6, and at least one of vegetable and cereal crispy pieces, fruit and vegetable particles, cereal particles, nuts, chocolate, first composite protein, first fruit and vegetable powder, first miscellaneous grain powder, dietary fiber powder, first oil, first flavor powder, first food additive.

9. The high satiety double-layer protein bar according to claim 8, wherein The raw materials for preparing the powder layer include at least one of second composite protein, second fruit and vegetable powder, second miscellaneous grain powder, second oil, second flavor powder, second food additive.

10. A method for preparing a high satiety double-layer protein bar as claimed in claim 8 or 9, characterized in that, Comprising: S11. Mixing the raw materials for preparing the particle layer, and pressing into a shape to obtain a particle layer; S12. Mixing the raw materials for preparing the powder layer, and pressing into a shape to obtain a powder layer; S13. Stacking the particle layer and the powder layer, and pressing into a shape to obtain the product.

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