Set of brine solutions and method for in-line processing of food products

Abstract

To provide a method for in-line processing of food products that enhances the control of product characteristics of a coating material during the manufacture and the further life stages of the food products.SOLUTION: The present invention relates to a set of brine solutions for use in a method for in-line processing of food products, the method comprising the steps of a) co-extruding food dough into a flow of co-extruded food products having a protein-containing coating or a hybrid coating of a protein and a polymer, and b) subjecting the flow of co-extruded food products to a food product strengthening step. The food product strengthening step comprises the step of subjecting the flow of food products to a first brine solution comprising a salt solubilized in an aqueous medium, and a second brine solution comprising a buffer salt solubilized in an aqueous medium. The present invention further relates to a method for in-line processing of food products using the set of brine solutions of the present invention and a lactate salt comprising a brine solution.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a set of brine solutions and a method for in-line processing of food products using the set of brine solutions of the present invention.The present invention further relates to a brine solution having improved pH setting properties, a system for in-line processing of food products using the method of the present invention, and the use of the set of brine solutions of the present invention in a method for in-line processing of food products. [Background technology]

[0002] The method of co-extrusion in food products is generally known and is described inter alia in Dutch patent NL6909339. This description describes the coating of food dough strands with a casing layer of protein, e.g. collagen, using co-extrusion. After extrusion, the coated strands are guided for strengthening purposes through a coagulation bath. Under the influence of the coagulation solution, the protein coagulates and / or precipitates and the casing layer is strengthened. In this way, a food dough strand is formed which is at least partially coated with a strong casing layer of protein, i.e. collagen containing casing.

[0003] A drawback of the known methods is that the properties of the casing material, and therefore the processability of the food product, may change during the production of a co-extruded food product stream, i.e. a stream of individual sausages, strands of food products or a stream of sausages connected together (head-tail connections). The changes in the properties of the casing material are difficult to predict. Moreover, the changes in the properties of the casing material are irreversible. Thus, once the properties of the casing material change, the food product stream can no longer be processed to obtain a final food product, i.e. a sausage, of acceptable quality.

[0004] A particular drawback of known methods of using proteins or proteins containing viscous gelling agents as casing materials for the co-extrusion of elongated food products is the uncontrollable characteristics of the final food product, especially the surface state. It has been observed that by changing the process settings after the co-extrusion of the food dough strands and the casing material, the properties of the protein casing material can be irreversibly altered. Such changes can include changes in the surface properties of the casing material related to the surface smoothness of the food product, i.e. the "look-and-feel" of the food product. By changing the process settings after co-extrusion in subsequent processing steps such as brining, separating, crimping, smoking, drying, packaging, cooking and / or chilling the co-extruded elongated food product, the obtained food product can be uncontrollably altered to have an undesirable surface state, e.g. a sticky, uneven and / or dirty surface, instead of the normally desired smooth, good looking and stable surface. Such uncontrollable and irreversible changes in surface properties may result in poorer processability of the food product stream, so that the food product stream (or at least a portion of the food product stream) may even have to be discarded. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Dutch Patent Application Publication No. 6909339 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above, there is a need for increased control over the production of coextruded food products, and more specifically, increased control over the product properties of the coating (e.g., casing) materials during the manufacturing and further life stages of the food product. [Means for solving the problem]

[0007] The present invention provides for this purpose a set of brine solutions comprising a first and a second brine solution for use in a method for in-line processing of food products, said method comprising the steps of co-extruding a food dough into a co-extruded food product stream having a protein-containing coating or a protein-polymer hybrid coating, and subjecting the co-extruded food product stream to a food product fortification step, said food product fortification step comprising the steps of i) subjecting the food product stream to a coating moisture content reduction step using a first brine solution, said first brine solution comprising a salt solubilized in an aqueous medium, and then subjecting the food product stream to ii) a coating pH fixing step using a second brine solution, said second brine solution comprising a buffer salt solubilized in an aqueous medium. It has been found that unexpected irreversible changes in the processability and coating properties of co-extruded elongated food products are strongly dependent on the physical state of the protein or protein-containing hybrid coating. As a result, by controlling the physical state of the protein, changes in coating properties such as the smoothness of the coating surface can be controlled, i.e. prevented. In particular, it has been found that by providing a brine solution set having coating moisture content reducing properties on one end and coating pH setting or buffering properties on the other end, not only can the pH of the brine solution be maintained over extended periods of time, but the pH of the coating of the food product stream can also be maintained during further processing of the food product stream, thus providing an improved method whereby the physical state of the proteins is controlled in a more sustainable and reliable manner, i.e., significantly increasing the processability of the food product stream. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] With regard to the physical state of the protein, it is noted that such physical state may comprise three types of physical states: crystalline phase, helical phase, and random coil phase. It has been found that when a protein in helical or crystalline form is converted to a protein having a random coil form, an irreversible change in coating properties is expected. Proteins comprising food product coatings containing proteins in helical or crystalline form are characterized by a smooth, attractive appearance and / or a stable surface, whereas proteins comprising food product coatings containing proteins in random coil form exhibit a more sticky, uneven and / or dirty surface. As a result, in certain embodiments of the method of the present invention, the protein is in helical and / or crystalline form.

[0009] In one embodiment of the invention, during the process using the set of brine solutions of the invention, the physical state of the protein may change between helical and crystalline forms during subsequent food product processing steps, such as heat treatment steps and any post-heat treatment steps. Since either the helical or crystalline physical state of the protein has a positive effect on the coating properties of the food product, the actual state of the protein may change between these two states. However, it is particularly preferred that the physical state of the protein does not change after co-extrusion of the food product stream. In order to maintain the same product properties, such as surface smoothness, surface color, cooking properties of the obtained food product or the like, it is particularly advantageous to maintain the same physical state of the protein during co-extrusion of the food product stream and any further processing steps. Furthermore, particularly good results are obtained with the protein in crystalline form throughout the process using the set of brine solutions of the invention. By providing a coating that includes the protein in crystalline form, the coating of the food product provides a product that has the most optimal heat stability, i.e. that can be partially or completely cooked without having undesirable surface properties.

[0010] The protein of the present invention may be selected from the group consisting of edible proteins capable of forming a coating by gelling (aggregation and / or precipitation; whether in the presence of a coagulant) after coextrusion. Particularly preferred proteins include collagen.

[0011] The polymer included in the hybrid coating of the present invention may be selected from the group consisting of edible polymers that can combine with the proteins present in the hybrid coating to form a coating. Preferably, the polymer is selected from the group consisting of polysaccharides. Preferred polymers may include alginates and / or cellulose.

[0012] The co-extruded food product stream may contain strands of co-extruded food products that still need to be separated into separate individual food products (e.g. sausages), The food product stream may contain intermediate forms of strands where the individual food products are still linked together (head-to-butt linked) to form a string of linked food products.

[0013] The first brine solution of the present invention preferably comprises a salt selected from the group consisting of edible salts such as sodium chloride. Preferably, the first brine solution consists essentially of solubilized salt in an aqueous medium.

[0014] In some embodiments of the invention, the first brine solution comprises a saturated salt solution. Alternative first brine solutions may comprise at least 20% by weight salt, where weight percent is calculated based on the total weight of the brine solution. In preferred embodiments of the invention, the first brine solution may comprise at least 25% by weight salt, or preferably at least 30% by weight salt.

[0015] The second brine solution of the present invention preferably comprises a buffer salt selected from the group consisting of buffer salts having a pKa at 20° C. of at least 2.5. In certain preferred embodiments, the buffer salt may be selected from the group consisting of buffer salts having a pKa at 20° C. between 3.0 and 5.5. It has been found that by providing a second brine solution comprising a buffer salt having a pKa between 3.0 and 5.5, the pH of the brine solution may be maintained for a significantly longer period of time as compared to a brine solution that does not contain any buffer salt at all. Furthermore, the pH of the second brine solution may be maintained for an even longer period of time if the buffer salt is selected from the group consisting of buffer salts having a pKa at 20° C. between 3.5 and 5.0.

[0016] In an embodiment of the present invention, the second brine solution may contain a buffer salt selected from the group consisting of lactate, acetate, phosphate and carbonate. Preferred salts may contain sodium and / or potassium salts such as sodium lactate, potassium lactate, sodium acetate, potassium acetate, disodium phosphate, dipotassium phosphate, sodium carbonate and potassium carbonate. It is noted that the second brine solution of the present invention may contain a combination of two or more of the above salts.

[0017] In a further embodiment of the present invention, the amount of buffer salt contained in the second brine solution of the present invention is selected such that the second brine solution has a pH of at least 5.0. In particular, the second brine solution containing the buffer salt of the present invention may have a pH between 5.0 and 8.0. It has been found that by providing a second brine solution of at least 5.0, the physical state of the protein, e.g. collagen, can be controlled in a more reliable manner. Also, by providing a second brine solution with a pH of less than 8.0, the color of the final food product still complies with the predefined preferred color of the resulting final food product.

[0018] The amount of buffer salt may be selected such that the pH of the second brine solution of the present invention is within a predetermined range, however, it is also possible to provide a second brine solution that comprises a saturated salt solution. An alternative second brine solution may comprise at least 30% by weight of salt, where the weight percentage is calculated based on the total weight of the brine solution. In a preferred embodiment of the present invention, the second brine solution may comprise between 40% and 60% by weight of salt.

[0019] When a lactate salt, such as sodium lactate or potassium lactate, is used as the buffer salt, the second brine solution may contain between 50% and 80% lactate salt by weight. In a preferred embodiment, the second brine solution may contain about 60% lactate salt by weight.

[0020] When a carbonate, such as sodium carbonate or potassium carbonate, is used as the buffer salt, the second brine solution may contain between 50% and 70% carbonate by weight. In a preferred embodiment, the second brine solution may contain about 60% carbonate by weight.

[0021] When a phosphate, such as disodium phosphate or dipotassium phosphate, is used as the buffer salt, the second brine solution may contain between 30% and 50% phosphate by weight. In particular, the second brine solution may contain about 40% phosphate by weight.

[0022] In a further embodiment of the invention, the second brine solution may include a non-buffer salt, such as sodium chloride. It is noted that while a second brine solution containing only buffer salts is preferred, a combination, i.e., a second brine solution containing both buffer and non-buffer salts, provides good results in controlling and maintaining the pH of the second brine solution over an extended period of time.

[0023] In another aspect, the present invention relates to a method for the in-line processing of food products comprising the step of co-extruding a food dough into a stream of co-extruded food products having a proteinaceous coating or a hybrid protein-polymer coating, said method subsequently comprising the successive steps of:

[0024] a) subjecting the co-extruded food product stream to a food product fortification process, said food product fortification process comprising subjecting the food product stream to a set of brine solutions; and b) heat treating the food product stream obtained in step a), wherein in step a) the set of brine solutions comprises the set of brine solutions of the present invention.

[0025] It has been found that by providing a consolidation step in which the moisture content of the coating and the pH of the coating are controlled and maintained by using a set of brine solutions of the present invention, the consolidation step can then be advantageously combined with a heat treatment step.

[0026] In a preferred embodiment of the present invention, the heat treatment step of step b) may comprise a step in which the food product stream is subjected to two or more heat treatment steps. Such a single multiphase process step may comprise subjecting the food product stream to at least two heat treatment steps. However, further heat treatment steps may also be applied to the food product stream. For example, in a further preferred embodiment, the food product stream may be subsequently subjected to a third heat treatment step, i.e. after subjecting the food product stream to a first and a second heat treatment step. Furthermore, four or more subsequent heat treatment steps may also be applied. Typically, a single multiphase process step may be configured to contain about six heat treatment steps. It is noted that the configuration of the heat treatment steps of step b) depends on the specific food product to be produced and the production line design to which the method is applied. For example, for one product, the heat treatment process may include four heat treatment steps, such as drying, heating, partially cooking and (fully) cooking, while for another product, the heat treatment process may include three heat treatment steps, where the product leaving the single multi-phase process step is only partially cooked.

[0027] The thermal treatment step of step b) may be selected from the group consisting of drying, heating, partially cooking, cooking, and cooling the food product stream.

[0028] As used herein, the term "drying" refers to a process step in which excess water or moisture is removed from the surface of a food product stream to prevent coagulation of the food product coating and / or cooking.

[0029] The term "heating" as used herein refers to the process step in which the coating solidifies even though the food dough is not cooked.

[0030] The term "cooking in portions" as used herein refers to a process step in which the food dough is only partially cooked, i.e., resulting in a food product that is not yet readily edible, and which still needs to be further cooked, for example in a further subsequent multi-phase processing step, or by the end consumer while preparing the food product for eating.

[0031] The term "cooking" as used herein refers to the process step in which a food dough is cooked resulting in an edible food product. An alternative term for a food product that has been subjected to a cooking step is a "fully cooked" food product.

[0032] The term "cooling" as used herein refers to a process step in which the temperature of a food product is reduced using a cooling medium such as tap water or cold air, typically having a temperature of about 10°C to 15°C.

[0033] The term "chilling" as used herein refers to a process step in which food products are subjected to a chilling medium, which is a medium (e.g., water) that is intentionally made colder.

[0034] As already mentioned, different combinations of two or more heat treatment steps can be used in the method of the invention depending on the specific characteristics of the food product to be obtained, the starting materials used to produce the food product, the design of the production line to which the method is applied, and other parameters. An example of such a combination may relate to a method, in which a first heat treatment step comprises b.1) drying the food product stream and / or a second heat treatment step comprises b.2) at least partially cooking the food product stream. Another example of such a combination may relate to a method, in which a first heat treatment step comprises bi) drying the food product stream, a second heat treatment step comprises b.ii) heating the food product stream, and / or a third heat treatment step comprises b.iii) at least partially cooking the food product stream.

[0035] It is noted that with regard to the process conditions of the heat treatment step of the present invention, the temperature may range from 50° C. to 150° C., the relative humidity may range from 0% to 100%, and the air velocity may range from 1 m / s to 10 m / s.

[0036] In a preferred embodiment, the heat treatment step comprises drying the food product stream at a temperature between 50° C. and 80° C., preferably between 60° C. and 75° C. The relative humidity during drying of the food product stream may be up to 10%, preferably up to 5%.

[0037] With regard to heating the food product stream, the heat treatment step may include a temperature between 60° C. and 90° C., preferably between 70° C. and 80° C. The relative humidity during heating the food product stream may be between 15% and 40%, more preferably between 25% and 35%.

[0038] Partially cooking the food product stream may involve a temperature between 70° C. and 100° C., more preferably between 80° C. and 90° C. The relative humidity during partially cooking the food product stream may be between 30% and 60%, preferably between 40% and 50%.

[0039] In a further embodiment, the heat treatment step comprises cooking the food product stream at a temperature between 70° C. and 100° C., preferably between 80° C. and 90° C. The relative humidity of the food product stream during cooking may be between 60% and 80%, more preferably between 65% and 75%.

[0040] The method of the present invention may further comprise the step of separating the strands of co-extruded food product into individual food products. As already mentioned above, the food product stream may comprise strands of co-extruded food product, the method of the present invention further comprising the steps of:

[0041] Separating the strands of co-extruded food products into individual food products before subjecting the stream of food products to step a).

[0042] Alternatively, the coextruded food product strands may be divided into individual food products after subjecting the food product stream to step a) and preferably before subjecting the food product stream to step b). However, compared to the consolidation step which involves separation of the coextruded food product strands into individual food products (typically totaling about 30 to 60 seconds), in a preferred embodiment the method of the invention comprises an initial hardening step having a significantly shorter duration (as little as 0.1 to 0.5 seconds) immediately after or even during coextrusion of the coextruded food product strands. It is noted that the initial hardening step provides a first initial strength to the coating of the coextruded food product strands and promotes separation of the coextruded food product strands into individual food products. It is further noted that the initial hardening step may be performed by subjecting the coextruded food product strands to a brine solution, for example a first brine solution, a second brine solution, or even a further brine solution. Thus, in a preferred embodiment, the method of the present invention comprises the following steps:

[0043] subjecting the strands of co-extruded food product to an initial hardening step prior to separating the strands of co-extruded food product into individual food products, said initial hardening step comprising subjecting the strands of co-extruded food product to a brine solution selected from the group consisting of a first brine solution, a second brine solution, a further brine solution, and combinations thereof. In one embodiment, the brine solution used for the initial hardening step is preferably the first brine solution.

[0044] Due to the short duration of the initial hardening step, maintaining the pH of the brine solution used in the initial hardening step is not as critical, therefore a brine solution containing only sodium chloride, such as the first brine solution, could be sufficient for such a step without risking causing changes in the physical state of the protein.

[0045] In an embodiment of the present invention, the duration of use of both brine solutions included in the set of brine solutions of the present invention is different. In a preferred embodiment, the duration of use of the first brine solution is shorter compared to the duration of use of the second brine solution. In an embodiment of the present invention, the duration of use of the first brine solution is significantly shorter compared to the duration of use of the second brine solution. As used herein, the term "significantly" may refer to a difference having a factor of 10 to about 20. Preferably, the duration of use of the first brine solution is about 1 second to about 5 seconds, and the duration of use of the second brine solution is about 30 seconds to about 60 seconds.

[0046] Furthermore, the method of the present invention may comprise the steps of:

[0047] applying liquid smoke to the stream of food products prior to subjecting said stream of food products to step b).

[0048] In a further aspect of the invention, the invention relates to a brine solution comprising a salt of lactic acid. It has been found that by providing a brine solution, such as the second brine solution of the invention, comprising a salt of lactic acid, not only is the aesthetic quality of the final product improved, but the taste of the final product is also significantly improved.

[0049] The salt of lactic acid may be a potassium salt of lactic acid or a sodium salt of lactic acid. The lactate salt of the brine solution of the present invention may be an L-lactate salt. In a further preferred embodiment, the lactate salt is produced by fermentation from sugar. An example of such a suitable and preferred lactate salt is PURASAL. (R) It is commercially available under the trade name HiPure P Plus (Corbion Inc.) The brine solution of the present invention may consist essentially of lactate salts solubilized in an aqueous medium.

[0050] In one embodiment of the invention, the brine solution comprises a saturated lactate solution. Alternative brine solutions may comprise at least 30% by weight lactate, the weight percentage being calculated based on the total weight of the brine solution. In a preferred embodiment of the invention, the brine solution may comprise between 40% and 60% by weight lactate.

[0051] The present invention further relates to a system for in-line processing of food products using the method of the present invention.

[0052] The invention further relates to the use of the set of brine solutions of the invention in a method for in-line processing of food products. In particular, the invention relates to the use of the set of brine solutions in an enrichment step in a method for in-line processing of food products.

Claims

1. 1. A set of brine solutions for use in a method for in-line processing of a food product, comprising a first brine solution and a second brine solution, the set comprising: The method comprises: co-extruding the food dough into a co-extruded food product stream having a protein-containing coating or a hybrid protein-polymer coating; subjecting said co-extruded food product stream to a food product fortification process. Including, The food product fortification process comprises: i) a coating moisture content reduction step using a first brine solution, said first brine solution comprising a salt solubilized in an aqueous medium; and thereafter ii) a coating pH fixing step using the second brine solution, the second brine solution comprising a buffer salt solubilized in an aqueous medium; A set of brine solutions comprising the steps of:

2. 2. The set of brine solutions according to claim 1, characterized in that the buffer salts are selected from the group consisting of buffer salts having a pKa at 20° C. of at least 2.5, preferably between 3.0 and 5.5 or between 3.5 and 5.

0.

3. 3. The set of brine solutions according to claim 1 or 2, characterized in that the buffer salts are selected from the group consisting of lactate, acetate, phosphate and carbonate.

4. 10. The set of brine solutions according to any one of the preceding claims, characterized in that the buffer salts are selected from the group consisting of sodium lactate, potassium lactate, sodium acetate, potassium acetate, disodium phosphate, dipotassium phosphate, sodium carbonate and potassium carbonate.

5. 10. The set of brine solutions according to any one of the preceding claims, characterized in that the amount of buffer salts is selected to result in a brine solution having a pH of at least 5.0, preferably between 5.0 and 8.

0.

6. 10. The set of brine solutions according to any one of the preceding claims, characterized in that the salt of the first brine solution is selected from the group consisting of edible salts.

7. 10. The set of brine solutions according to any one of the preceding claims, characterized in that the first brine solution and / or the second brine solution comprises a saturated salt solution.

8. 7. The set of brine solutions according to any one of claims 1 to 6, characterized in that the second brine solution comprises at least 30% by weight of salt, preferably between 40% and 60% by weight of salt.

9. 6. The set of brine solutions according to any one of claims 1 to 5, characterized in that the second brine solution comprises between about 50% and 80% by weight, preferably 60% by weight, of a lactate salt such as sodium or potassium lactate or a carbonate salt such as sodium or potassium carbonate.

10. 6. The set of brine solutions according to any one of claims 1 to 5, characterized in that the second brine solution comprises between 30% and 50% by weight of a phosphate such as disodium phosphate or dipotassium phosphate, preferably about 40% by weight.

11. 10. The set of brine solutions according to any one of the preceding claims, characterized in that the second brine solution further comprises a salt which is not a buffer salt, such as sodium chloride.

12. 1. A method for in-line processing of a food product comprising the steps of co-extruding a food dough into a stream of co-extruded food products having a protein-containing coating or a hybrid protein-polymer coating, comprising: wherein the method then comprises the following successive steps: a) subjecting the co-extruded food product stream to a food product fortification process, said food product fortification process comprising subjecting the food product stream to a set of brine solutions; and b) heat treating the food product stream obtained in step a); Including, 12. A method for in-line processing of food products, characterized in that in step a) the set of brine solutions comprises a set of brine solutions according to any of claims 1 to 11.

13. 13. The method according to claim 12, characterized in that in step b) the food product stream is subjected to two or more heat treatment steps.

14. 14. The method of claim 13, wherein the two or more thermal treatment steps are selected from the group consisting of drying, heating, partially cooking, cooking, and cooling the food product stream.

15. The food product stream comprises strands of co-extruded food products, the method comprising the steps of: - dividing said co-extruded food product strands into individual food products before subjecting the stream of food products to step a), 15. The method according to any one of claims 12 to 14, further comprising:

16. The method comprises the steps of: - subjecting the strands of co-extruded food product to an initial hardening step prior to separating the strands of co-extruded food product into individual food products; Further comprising:

16. The method of claim 15, wherein the initial hardening step comprises applying to the strands of co-extruded food product a brine solution selected from the group consisting of a first brine solution, a second brine solution, an additional brine solution, and combinations thereof.

17. The method comprises the steps of: - applying liquid smoke to the stream of food products before subjecting said stream of food products to step b); 17. The method according to any one of claims 12 to 16, further comprising:

18. A brine solution containing a salt of lactic acid.

19. 19. The brine solution of claim 18, wherein the salt of lactic acid is selected from the group consisting of potassium lactate, potassium L-lactate, sodium lactate, and sodium L-lactate.

20. 20. The brine solution of claim 18 or 19, wherein the brine solution comprises a saturated lactate solution.

21. A system for in-line processing of food products using a method according to any one of claims 12 to 17.

22. 12. Use of the set of brine solutions according to any one of claims 1 to 11 in a method for in-line processing of food products.