Food Heat Treatment Method

Abstract

The present invention provides a method for heat-treating a food product having a protein-containing casing or a hybrid casing comprising a protein and a polymer in a heat treatment device, the method comprising: providing the food product; exposing the food product to a salt solution; transporting the food product to the heat treatment device; and subjecting the food product to a heat treatment step, the heat treatment step comprising at least a) drying the food product and b) subsequently further heat-treating the food product. The method further comprises determining a denaturation temperature of the protein and setting climatic parameters of the heat treatment device such that the dew point of the air in the device is equal to or less than the determined denaturation temperature, and step a) ends when the surface temperature of the casing is equal to the dew point of the air in the device.

Description

[Technical field]

[0001] The present invention relates to a method for the thermal treatment of a food product in a thermal processing device, in particular to a method for the thermal treatment of a food product having a casing comprising a protein or a hybrid casing comprising a protein and a polymer in a thermal processing device. [Background technology]

[0002] Food products with an enveloping layer comprising a protein such as collagen are generally known and are described, inter alia, in US Pat. No. 5,399,363. This document describes the co-extrusion of a food product with a co-extruded strand of food dough and an enveloping encapsulating said food dough into a co-extruded food stream. Following extrusion, the enveloping strand is usually led to a coagulation bath for strengthening purposes. Under the influence of the coagulation solution, the protein coagulates and / or precipitates, strengthening the enveloping layer of the co-extruded food stream. In this way, a strand of food dough is formed that is at least partially enveloping with a strong enveloping layer of a protein such as collagen.

[0003] A disadvantage of the known methods is that the properties of the casing material and thus the processability of the food product, e.g. a co-extruded food product stream comprising a stream of individual sausages, a stream of food product strands or a stream of sausages connected to one another (head-tail connection), may change during the processing of the food product. It is difficult to predict the changes in the properties of the casing material. Furthermore, the changes in the properties of the casing material are irreversible. Therefore, once the properties of the casing material have changed, it is not possible to process the food product to obtain a final food product, e.g. a sausage with an acceptable quality.

[0004] A particular drawback of known methods using proteins or proteins with viscous gelling agents as encapsulating materials for the co-extrusion of elongated food products is the uncontrolled properties (particularly the surface state) of the final food product. It has been observed that by changing the process settings after the co-extrusion of the food dough strands and the encapsulating material, the properties of the protein encapsulating material can be irreversibly altered. This can include changes in the surface properties of the encapsulating material with respect to the smoothness of the surface of the food product, e.g. changes in the "see and feel" of the food product. Changing the process settings after co-extrusion in subsequent processing steps, such as brining, separating, crimping, smoking, drying, packaging, cooking and / or chilling the food product, can result in uncontrolled changes in the resulting food product, such as undesirable surface states, e.g. sticky, inconsistent and / or dirty surfaces, as opposed to the normally desired smooth, presentable and stable surface. Such uncontrolled and irreversible changes in surface properties can reduce the processability of the food product, and may even result in the food product (or even the entire food product stream) having to be discarded. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Dutch Patent 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 food products having protein-containing or hybrid protein-polymer encasements.

[0007] Furthermore, despite the need for greater control over the production of foods having proteinaceous or hybrid protein-polymer encapsulations, it is desirable to produce foods that closely resemble the natural "chew" of natural encapsulations, such as lamb encapsulations.

[0008] Furthermore, there is a need to reduce the thermal processing time of foods, particularly the drying time required to dry foods having a protein-containing or hybrid protein-polymer encasement, without adversely affecting the properties of the food during its manufacture / processing, and the properties of the final food product, i.e., after the food production process is completed. [Means for solving the problem]

[0009] In order to meet one or more of the above identified needs and demands, the present invention provides a method for thermally treating a food product having a protein-containing encasement or a hybrid protein and polymer-containing encasement in a thermal processing device, said method comprising: providing said food product; - exposing the food to a brine solution; - conveying said food product to a heat treatment device; - subjecting said food product to a heat treatment step. The heat treatment step of the present invention may comprise multiple separate heat treatment steps, but for the method of the present invention, the heat treatment step comprises at least a) drying the food product; b) subsequently further heat treating the food product. The method of the present invention further comprises - determining the denaturation temperature of a protein contained in the envelope of the food product prior to conveying the food product to the thermal processing device; - adjusting the temperature of the heat treatment device so that the dew point of the air in the heat treatment device is equal to or lower than the determined denaturation temperature of the protein contained in the packaging of the food product. atmosphere and setting the parameters of [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a flow chart illustrating the general method of the present invention. [Diagram 2]FIG. 2 is a graph showing the denaturation temperature using potassium lactate in the extended salting step. [Figure 3A] FIG. 3A is a graph showing the denaturation temperature using magnesium sulfate in an extended salting step. [Figure 3B] FIG. 3B is a graph showing the denaturation temperature using sodium chloride in an extended salting step. [Figure 3C] FIG. 3C is a graph showing denaturation temperatures using dipotassium phosphate in an extended salting step. [Figure 4A] FIG. 4A is a graph of the first test showing the relationship between temperature and time in the heat treatment. [Figure 4B] FIG. 4B provides a table of the data and parameters used in the graph of FIG. 4A. [Figure 4C] FIG. 4C is an exemplary diagram of the food products obtained from the data and parameters used in the first test. [Figure 5A] FIG. 5A is a graph of the second test showing the relationship between temperature and time in the heat treatment. [Figure 5B] FIG. 5B provides a table of the data and parameters used in the graph of FIG. 5A. [Figure 5C] FIG. 5C is an exemplary diagram of the foods derived from the data and parameters used in the second test. [Figure 6A] FIG. 6A is a graph of the third test showing the relationship between temperature and time in the heat treatment. [Figure 6B] FIG. 6B provides a table of the data and parameters used in the graph of FIG. 6A. [Figure 6C] FIG. 6C is an exemplary diagram of the foods derived from the data and parameters used in the third test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The drying of the food product and the subsequent further heat treatment of the food product are consecutive steps, and the step of drying the food product is terminated when the surface temperature of the packaging is equal to the dew point of the air in the heat treatment device, determined before, and preferably immediately before, entering the heat treatment device, so that at least during the drying step of the food product the end of the drying step can be more clearly and more precisely defined based on its surface temperature and the dew point based on the denaturation temperature of the proteins contained in the packaging of the food product. atmosphere It has been found that when the above parameters are selected, the above identified needs and desires are met.

[0012] The heat treatment equipment is designed to ensure that the dew point of the air in the heat treatment equipment is below the determined denaturation temperature of the protein contained in the food packaging. atmosphere Select the parameters and check if the food surface temperature is atmosphere It has been found that by carrying out a significant temperature change, i.e. increasing the temperature of the heat treatment device, by the time the temperature of the heat treatment device is equal to the dew point temperature of the casing, the physical state of the protein contained in the casing can be controlled in a sustainable, reliable and stable manner so that the smoothness of the surface of the casing can be controlled during the production of the food product. In particular, it has been found that by controlling the moment at which the drying stage of the heat treatment is terminated before entering more severe heat treatment conditions during further heat treatment of the entire food product, the total time for drying the food product, and therefore the total time for heat treating the food product itself, can be significantly reduced compared to the conventional drying methods described in the art. Furthermore, it has been found that the total time for heat treating the food product itself can be significantly reduced by using the method of the present invention compared to the conventional drying methods described in the art, while the natural "chewiness" and product behavior of the final food product are more similar to the "chewiness", "look" and product behavior of foods containing natural casings, such as sheep casings.

[0013] Considering the method of the present invention, by providing a heat treatment step in which the surface temperature is equal to the dew point temperature (which dew point temperature is based on (i.e., below) the denaturation temperature of the proteins contained in the encapsulation) at the transition point from the drying stage to a further heat treatment stage (e.g., partially or fully heating the food product), the physical state of the proteins is controlled in a more sustainable and reliable manner, i.e., producing dried foods with attractive properties, e.g., a smooth, non-sticky, non-staining surface and excellent textural properties.

[0014] Regarding the physical state of protein, it should be noted that such physical state can include three types of physical states, namely, crystalline phase, helical phase, and randomly wound phase. It has been found that when helical or crystalline protein is transformed into a protein with randomly wound shape, irreversible changes in encapsulation properties are expected. The protein that constitutes the encapsulation of food containing helical or crystalline protein is characterized by a smooth and attractive appearance and / or stable surface, whereas the protein that constitutes the encapsulation of food containing protein with randomly wound shape shows a more sticky, inconsistent, and / or dirty surface. As a result, in one embodiment of the method of the present invention, the protein is in helical and / or crystalline form.

[0015] In one embodiment of the present invention, during the implementation of the method of the present invention, the physical state of the protein may change between helical and crystalline form during the heat treatment step, preferably at least during the drying phase of the heat treatment step. The actual state of the protein may change between the two states, since the helical or crystalline physical state of the protein has a positive effect on the encapsulation properties of the food product. However, it is particularly preferred that the physical state of the protein does not change after the formation (e.g., co-extrusion) of the food product. It is particularly advantageous to maintain the same physical state of the protein during the co-extrusion of the food product and any further processing steps, in order to maintain the same product properties of the obtained food product, such as surface smoothness, surface color, cooking properties, etc. Furthermore, particularly good results are obtained with crystalline protein throughout the method of the present invention. By providing an encapsulation containing crystalline protein, the encapsulation of the food product has optimal thermal stability. That is, a product is provided that can be processed without undesirable surface properties, such as, for example, "melting" of the encapsulation during the drying phase.

[0016] The physical state of the proteins contained in the encapsulation can be controlled using various parameters during the processing of the coextruded food, such as pH, temperature, type of salt used, and salt concentration of the salt solution (e.g., salt solution and / or liquid smoke). Considering the parameters for controlling the physical state of the proteins contained in the encapsulation, it is noted that the parameter temperature is mostly a predefined, difficult to control, and gradually variable parameter. Also, the type of salt and the salt concentration used in the salt solution during the processing of the coextruded food are mostly predefined parameters and can only be changed gradually during the course of the process. Significant changes in the type of salt or the salt concentration are mostly only possible during maintenance procedures, when the continuous production of the coextruded food is interrupted and the operator can set the parameters of the subsequent continuous procedures for processing the coextruded food.

[0017] It has been found that by controlling the pH during each step (or at least the critical steps) of the method of processing the co-extruded food product, the physical state of the proteins contained in the encapsulation can be controlled in a sustainable and comprehensive manner. Important steps can include the process steps where the food product is pre-fortified (brined for a short time), fortified (brined for a long time) and / or colored (liquid smoke applied to the encapsulation). Furthermore, another important step can include the extrusion of the encapsulation itself, i.e., controlling the pH of a viscous gelling agent, including a protein such as collagen, before, during or immediately after application to the string of food dough as the encapsulation to form the co-extruded food product of the present invention.

[0018] Furthermore, it has been found that by controlling the pH of the envelope throughout the process of producing the food product of the present invention, other parameters are less of a concern and can be varied within wider ranges. atmosphere The starting conditions of do not require significant further adjustment before starting the heat treatment step of the present invention, i.e., no costly atmosphere Control procedures, e.g., turning off heat treatment equipment before starting heat treatment of food atmosphere The present invention provides a method for preventing the need for reducing humidity in a heat treatment device. atmosphere Regardless of the humidity and temperature of the heat treatment equipment, the method of the present invention optimizes the heat treatment equipment to achieve a food product with optimal processability and stability. atmosphere It has been found that this provides a reliable and stable method for adjusting the parameters, for example by adjusting the air velocity. It is also possible to adjust the temperature of the heat treatment device due to external influences and / or during the concentration and drying of the food. atmosphere Due to the food affecting the heat treatment equipment atmosphere By (continuously) changing the conditions, the thermal processing equipment can be atmosphere The same food properties can be achieved without the need to control and maintain the conditions of heat treatment equipment. atmosphere can be obtained by (continuously) adjusting the parameters of

[0019] The operator has a dew point temperature below the determined denaturation temperature of the protein contained in the envelope. atmosphere of heat treatment equipment so that atmosphere Although there are several parameters for adjusting the composition, the skilled artisan can easily adjust the composition to provide a food product having a protein-containing or hybrid protein-polymer envelope with good product properties and continuous processability. atmosphere Based on conditions atmosphere In addition, the operator can calculate and adjust the parameters to ensure that the dew point temperature does not exceed the determined denaturation temperature of the protein. atmosphere It should be noted that it has been found that the parameters must be selected such that in situations where the dew point temperature exceeds the determined denaturation temperature of the protein contained in the envelope, the occurrence of gelation (also called "melting") of the protein within the envelope increases significantly, resulting in an uncontrolled, cost-ineffective and time-inefficient method of heat treatment.

[0020] The protein of the present invention may be selected from the group consisting of edible proteins that can form an envelope by gelation (coagulation and / or precipitation; with or without the presence of a coagulant) after coextrusion. Particularly preferred proteins include collagen. It is further noted that the term "protein" as used herein may refer to a single type of protein, but may also include different types of proteins. As a result, in the case of an envelope in which the protein contains multiple types of proteins, the denaturation temperature as used herein may refer to a denaturation temperature range, rather than the denaturation temperature point that would likely be measured if the envelope contained a single type of protein.

[0021] The polymer included in the hybrid encapsulation of the present invention may be selected from the group consisting of edible polymers that can be combined with the proteins present in the hybrid encapsulation to form an encapsulation. Preferably, the polymer is selected from the group consisting of polysaccharides. Preferred polymers may include alginate and / or cellulose.

[0022] As already indicated above, the heat treatment step of the method of the present invention may include a number of separate processing steps. In addition to the drying step identified above, the further heat treatment step may include one or more subsequent heat treatment steps. For example, the one or more subsequent heat treatment steps may be selected from the group consisting of heating, partial cooking, cooking, chilling, and cooling the food. The further heat treatment step may be performed in the same heat treatment device, which may also perform the drying step. However, considering that the temperature may vary significantly between different heat treatment steps, the further heat treatment step may be performed in a subsequent heat treatment device, or at least in a separate section of the same heat treatment device defined in the method of the present invention.

[0023] In a particularly preferred embodiment of the invention, the further heat treatment step may comprise cooking the food product. By providing the drying process of the invention and defining the end point of the drying process based on the denaturation temperature of the proteins contained in the food product envelope, it has been found that the transition from the drying phase to the cooking phase can be identified as a clear turning point, where the thermal conditions are severely changed, from the drying phase to the cooking phase with its severe heating characteristics, without affecting the product properties of the food product envelope.

[0024] As used herein, the term "heating" refers to a process step in which the food dough is not cooked but the casing is solidified.

[0025] As used herein, the term "partially cooking" refers to a process step in which a food product is only partially cooked, i.e., resulting in a food product that is not yet ready to eat and that requires further cooking, e.g., in additional multi-stage post-processing steps or by the end user during preparation of the food product for eating.

[0026] As used herein, the term "cooking" refers to the process step in which a food dough is cooked into an edible food. Another term for a food that has undergone a cooking step is a "fully cooked" food. Depending on the legislation, which varies from country to country, the term "fully cooked" is subject to different interpretations. In this respect, it is noted that a "fully cooked" food is one in which the temperature of the core of the food dough has reached a temperature defined by the legislator of the country in which the food is produced. For example, in the Netherlands a "fully cooked" food is defined by a temperature of the core of the food dough of at least 72°C.

[0027] As used herein, the term "chilling" 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, usually having a temperature of about 10°C to 15°C.

[0028] As used herein, the term "refrigerating" refers to a process step in which a food product is exposed to a refrigeration medium, which is an intentionally cooled medium (eg, water).

[0029] The method of the present invention comprises the steps of: - After the heat treatment step, the food product may further comprise a step of subjecting it to a post-heat treatment step.

[0030] Such post-heat treatment steps can be selected from the group consisting of refrigerating, surface treating, cooking and packing the food. Another post-heat treatment can include cooking the food, especially cooking the food after it has been packed. Such so-called "cook-in-pack" methods have proven to be particularly beneficial in combining food packing with full cooking. Post-heat treatment steps can include surface treatment of the food by exposing it to steam, i.e. antimicrobial treatment of the surfaces of the food stream.

[0031] Heat Treatment Equipment atmosphereThe parameters can be selected from a wide variety of possible relevant parameters suitable for applying a drying phase to the food product during the thermal treatment step of the present invention. However, the most suitable parameters to be selected include dry bulb temperature, wet bulb temperature, relative humidity, absolute humidity, and atmosphere The air velocity can be as high as

[0032] The denaturation temperature of the protein contained in the food encapsulation can be preferably determined by carrying out a differential scanning calorimetry (DSC) measurement. Furthermore, the physical state of the protein contained in the encapsulation can be monitored by measuring the isoelectric current of the encapsulation. Alternatively, the physical state of the protein contained in the encapsulation can be monitored by measuring the pH of the encapsulation using a suitable pH indicator. For example, a suitable pH indicator can be methyl red bromocresol green indicator.

[0033] atmosphere The parameters of the heat treatment equipment are set before the heat treatment step is performed. atmosphere It may be predetermined based on conditions. Additionally or alternatively, atmosphere The parameters of the heat treatment device are adjusted during the heat treatment step, preferably during the concentration of the food product. atmosphere It can be adjusted based on changing conditions. atmosphere can be adjusted based on the changing denaturation temperature of the proteins contained in the food product envelope during the course of the method, which may be caused by changing conditions of any pre-thermal processing steps in preparing the food product provided for thermal treatment.

[0034] Heat Treatment Equipment atmosphere The conditions are preferably: atmosphere by using one or more sensors suitable for measuring the relevant parameters of, i.e., dry bulb temperature, wet bulb temperature, relative humidity, absolute humidity and air velocity. Such dry bulb temperature sensor, wet bulb temperature sensor, humidity sensor and air velocity sensor can be used to (optionally automatically) adjust the parameters.

[0035] The food product provided by the method of the present invention may be a food product produced by co-extrusion of a food dough and an encasement material selected from an encasement having a protein-containing encasement or a hybrid protein and polymer encasement. In a preferred embodiment of the present invention, the step of providing the food product comprises: i) co-extruding a strand of food dough and an envelope encasing the strand of food dough into a co-extruded food stream; ii) subjecting said co-extruded food stream to a food fortification step, which comprises exposing the food stream to a salt solution.

[0036] Additionally, the step of providing the food product further comprises: - before subjecting the co-extruded food stream to step ii), it may comprise a step of separating the co-extruded food stream into individual food products, preferably separating the co-extruded food stream obtained in step i). Furthermore, the step of providing the food products may comprise: - after subjecting the co-extruded food stream to step ii), the method may comprise the step of applying liquid smoke to the co-extruded food stream.

[0037] In one embodiment of the invention, the step of determining the denaturation temperature of the proteins contained in the food encasement may be performed after subjecting the co-extruded food stream to step ii), preferably after the step of applying liquid smoke to the co-extruded food stream. EXAMPLES

[0038] The food products were prepared by the schematic process set forth in FIG. 1. In the schematic process provided in FIG. 1, meat 1 and collagen gel 4 were provided to meat stuffer 2 and collagen stuffer 3, respectively. The meat 1 and collagen gel 4 were then provided to extruder 5 by meat stuffer 2 and collagen stuffer 3 to extrude food strings of meat dough encased by a collagen encapsulation. Prior to providing the extruded food strings to crimper 7, the surface of the food strings was sprayed with salt (i.e., a brine containing a saturated sodium chloride solution) 6 to allow an initial hardening of the encapsulation prior to transforming the food strands into individual links by crimping. After the food strings are crimped onto the individual food products (sausages), the food products are subjected to a short salting step 8 (2 seconds using a saturated sodium chloride solution) and a long salting step 9 (30-60 seconds using a 52% potassium lactate solution) to raise the pH of the casing above pH 5 (above the isoelectric point of collagen) and below the second critical point in the behavior of collagen at pH about 7.5, thereby bringing the collagen structure of the casing to the desired physical state. The long salting step 9 is followed by a step 10 of applying liquid smoke to the food casing. Optionally, although not visualized in FIG. 1, the food products may be rinsed with water (briefly for 2 seconds) to remove excess salt water from the food casing before performing step 10. Alternatively or additionally, such a rinsing step may be performed after performing the liquid smoke step 10. The food products are then transported to a cart with a rotating basket for placement in the Alkar Batch house 12 in step 11. After carrying out the method of the present invention in step 12, the food product was cooled on trays in a refrigerator at 4° C. (step 13) and subsequently packed 14.

[0039] Step 12: Optimal atmosphere For the conditions applied, i.e. drying and optional cooking of the food, Differential Scanning Calorimetry (DSC) was used to measure the denaturation temperature of the collagen envelope of the food (after salting in step 9). An example of such a DSC measurement is shown in Figure 2. Considering the results provided in Figure 2, the dew point temperature of the air in the heat treatment equipment (i.e., step 12) was atmosphere ) was set at 47.9°C.

[0040] As discussed in the following three exemplary tests, heat treatment can alternatively be atmosphere It has been found that different results occur depending on the initial and stepwise increase in dew point temperature and the time the food is exposed to the dew point temperature in the time step, whereby atmosphere A step ensures that the dew point of the air in the heat treatment device is below the determined denaturation temperature of the proteins contained in the food packaging.

[0041] Considering the denaturation temperatures provided in Figure 2 (using potassium lactate as the long-term salting step 9), it was further found that using different salts in the salting step 9 results in different denaturation temperatures and therefore different dew point temperatures in order to provide an optimal thermal treatment step (i.e. drying) of the food. Examples of different denaturation temperatures are shown in Figure 3 and DSC diagrams are provided for different long-term salting steps 9 with the following salt solutions: - Magnesium sulfate (Figure 3A): 40.2℃ - Sodium chloride (Figure 3B): 42.1℃ - Dipotassium phosphate (Figure 3C): 41.5℃

[0042] It has been found that exposing food to a potassium lactate solution provides a more advantageous collagen preparation than the other salt solutions listed above, at least in part due to the collagen's higher denaturation temperature than the other exemplary salt bath solutions. Specifically, exposing collagen to a potassium lactate solution provides: atmosphere Begin drying the collagen capsule prior to step 12. The potassium lactate solution initiates the osmosis process that extracts water from the collagen capsule and preconditions the collagen capsule by controlling its pH level to the appropriate isoelectric point of the collagen capsule. atmosphereThe water is properly released during step 12. Such advantages may be due to the collagen encapsulation being better attached to the food during the drying process, which may reduce the risk of blistering of the collagen encapsulation during drying.

[0043] At least in part, as evidenced by Fig. atmosphere It was found that due to the higher denaturation temperature provided by exposing the collagen encapsulation to potassium lactate salt solution prior to processing, in combination with dew point, humidity, and time step, superior encapsulation could be achieved.

[0044] Test 1 FIG. 4A shows the dew point of air in a heat treatment device. atmosphere This shows the first test showing the relationship between the parameters of and the temperature of the food dough, which is more specifically defined based on the surface temperature of the food and the dew point temperature relative to the denaturation temperature of the proteins contained in the food envelope. The dry bulb temperature is adjusted slightly over time so that the food is fully cooked at the specified core temperature (74°C in this example). The air velocity is maintained constant during the entire cooking period. As the dew point temperature increases, the humidity of the heat treatment (X) increases, thereby increasing the humidity at the heat treatment.

[0045] The graph in Figure 4A shows the onset or denaturation temperature of the protein. Dry bulb temperature, atmosphere The purpose of setting the parameters of humidity and dew point temperature, as well as air velocity, is to ensure that the dew point of the air in the heat treatment equipment is at least equal to or below the determined denaturation temperature of the proteins contained in the food packaging. atmosphere The trick is to slowly increase the humidity and dew point temperature.

[0046] Once the initiation or denaturation temperature is reached, the cooking process of the food dough can proceed by maintaining and ensuring good adhesion of the collagen encapsulation to the food dough without blistering of the encapsulation as the temperature of the food dough increases to the appropriate cooked core temperature. Because the initiation or denaturation temperature has been reached in the collagen, the collagen encapsulation is dry enough to allow the food dough to be further cooked without exposing it to higher temperatures and damaging the encapsulation's adhesion and appearance. However, if the parameters are not met as defined above, there is a risk of the encapsulation being defective and not being able to withstand the more aggressive heat treatment of the food dough to cook to the proper specifications.

[0047] Therefore, especially in the initial stages when the parameters are below the starting temperature, it is essential to keep the dew point temperature and humidity low enough to allow the collagen to adhere to the food dough and to dry sufficiently to the starting temperature, and indeed the dew point of the air in the heat treatment device is below the determined denaturation temperature of the proteins contained in the food packaging.

[0048] Figure 4A shows the initial drying of a food product with 5 grams of water per kilogram of air (5g / kg). atmosphere This illustrates a scenario where food is exposed to humidity. The dew point temperature is fairly low at 3.9°C and both the humidity and dew point temperature are sustained for a relatively long period of time. In this scenario, the dew point temperature is maintained below the surface temperature of the food, however the humidity and dew point temperature must be maintained at a low point for a fairly sustained long period of time (i.e. 40 minutes) which is a time consuming and expensive process.

[0049] 4A and 4B depict the relationship of the food dough temperature to the dry bulb temperature and dew point temperature over three time steps, which are adjusted at each time step. By starting at a low dew point temperature and maintaining the dew point temperature below the surface temperature for an extended period of time, the first step, consisting of 40 minutes in this example, provides a dried food with attractive properties of the physical state of the proteins contained in the envelope. The first test has two subsequent steps in which the dry bulb temperature is adjusted slightly at each step, but the dew point temperature increases significantly in the second step and less so in the third step, and the second and third time increments are shorter than the duration of the first step. The first test requires approximately 68 minutes of processing time for the food to reach a fully cooked state, which includes a yield loss of 21.5%.

[0050] As can be seen in Fig. 4C where the food product is depicted, we unexpectedly found that the physical state of the protein can be controlled in a more sustainable and reliable manner according to the parameters of the first test, and the food product has the attractive properties mentioned above of fully cooked food dough. Specifically, the key parameter in the first test, maintaining the dew point temperature below the denaturation temperature of the protein contained in the encapsulation, enables the food product to have such attractive properties.

[0051] Test 2 FIG. 5A shows the dew point of air in a heat treatment device. atmosphere This shows a second test showing the relationship between the parameters and the temperature of the food dough, more specifically defined based on the surface temperature of the food product and the denaturation temperature of the proteins contained in the food product envelope, which is determined before, and preferably just before, entering the heat treatment device. As with the first test, the dry bulb temperature is adjusted to increase over time, usually so that the food product is fully cooked at or above the core temperature (74°C in this example). The air velocity is kept constant during the entire cooking time.

[0052] 5A and 5B illustrate the advantage of adjusting the dry bulb temperature more frequently than in the first test while maintaining the dew point temperature below the surface temperature of the food product. In this example, by having more frequent time steps and adjusting the dry bulb temperature accordingly in conjunction with the incremental increase in dew point temperature while maintaining the important relationship between dew point and surface temperature discussed in the first test above, the overall process time to reach a fully cooked state is advantageously reduced to 40 minutes compared to 68 minutes, reducing the yield loss to 18.2%.

[0053] It is observed in Figures 5A and 5B that the dew point temperature and humidity are increased in 5 minute steps or increments while remaining below a threshold below the onset or denaturation temperature. Of course, the method is not limited to 5 minute steps, but advantageously including frequent time steps in combination with increasing dew point temperature and humidity can shorten the process over the first test parameters. Although the time steps and corresponding adjustments to dew point temperature and humidity are made more frequently, such adjustments are below the thresholds specified above and are at least dry enough to promote evaporation of water in the collagen without compromising the onset temperature. atmosphere Once the start temperature is reached, more energy can be introduced to further cook the food dough to specifications.

[0054] As observed in Figure 5C where the food product is depicted, we unexpectedly found that in the food product with protein containing encapsulation or hybrid protein-polymer encapsulation, the physical state of the protein can be controlled more sustainably and reliably according to the parameters of the first test, while the overall cooking time and yield loss are reduced, and the food product has the attractive properties mentioned above of fully cooking the food dough, specifically by the key parameters of the second test of maintaining humidity and dew point temperature below the denaturation temperature of the protein contained in the encapsulation for more frequent time increments, while making the process faster and more economically feasible.

[0055] Test 3 6A-6C illustrate the risks that arise when the dew point temperature is increased above the food surface temperature. As shown, in the first four time steps of the 5 minute increments, the dew point temperature increases far above the food surface temperature, thereby overshooting a predetermined favorable and unexpected threshold of the food surface temperature.

[0056] The first step starts relatively dry, with a dew point temperature of 25°C and humidity of 20g / kg compared to a much higher dry bulb temperature of 77°C, but with a starting surface temperature of about 8°C for the food. This creates an environment where the dew point and humidity rise too quickly, and there is a risk that the envelope will not adhere to the food fabric. Over time, the food will quickly become more susceptible to the harsher conditions before it reaches the starting temperature and elevated surface temperature. atmosphere When exposed to the condition trajectory, the collagen can become too wet and cause the food dough to run. Thus, from Figure 6A, the dew point and humidity trajectories are too aggressive towards moisture, creating a collagen encapsulation that softens and becomes a sticky substance, which cannot dry. In the fourth step, the dew point temperature is maintained at 65°C for the remaining cooking time (about 23 minutes), but at this stage the collagen encapsulation is not sufficiently dry, resulting in poor product quality, as shown in Figure 6C.

[0057] As in the second test, a process time of 48 minutes is achieved until the food dough is fully cooked, but FIG. 6C illustrates the food product resulting in bulging of the casing. According to the important parameters of the present invention established in the first and second tests, the heat treatment atmosphere However, if the unique dew point vs. surface temperature relationship is not met throughout the cooking process, such blistering will render the food unusable, negating the benefits derived from the first and second tests.

[0058] Even though there was a large difference between the dew point temperature and the dry bulb temperature in the first step, the surface temperature of the food product was significantly lower, about 8° C. From this observation of the starting temperatures in the third test compared to the first and second tests, the advantageous method of the present invention illustrates the non-obvious step of always maintaining the dew point at a temperature lower than the surface temperature of the food product. Furthermore, even if the dew point temperature is held for a long period of time as in the fourth step, if the dew point exceeds the surface temperature of the food product, inferior, potentially defective food products may be obtained.

[0059] The present invention provides the following aspects. [1] A method for heat treating a food product having a protein-containing envelope or a hybrid envelope containing a protein and a polymer in a heat treatment device, comprising the steps of: The method further comprising: providing said food product; - exposing the food product to a salt solution; - conveying the food product to the heat treatment device; - subjecting said food product to a heat treatment step, The heat treatment step comprises at least a) drying the food product; b) subsequently subjecting the food product to further thermal processing, The method further comprises - determining the denaturation temperature of the protein contained in the packaging of the food product prior to conveying the food product to the thermal processing device; - setting the parameters of the atmosphere of the heat treatment device such that the dew point of the air in the heat treatment device is equal to or lower than the determined denaturation temperature of the protein contained in the packaging of the food product, The method, wherein step a) ends when the surface temperature of the envelope is equal to the dew point of the air in the heat treatment device.

[0060] [2] The method of [1], wherein the further heat treatment step b) comprises one or more subsequent heat treatment steps.

[0061] [3] The method of [2], wherein the one or more subsequent thermal treatment steps are selected from the group consisting of heating, partially cooking, cooking, refrigerating, and cooling the food product.

[0062] [4] Any of the methods of [1] to [3], wherein the further heat treatment step b) comprises partially cooking or fully cooking the food product.

[0063] [5] The method of any of [1] to [4], wherein the further heat treatment step b) is carried out in the same heat treatment device or in a subsequent heat treatment device.

[0064] [6] The method, -Any of the methods [1] to [5], further comprising subjecting the food to a post-heat treatment step after the heat treatment step, the post-heat treatment step being selected from the group consisting of refrigerating, surface treating, cooking and packing the food.

[0065] [7] The method of [6], wherein the post-heat treatment step of surface treating the food product comprises exposing the food product to steam.

[0066] [8] The method of [6] or [7], wherein the post-heat treatment step of cooking the food product comprises cooking the food product after packing the food product.

[0067] [9] Any of the methods [1] to [8] in which the atmospheric parameters include atmospheric dry bulb temperature, wet bulb temperature, relative humidity, absolute humidity, and air velocity.

[0068]

[10] Any of the methods [1] to [9], wherein the denaturation temperature of the protein contained in the outer packaging of the food is determined by performing a differential scanning calorimetry (DSC) measurement.

[0069]

[11] Any of the methods of [1] to

[10] , wherein atmospheric parameters are adjusted based on changing atmospheric conditions in the heat treatment equipment during the heat treatment step and / or based on changing denaturation temperatures of the proteins contained in the outer packaging of the food product.

[0070]

[12] The method of

[10] or

[11] , wherein the atmospheric conditions of the heat treatment device are measured using one or more sensors selected from the group consisting of a dry bulb temperature sensor, a wet bulb temperature sensor, a humidity sensor, and an air velocity sensor.

[0071]

[13] The step of providing the food product further comprises: i) co-extruding a strand of food dough and an envelope containing the strand of food dough into a co-extruded food stream; and ii) subjecting said co-extruded food stream to a food fortification step comprising exposing the food stream to a salt solution; Any of the methods [1] to

[12] , including the steps of:

[0072]

[14] The step of providing the food product further comprises: The method of

[13] , further comprising separating the co-extruded food stream into individual food products prior to subjecting the co-extruded food stream to step ii), preferably separating the co-extruded food stream obtained in step i).

[0073]

[15] The step of providing the food product further comprises: The method of

[13] or

[14] , further comprising applying liquid smoke to the co-extruded food stream after subjecting the co-extruded food stream to step ii).

[0074]

[16] Any of the methods

[13] to

[15] , wherein the step of determining the denaturation temperature of the protein contained in the food encasement is carried out after subjecting the co-extruded food stream to step ii), preferably after applying liquid smoke to the co-extruded food stream.

[0075]

[17] The method according to any one of [1] to

[16] , wherein the salt solution contains potassium lactate.

Claims

1. 1. A method for heat treating a food product having a protein-containing or hybrid protein-polymer-containing envelope in a heat treatment device, comprising the steps of: The method further comprising: - providing said food product; - exposing said food to a salt solution; - conveying said food product to said heat treatment device; - subjecting said food product to a heat treatment step, The heat treatment step comprises at least a) drying the food product; b) subsequently subjecting the food product to further thermal processing, The method further comprises - determining the denaturation temperature of the protein contained in the packaging of the food product before conveying the food product to the thermal processing device; - setting the parameters of the atmosphere in the heat treatment device such that the dew point of the air in the heat treatment device is below the determined denaturation temperature of the protein contained in the packaging of the food product, The method of claim 1, wherein step a) ends when the surface temperature of the envelope is equal to the dew point of the air in the heat treatment device.

2. The method of claim 1 , wherein the further heat treatment step b) comprises one or more subsequent heat treatment steps.

3. 3. The method of claim 2, wherein the one or more subsequent thermal processing steps are selected from the group consisting of heating, partially cooking, cooking, refrigerating, and cooling the food product.

4. The method according to any one of claims 1 to 3, wherein the further heat treatment step b) comprises partially cooking or fully cooking the food product.

5. The method according to any one of claims 1 to 4, wherein the further heat treatment step b) is carried out in the same heat treatment device or in a subsequent heat treatment device.

6. The method further comprising: The method according to any one of claims 1 to 5, further comprising, after said heat treatment step, subjecting said food product to a post-heat treatment step, said post-heat treatment step being selected from the group consisting of refrigerating, surface treating, cooking and packing said food product.

7. 7. The method of claim 6, wherein the post-heat treatment step of surface treating the food product comprises exposing the food product to steam.

8. 8. The method of claim 6 or 7, wherein the post-heat treatment step of cooking the food product comprises cooking the food product after packing it.

9. The method of claim 1, wherein the atmospheric parameters include atmospheric dry bulb temperature, wet bulb temperature, relative humidity, absolute humidity, and air velocity.

10. The method according to any one of claims 1 to 9, wherein the denaturation temperature of the protein contained in the food encasement is determined by performing a Differential Scanning Calorimetry (DSC) measurement.

11. A method according to any one of claims 1 to 10, wherein atmospheric parameters are adjusted based on changing atmospheric conditions in the heat treatment equipment during the heat treatment step and / or based on changing denaturation temperatures of the proteins contained in the outer packaging of the food product.

12. 12. The method of claim 11, wherein the atmospheric conditions of the thermal processing apparatus are measured using one or more sensors selected from the group consisting of a dry bulb temperature sensor, a wet bulb temperature sensor, a humidity sensor, and an air velocity sensor.

13. providing the food product, i) co-extruding a strand of food dough and an envelope containing said strand of food dough into a co-extruded food stream; and ii) subjecting said co-extruded food stream to a food fortification step comprising exposing the food stream to a salt solution; The method according to any one of claims 1 to 12, comprising the steps of:

14. providing the food product, 14. The method of claim 13, further comprising separating the co-extruded food stream into individual food products prior to subjecting the co-extruded food stream to step ii), preferably separating the co-extruded food stream obtained in step i).

15. providing the food product, 15. The method of claim 13 or 14, further comprising applying liquid smoke to the co-extruded food stream after subjecting the co-extruded food stream to step ii).

16. 16. The method according to any one of claims 13 to 15, wherein the step of determining the denaturation temperature of the protein contained in the food encasement is carried out after subjecting the co-extruded food stream to step ii), preferably after applying liquid smoke to the co-extruded food stream.

17. The method of any one of claims 1 to 16, wherein the salt solution comprises potassium lactate.

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