Preparation method of composite gel Xinjiang brown cow leather jelly with high gel property

Abstract

The invention relates to a preparation method of composite gel Xinjiang brown cow leather jelly with high gel characteristics, which comprises the following steps: adopting Xinjiang brown cow leather, performing enzymolysis and depilation by using neutral protease and xylanase, boiling, filtering, seasoning, adding low-acyl gellan gum, guar gum and calcium chloride according to a specific proportion, boiling, canning, sterilizing and sealing, thereby obtaining the composite gel Xinjiang brown cow leather jelly. And thus, the composite gel cowhide jelly is obtained. The texture performance of the prepared composite gel cow leather jelly is superior to that of traditional cow leather jelly, the hardness and chewiness are remarkably increased by 63.64% and 60.59% respectively, and the storage modulus in dynamic viscoelasticity is increased; the highest melting temperature and solidification temperature of the compound skin jelly are 53.63 DEG C and 36.60 DEG C, and the melting temperature is increased to 156.06 DEG C; and the freeze-thaw water loss rate is reduced by 51.31% compared with that of the traditional skin jelly. The digestibility of the composite gel kraft jelly protein is delayed, and the predicted shelf life is 114 days. According to the preparation method disclosed by the invention, the edible hydrophilic polysaccharide can be added into the traditional cow leather jelly to improve the gel strength and improve the gel quality.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, specifically relates to the field of collagen food processing, and especially relates to a preparation method of composite gel cowhide jelly. Background Art

[0002] my country is a major livestock-raising nation, with the beef cattle industry playing a crucial role. Both the share of beef consumption and per capita beef consumption have been steadily increasing, and the scale of beef cattle farming has also been expanding. Xinjiang, one of China's five major livestock bases, is a major beef producer. Brown cattle are Xinjiang's largest breed, known for their ability to produce both meat and milk and their resilience to the local environment. Recent breeding efforts have yielded promising results, with the herd reaching 1.03 million head. However, since 2023, declining beef prices and uneven quality of beef cattle products have constrained the industry's development. The intensive processing and utilization of beef by-products, resulting from the surge in beef production, has become a key focus for investors. Cowhide is a major by-product of beef cattle, accounting for 5.1% to 8.5% of the total weight of the cattle. Currently, only a portion of high-quality cowhide is used in leathermaking, and the country still relies heavily on imports. In 2023, the value of raw cowhide imports accounted for 88.4% of the total raw hide production. Most domestic breeding environments are still free-range, which often causes mechanical damage to raw hides. Such cow hides are sold cheaply or directly discarded, and there is a lack of high-value-added channels. The efforts in deep processing are insufficient, and there are too few high-end downstream products in the industry, which affects the upgrading and development of the industrial chain.

[0003] Removing fur from animal skins is a prerequisite for their use in light industry, particularly for food. In recent years, a large number of edible animal skin products, such as seasoned skins, skin jellies, yellow gelatin, and donkey-hide gelatin, have emerged on the market. The degree of fur removal directly impacts the edible quality of the finished product. Currently used hair removal methods include burning, rosin glycerol ester depilation, and enzymatic depilation. Open flame singeing is the most traditional depilation method and is simple to perform, but it can cause some damage to the skin and produce harmful substances such as polycyclic aromatic amines and heterocyclic aromatic amines. Scalding involves placing freshly slaughtered carcasses in hot water at 60-80°C. This denatures the collagen, the main component of the skin, causing the pores to expand, thereby removing the hair. Heating time and temperature are key factors in the scalding process. If the temperature is too high and the heating time is too long, the pores will shrink rapidly, making hair removal difficult. If the temperature is too low and the heating time is too short, the pores will not expand, making hair removal equally difficult. Heating at the appropriate temperature and time can relax pores and remove hair, making the overall process simple. However, hair roots can easily remain and cannot be completely eradicated. If a small amount of hair remains on the surface after perming, singeing is required. Rosin glycerol ester hair removal involves contacting molten rosin glycerol ester with the surface of the skin to be depilated. It then rapidly solidifies, bonding the molten rosin glycerol ester to the surface hair, allowing the hair to be removed along with the adhesive. This method has low raw material costs, but requires multiple repetitions to completely remove the hair and cannot be recycled. Enzymatic hair removal degrades glycoproteins and proteoglycans in the basement membrane, breaking down peptide bonds and softening the hair and epidermis. Due to its safety, environmental friendliness, and low energy consumption, it has been widely studied in recent years. The specific hydrolysis capabilities of proteases and glycosidases are used for pre-treatment of hides and skins to improve the quality of the removed hair.

[0004] The skin of cowhide contains a large amount of collagen. Boiling the skin, adding appropriate seasonings, and then condensing it into a jelly is a common way for people to eat it. The resulting jelly food is low in fat, calories, and protein, with a smooth texture, which meets the modern consumer's pursuit of a healthy diet. It is also inexpensive and simple to make, making it popular with consumers. Currently, the traditional skin jelly process involves adding water to the skin at a certain material-to-liquid ratio, boiling it, and then seasoning it. This jelly, which relies solely on the denaturation of collagen from the hide into gelatin, still has weak gelling properties, leading to water precipitation in warmer temperatures and even failure to form at room temperature, resulting in reduced gel strength. This not only significantly affects flavor and taste, but also significantly limits subsequent processing and transportation. Polysaccharide colloids have been widely studied to improve the properties of heat-induced protein gels. Adding synergistic ingredients to single gel products and further combining them with polymers in food can enrich and improve gelling behavior.

[0005] Gellan gum is a bacterial extracellular anionic linear heteropolysaccharide, which is divided into natural gellan gum and low acyl gellan gum after deacylation. The former forms elastic thermoreversible gel, while the latter forms low acyl gellan gum after deacylation.2+ Mg 2+ Under the action of divalent ions, acyl gellan gum forms a brittle, high-hardness, thermally irreversible gel. Highly acyl gellan gum exhibits superior water solubility and transparency, leading to its widespread application research. Guar gum is a nonionic, water-soluble heteropolysaccharide primarily composed of galactomannan, which has a fat-like texture and can be added to foods to improve taste. Low-acyl gellan gum forms a high-hardness gel in the presence of metal ions, but its internal stability and toughness are poor. Guar gum can form a high-viscosity gel at low concentrations. Combining these two gels can achieve optimal properties for jelly and improve the gel quality of cow jelly. Predicting the shelf life of foods can inform storage, marketing strategies, quality assurance during distribution, and optimization of production and processing technologies. Research on quality changes during storage at different temperatures and predicting shelf life provides a scientific basis for the preservation and processing of compound gel jelly.

[0006] Traditional leather jelly is formed by the thermal denaturation of collagen components and the dissolution of gelatin during the thermal processing of animal hides. However, the gelling properties of gelatin gels based primarily on gelatin alone are still relatively weak. The melting temperature of gelatin gels is typically below 35°C, which leads to water precipitation and gel structure destruction in seasons with higher temperatures, greatly restricting subsequent processing and transportation. The addition of two heterogeneous hydrophilic polysaccharide colloids, gellan gum and guar gum, can enrich the gelling properties of traditional cowhide jelly. Therefore, how to provide a Xinjiang brown cowhide jelly that uses a specific process to treat Xinjiang brown cowhide resources and combines a specific ratio of gellan gum and guar gum to produce a composite gel with high gelling properties? This not only achieves the "full utilization" of livestock resources, but also upgrades traditional food into a modern industrial product through technological innovation. Its significance lies not only in the creation of economic value, but also in providing a replicable model for the sustainable development of animal husbandry - transforming by-products into resources and turning "scraps" into "gold ingots." Summary of the Invention

[0007] Aiming at the problem that the existing technology of using gelatin as the main gelling agent to prepare jelly has insufficient gel network stability and poor thermal stability, which leads to limited processing and application, the technical problem to be solved by the present invention is to provide a preparation method of Xinjiang brown cowhide jelly, a composite gel with high gel strength, good thermal stability and good water retention. The hair removal is carried out by enzymatic method, and the gel behavior is enriched and improved by adding edible gel polysaccharides and further combining with polymers in food. The obtained composite gel Xinjiang brown cowhide jelly improves the traditional cowhide jelly caused by colloid melting due to high temperature or even room temperature, thereby resulting in reduced sensory quality, low gel strength, easy water precipitation and other problems. It has an impact on the utilization and development of Xinjiang brown cattle by-product resources and sustainable development.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The invention provides a composite gel Xinjiang brown cowhide jelly. The composite gel Xinjiang brown cowhide jelly is obtained from Xinjiang brown cowhide, neutral protease, xylanase, drinking water, salt, low acyl gellan gum, guar gum, calcium chloride and sodium bicarbonate.

[0010] The present invention provides a method for preparing a composite gel cowhide jelly, comprising the following steps:

[0011] a. Prepare the necessary Xinjiang brown cattle hides, drinking water, salt, low acyl gellan gum, guar gum, calcium chloride, sodium bicarbonate, neutral protease, and xylanase;

[0012] b. Frozen cowhide was taken out and thawed at room temperature, washed to remove excess subcutaneous fascia, and placed in a 5% NaHCO3 solution at a ratio of 1:3 (w:v) for 16 hours. After repeated rinsing, neutral protease and xylanase were used for enzymatic dehairing. The material-liquid ratio was set to , and a composite enzyme solution of neutral protease and xylanase was added. The enzymatic hydrolysis temperature was 50 ° C and the enzymatic hydrolysis time was 4 hours to obtain a dehairing rate of 99.962% dehaired cowhide.

[0013] c. The treated cowhide and drinking water were added to a sandwich pot in a mass ratio of 1:3 and cooked at 95 ° C for 2.5h to dissolve the collagen in the cowhide. The insoluble matter was filtered to remove the insoluble matter, and 1% salt was added to the weight of the whole glue for seasoning. Then, 0.5% low acyl gellan gum and 0.5% guar gum powder and 0.06% calcium chloride were added. The mixture was boiled at 90 ° C for 20min until dissolved to obtain cowhide glue.

[0014] d. The boiled glue is canned using a filling machine;

[0015] e. Place the canned semi-finished product in a 95°C water bath for sterilization for 30 minutes and then seal;

[0016] f. The sterilized product was cooled to room temperature and refrigerated at 0-4°C for 12 hours to obtain a composite gel cowhide jelly with a hardness of 833.403±48.132g and an elasticity of 0.965±0.008.

[0017] Preferably, in step b, the material-liquid ratio is 1:6 (w:v).

[0018] Preferably, the enzyme solution concentration in step b is 800 U / mL, the ratio of neutral protease to xylanase activity is 3:7, and the pH is 7.

[0019] Preferably, the enzymatic hydrolysis temperature in step b is 50° C. and the enzymatic hydrolysis is carried out for 4 hours.

[0020] Preferably, in step c, 1% salt based on the weight of the entire glue solution is added for seasoning.

[0021] Preferably, 0.5% low acyl gellan gum is added in step c.

[0022] Preferably, 0.5% guar gum powder is added in step c.

[0023] Preferably, 0.06% calcium chloride is added in step c.

[0024] Furthermore, the present application provides the application of the preparation method of the above-mentioned composite gel Xinjiang brown cowhide jelly in the preparation of composite gel Xinjiang brown cowhide jelly.

[0025] Through the above technical solutions, this application achieves the following beneficial effects:

[0026] According to the preparation method of the composite gel Xinjiang brown cowhide jelly provided by the present invention, a hydrophilic edible polysaccharide colloid commonly used on the market is added to the traditional jelly for boiling, and the jelly formed by cooling has strong thermal stability, good water retention, and good sensory quality and texture characteristics. It improves the problems of colloid melting caused by high temperature or even room temperature in traditional cowhide jelly, which leads to a decrease in sensory quality, low gel strength, and easy water precipitation. The prepared composite gel Xinjiang brown cowhide jelly has strong final stability, a smooth product, and a good taste. The product is fully formed, has strong resistance to freeze-thaw water loss, and good thermal stability. It not only realizes the "full utilization" of livestock resources, but also upgrades traditional food to modern industrial products through technological innovation. Its significance lies not only in the creation of economic value, but also in providing a replicable model for the sustainable development of animal husbandry, converting by-products into resources, and turning "scraps" into "gold ingots."

[0027] This patent is the first to prepare a composite gel jelly by modifying it with two exogenous polysaccharide colloids, guar gum and low-acyl gellan gum, to improve the quality of the gel. The texture properties, thermal stability, and moisture retention capacity are all superior to those of traditional cowhide jelly. The digestion properties are delayed, and the shelf life is 114 days at 4°C, solving the problem of poor gel properties of traditional cowhide jelly. Compared with the patent 202311367662.8, a rapid preparation method for pig skin jelly, the hardness and chewiness are improved. In theory, it breaks through the limitation of traditional jelly relying on a single collagen protein. In practice, it is convenient and feasible. The innovation lies in the first addition of guar gum and low-acyl gellan gum to construct a composite gel system to prepare jelly with high gel properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Shown is a graph of gel strength of cowhide jelly obtained from different dehairing treatments.

[0029] Figure 2 Shown are graphs showing the variation of complex viscosity, G', and G" with angular velocity.

[0030] Figure A shows the variation of complex viscosity at different values; Figure B shows the variation of G'; and Figure C shows the variation of G" with angular velocity.

[0031] Figure 3 Shown is the result graph of water holding rate of different cowhide jellies.

[0032] Figure 4 Shown is the result of different cowhide frozen gel strength

[0033] Figure 5 Shown are the TG, DTG, and DSC change diagrams of different cowhide jellies.

[0034] Figure A shows the changes in TG of different cow skin jellies; Figure B shows the changes in DTG of different cow skin jellies; Figure C shows the changes in DSC of different cow skin jellies.

[0035] Figure 6 Shown is a graph showing the changes in melting and solidification temperatures of different cowhide jellies.

[0036] Figure 7 Shown is the freeze-thaw water loss rate change diagram of different cowhide jellies.

[0037] Figure 8 Shown are SEM images (1000×) of different glue addition groups.

[0038] Figure A shows the result diagram of the technical solution in Example 4; Figure B shows the result diagram of the technical solution in Example 5; Figure C shows the result diagram of the technical solution in Example 6; and Figure D shows the result diagram of the technical solution in Example 7.

[0039] Figure 9 Shown is the digestibility results of different cowhide jellies.

[0040] Figure 10 Shown is the change of TVB-N and sensory score of compound gel jelly during storage.

[0041] Figure A shows the changes in TVB-N; Figure B shows the changes in sensory scores.

[0042] Figure 11 Shown are actual pictures of different glue addition groups.

[0043] Figure A shows a physical diagram of the technical solution in Example 4; Figure B shows a physical diagram of the technical solution in Example 5; Figure C shows a physical diagram of the technical solution in Example 6; and Figure D shows a physical diagram of the technical solution in Example 7. DETAILED DESCRIPTION

[0044] The following examples are used to further illustrate the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, modifications or replacements made to the inventive method, steps or conditions are within the scope of the present invention. The Xinjiang brown cattle hide, drinking water, salt, low acyl gellan gum, guar gum, calcium chloride, sodium bicarbonate, neutral protease, and xylanase used in this application are all commercially available products, and the general public can purchase them through supermarkets, biological companies, etc.

[0045] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods. Unless otherwise specified, the materials, reagents, etc. used in the following examples are all commercially available.

[0046] Example 1: Processing of cowhide

[0047] The frozen Xinjiang brown cattle hide was taken out and thawed at room temperature, washed to remove excess fascia under the skin, and placed in a 5% NaHCO3 solution at a ratio of 1:3 (w:v) to swell for 16 hours. The hide was taken out and rinsed repeatedly, and enzymatic dehairing was performed using neutral protease and xylanase. The material-liquid ratio was 1:6 (w:v), the enzyme solution concentration was 800U / mL, the enzyme activity ratio of neutral protease to xylanase was 3:7, the pH was 7, the enzymatic hydrolysis temperature was 50℃, and the enzymatic hydrolysis was performed for 4 hours to obtain enzymatically dehaired cattle hide.

[0048] Example 2: Dehairing of cowhide

[0049] The frozen cowhide was taken out and thawed at room temperature, washed to remove excess fascia under the skin, placed in 5% NaHCO3 solution at a ratio of 1:3 (w:v) to swell for 16 hours, taken out and rinsed repeatedly, and the cowhide was physically dehaired using a scraper.

[0050] Example 3: Comparison of the strength of frozen gels produced from cowhide using different hair removal methods

[0051] Boil the different treated cowhide with water at a ratio of 1:3 (w:v) in a water bath at 90℃ for 3h. Filter 15mL of the cowhide soup through gauze and pour it into a 25mL beaker. Place it at 4℃ for 24h to freeze. Take it out and equilibrate it at room temperature for 10min. Use a P / 5 probe, test the speed before, during and after at 1mm / s, puncture distance 4mm, and record the gel strength. Figure 1 As shown in the results, the gel strength of the jelly made from the cowhide that was dehaired by enzyme method was significantly greater than that of the cowhide that was dehaired by mechanical means.

[0052] Example 4: A composite gel with high gel properties, Xinjiang brown cattle hide jelly

[0053] a. Raw material preparation: prepare the cowhide, drinking water, salt, sodium bicarbonate, neutral protease, and xylanase required for the preparation of cowhide jelly;

[0054] b. Dehairing of cowhide: frozen cowhide was taken out and thawed at room temperature, washed to remove excess subcutaneous fascia, and placed in a 5% NaHCO3 solution at a ratio of 1:3 (w:v) to allow it to swell for 16 hours. The cowhide was taken out and rinsed repeatedly. Neutral protease and xylanase were used for enzymatic dehairing at a solid-liquid ratio of 1:6 (w:v), an enzyme concentration of 800 U / mL, a neutral protease to xylanase activity ratio of 3:7, a pH of 7, an enzymatic hydrolysis temperature of 50°C, and an enzymatic hydrolysis time of 4 hours to obtain a dehairing rate of 99.962% of the cowhide.

[0055] c. Boil the glue solution. Add the treated cowhide and drinking water in a mass ratio of 1:3 into the pot and cook at 95°C for 2.5 hours to dissolve the collagen in the cowhide. Filter to remove insoluble matter and add 1% salt by weight of the total glue solution for seasoning to obtain cowhide glue solution.

[0056] d. Filling: Fill the boiled glue liquid into cans using a filling machine;

[0057] e. Sterilization: Place the canned semi-finished product in a 95°C water bath for sterilization for 30 minutes and then seal;

[0058] f. Cooling and forming, the sterilized product is cooled to room temperature and refrigerated at 0-4°C for 12 hours to obtain traditional cowhide jelly with a hardness of 303.001±5.887g and an elasticity of 0.968±0.006.

[0059] Example 5: A composite gel with high gel properties, Xinjiang brown cattle hide jelly

[0060] a. Raw material preparation: prepare the cowhide, drinking water, salt, guar gum, calcium chloride, sodium bicarbonate, neutral protease, and xylanase required for the preparation of cowhide jelly;

[0061] b. Dehairing of cowhide: frozen cowhide was taken out and thawed at room temperature, washed to remove excess subcutaneous fascia, and placed in a 5% NaHCO3 solution at a ratio of 1:3 (w:v) to allow it to swell for 16 hours. The cowhide was taken out and rinsed repeatedly. Neutral protease and xylanase were used for enzymatic dehairing at a solid-liquid ratio of 1:6 (w:v), an enzyme concentration of 800 U / mL, a neutral protease to xylanase activity ratio of 3:7, a pH of 7, an enzymatic hydrolysis temperature of 50°C, and an enzymatic hydrolysis time of 4 hours to obtain a dehairing rate of 99.962% of the cowhide.

[0062] c. Boil the glue solution. Add the treated cowhide and drinking water in a mass ratio of 1:3 into the pot and cook at 90°C for 2.5 hours to dissolve the collagen in the cowhide. Filter to remove insoluble matter, add 1% salt by weight of the entire glue solution for seasoning, then add 0.5% guar gum powder, and cook at 90°C for 20 minutes until dissolved to obtain the cowhide glue solution.

[0063] d. Filling: Fill the boiled glue liquid into cans using a filling machine;

[0064] e. Sterilization: Place the canned semi-finished product in a 95°C water bath for sterilization for 30 minutes and then seal;

[0065] f. Cooling and forming, the sterilized product is cooled to room temperature and refrigerated at 0-4°C for 12 hours to obtain guar gum cowhide jelly with a hardness of 312.277±16.091 and an elasticity of 0.969±0.006.

[0066] Example 6: A composite gel with high gel properties, Xinjiang brown cattle hide jelly

[0067] a. Raw material preparation: prepare the cowhide, drinking water, salt, low acyl gellan gum, calcium chloride, sodium bicarbonate, neutral protease, and xylanase required for the preparation of cowhide jelly;

[0068] b. Dehairing of cowhide: frozen cowhide was taken out and thawed at room temperature, washed to remove excess subcutaneous fascia, and placed in a 5% NaHCO3 solution at a ratio of 1:3 (w:v) to allow it to swell for 16 hours. The cowhide was taken out and rinsed repeatedly. Neutral protease and xylanase were used for enzymatic dehairing at a solid-liquid ratio of 1:6 (w:v), an enzyme concentration of 800 U / mL, a neutral protease to xylanase activity ratio of 3:7, a pH of 7, an enzymatic hydrolysis temperature of 50°C, and an enzymatic hydrolysis time of 4 hours to obtain a dehairing rate of 99.962% of the cowhide.

[0069] c. Boiling the glue solution: add the processed cowhide and drinking water in a mass ratio of 1:3 into a pot and boil at 95°C for 2.5 hours to dissolve the collagen in the cowhide. Filter to remove insoluble matter, add 1% salt by weight of the total glue solution for seasoning, then add 0.5% low acyl gellan gum powder and 0.06% calcium chloride, and boil at 90°C for 20 minutes until dissolved to obtain the cowhide glue solution;

[0070] d. Filling: Fill the boiled glue liquid into cans using a filling machine;

[0071] e. Sterilization: Place the canned semi-finished product in a 95°C water bath for sterilization for 30 minutes and then seal;

[0072] f. Cooling and forming, the sterilized product is cooled to room temperature and refrigerated at 0-4°C for 12 hours to obtain gellan gum jelly with a hardness of 924.331±27.033 and an elasticity of 0.952±0.004.

[0073] Example 7: A composite gel with high gel properties, Xinjiang brown cattle hide jelly

[0074] a. Raw material preparation: prepare the cowhide, drinking water, salt, low acyl gellan gum, guar gum, calcium chloride, sodium bicarbonate, neutral protease, and xylanase required for the preparation of cowhide jelly;

[0075] b. Dehairing of cowhide: frozen cowhide was taken out and thawed at room temperature, washed to remove excess subcutaneous fascia, and placed in a 5% NaHCO3 solution at a ratio of 1:3 (w:v) to allow it to swell for 16 hours. The cowhide was taken out and rinsed repeatedly. Neutral protease and xylanase were used for enzymatic dehairing at a solid-liquid ratio of 1:6 (w:v), an enzyme concentration of 800 U / mL, a neutral protease to xylanase activity ratio of 3:7, a pH of 7, an enzymatic hydrolysis temperature of 50°C, and an enzymatic hydrolysis time of 4 hours to obtain a dehairing rate of 99.962% of the cowhide.

[0076] c. Boiling the glue: adding the treated cowhide and drinking water in a mass ratio of 1:3 into a pot and boiling at 95°C for 2.5 hours to dissolve the collagen in the cowhide. Filtering to remove insoluble matter, adding 1% salt by weight of the total glue for seasoning, then adding 0.5% low acyl gellan gum, 0.5% guar gum powder and 0.06% calcium chloride, boiling at 90°C for 20 minutes until dissolved, to obtain the cowhide glue;

[0077] d. Filling: Fill the boiled glue liquid into cans using a filling machine;

[0078] e. Sterilization: Place the canned semi-finished product in a 95°C water bath for sterilization for 30 minutes and then seal;

[0079] f. Cooling and forming, the sterilized product is cooled to room temperature and refrigerated at 0-4°C for 12 hours to obtain a composite gel cowhide jelly with a hardness of 833.403±48.132 and an elasticity of 0.965±0.008.

[0080] Example 8: Determination of the texture of composite gel Xinjiang brown cattle hide jelly

[0081] Based on the records in the above examples 1 to 7, the technical solutions provided in examples 4, 5, 6 and 7 were used to measure the texture of different cow skin jellies. The jelly was taken out after being refrigerated at 4°C and cut into 2×2×1cm 3After equilibration at room temperature for 10 minutes, the full texture of the sample was measured using the following parameters: a P / 36R probe, a speed of 1 mm / s before, during, and after the test, a deformation degree of 30%, and a trigger force of 5 gf. The sample's texture properties, including hardness, elasticity, and chewiness, were measured three times. As shown in Table 1, the results show that the low-acyl gellan gum jelly had the highest hardness, a 67.22% increase compared to traditional jelly, while its corresponding elasticity, cohesion, and resilience were the lowest, indicating that low-acyl gellan gum jelly has high hardness but is also brittle and prone to breakage. In the composite gel jelly group with the addition of guar gum, all three texture properties were improved to varying degrees, indicating that the addition of guar gum can, to a certain extent, alleviate the high hardness caused by low-acyl gellan gum, improving both taste and texture. In summary, the addition of both gels increases the overall gel strength of traditional jelly and improves its gel properties.

[0082] Table 1: Full texture parameters of different cowhide jelly

[0083] Example 4 Example 5 Example 6 Example 7 hardness <![CDATA[303.001±5.887 a ]]> <![CDATA[312.277±16.091 a ]]> <![CDATA[924.331±27.033 b ]]> <![CDATA[833.403±48.132 c ]]> elasticity <![CDATA[0.968±0.006 a ]]> <![CDATA[0.969±0.006 a ]]> <![CDATA[0.952±0.004 b ]]> <![CDATA[0.965±0.008 ab ]]> Cohesion <![CDATA[0.936±0.009 a ]]> <![CDATA[0.935±0.008 a ]]> <![CDATA[0.844±0.003 b ]]> <![CDATA[0.867±0.002 c ]]> Adhesion <![CDATA[283.678±4.165 a ]]> <![CDATA[291.740±12.513 a ]]> <![CDATA[780.102±20.520 b ]]> <![CDATA[722.681±42.512 c ]]> chewability <![CDATA[274.760±5.290 a ]]> <![CDATA[282.415±10.107 a ]]> <![CDATA[742.983±20.390 b ]]> <![CDATA[697.257±35.670 b ]]> Resilience <![CDATA[0.783±0.030 a ]]> <![CDATA[0.742±0.030 a ]]> <![CDATA[0.589±0.004 b ]]> <![CDATA[0.604±0.009 b ]]>

[0084] Example 9: Determination of properties of composite gel Xinjiang brown cattle hide jelly

[0085] Based on the descriptions in Examples 1 to 7 above, the technical solutions provided in Examples 4, 5, 6, and 7 were used, and the prepared jelly was placed on a 40 mm diameter parallel plate of a rotational rheometer and equilibrated at room temperature for 10 min, with a parallel plate gap of 0.5 mm and a set temperature of 25° C. The composite viscosity, storage modulus (G'), and loss modulus (G") were measured at an angular velocity of 0.1 to 100 rad / s. Figure 2 As shown in (A), with the increase of angular velocity, the complex viscosity decreases with the increase of oscillation frequency. The four jellies exhibit shear thinning behavior and are all typical pseudoplastic fluids. The original jelly has the lowest complex viscosity. After the addition of edible polysaccharide gel, the complex viscosity is improved. Among them, the complex viscosity of gellan gum cowhide jelly is the highest, followed by the composite gel jelly, which is consistent with the above texture results. The addition of gellan gum can significantly increase the hardness of cowhide jelly and reduce fluidity. The reason for shear thinning is the high-speed shearing action, which destroys the interaction between molecules in the colloid, destroys the molecular chains in the jelly, and weakens the entanglement between molecules. After the addition of exogenous polysaccharides, the increase in the viscosity of the jelly indicates that the interaction between the blends is increased, and the exogenously added gel polysaccharide is entangled and cross-linked with the collagen, the main component of the jelly. As shown in Figure 2 (B) with Figure 2As shown in (C), the G' (storage modulus) of the four types of jellies is greater than G" (loss modulus), indicating that the four types of jellies are mainly composed of elastic components and are in a gel state. The G' of the jelly with gellan gum added is much higher than that of the jelly with guar gum added and the traditional jelly, indicating that the addition of gellan gum can make the jelly more viscoelastic and increase the strain resistance of the system. 2 In the high-frequency region, the increasing trend of G" increases significantly, indicating that the angular velocity has a greater impact on the viscosity characteristics of the four colloids than the elastic characteristics, especially in the jelly with gellan gum added. This is because the brittle structure formed by the gellan gum is easily destroyed under high-frequency angular velocity.

[0086] Example 10: Determination of water holding capacity of composite gel Xinjiang brown cattle hide jelly

[0087] Based on the records in Examples 1 to 7 above, the technical solutions provided in Examples 4, 5, 6, and 7 were used to measure the water holding capacity of four kinds of jelly using a centrifuge. About 5 g of different jelly were weighed, wrapped with three layers of filter paper, and placed in a 50 mL centrifuge tube for centrifugation. The centrifugation conditions were 5000 × g for 15 min. The mass of the sample before centrifugation was recorded as m, and the mass of the sample after centrifugation was recorded as M. The calculation was performed according to the following formula. The results are shown in Figure 2. Figure 3 As shown in the figure, guar gum jelly has the highest water holding capacity, followed by the composite gel jelly group. Guar gum has higher order than gelatin, but lower crystallinity. After being added, it can form a denser gel network to lock in moisture and improve the water holding capacity of jelly.

[0088]

[0089] Example 11: Determination of the strength of Xinjiang brown cattle hide composite gel cryogel

[0090] Based on the descriptions in Examples 1 to 7 above, the technical solutions provided in Examples 4, 5, 6, and 7 were applied. 15 mL of cowhide soup was poured into a 25 mL beaker and placed at 4°C for 24 hours to freeze. The mixture was then taken out and equilibrated at room temperature for 10 minutes. A P / 5 probe was used. The speed before, during, and after the test was 1 mm / s, and the puncture distance was 4 mm. The gel strength was recorded. Figure 4 As shown, the change in gel strength is consistent with the change in hardness. The addition of both polysaccharide colloids can improve the gel strength of the jelly. In particular, the gel strength of Example 6 is the highest, reaching 900.243g, indicating that the addition of polysaccharide colloid can form a more stable complex with the protein in the jelly.

[0091] Example 11: Analysis of thermal stability of composite gel Xinjiang brown cattle hide jelly

[0092] The thermal stability of the four kinds of cowhide jellies provided in Example 4, Example 5, Example 6 and Example 7 was analyzed using a synchronous thermal analyzer. Figure 5 As shown in (C), the peaks of traditional cowhide jelly and guar gum cowhide jelly are narrower, while the peaks of gellan gum cowhide jelly and composite gel cowhide jelly are wider. The melting temperature and thermal enthalpy of composite gel cowhide jelly are the highest, reaching 156.056℃ and 439.298J / g respectively, indicating that the addition of the two edible polysaccharides is conducive to the formation of a compact and stable gel network in cowhide jelly, requiring higher energy than traditional methods to induce its denaturation, thereby improving the stability of the product at higher temperatures and expanding its processing application range. Figure 5 The TG results of (A) show that significant weight loss changes occurred between 40 and 200 ° C. All four jellies lost about 80% of their weight. Water, as the main component of jellies, has the ability to interact with the polymer chains in the colloid components of the jellies to a certain extent, which reflects the stability of the product. After adding gellan gum, the end temperature of weight loss shifted from 158.056 ° C of traditional cow skin jelly to 186.307 ° C. This is because the carboxyl groups between adjacent double helices of gellan gum are 2+ Under the action of the heat, the connection becomes stronger and a thermally irreversible gel is produced. Figure 5 (B) The DTG results showed the same trend as the DSC results. The traditional cowhide jelly and guar gum cowhide jelly showed narrower peaks compared with the gellan gum cowhide jelly and the composite gel cowhide jelly, indicating that the quality change of the jelly with the addition of gellan gum was slower as the temperature continued to rise. In particular, the DTG peak of the composite gel cowhide jelly reached 144.056℃, and the entanglement in the colloid was greater, showing relatively strong thermal stability.

[0093] Example 12: Determination of melting temperature of composite gel Xinjiang brown cattle hide jelly

[0094] The different processed cowhide jelly soups provided in Example 4, Example 5, Example 6, and Example 7 were poured into glass test tubes, condensed at 4°C for 24 hours, and then taken out. A small steel ball was placed on the surface of the cowhide jelly, and the mixture was placed in a constant temperature water bath. The temperature was raised from 20°C to 99°C at a rate of 1°C / min. The melting temperature was recorded when the small steel ball sank into the surface of the jelly. A small steel ball was placed in the test tube of the molten cowhide soup and shaken at room temperature. The solidification temperature was recorded when the steel ball stopped moving. Figure 6 As shown in the figure, the solidification and melting temperatures of the four kinds of cowhide jelly, the solidification and melting temperatures of the cowhide jelly with low acyl gellan gum changed significantly (P<0.05), and this difference was attributed to the difference between low acyl gellan gum and Ca 2+Irreversibility of gel formation. The melting temperature reflects the energy required to destroy the colloidal gel network, while the solidification temperature reflects the application performance after annealing. The melting and solidification temperatures did not change significantly after the addition of guar gum due to the poor thermal stability of guar gum. The melting and solidification temperatures of the composite gel jelly both reached maximum values of 53.63±0.95°C and 36.6±0.36°C, respectively. The significant difference between the two temperatures is due to the high thermal hysteresis of low-acyl gellan gum.

[0095] Example 13: Determination of freeze-thaw water loss rate of composite gel Xinjiang brown cattle hide jelly

[0096] The different processed cowhide jellies provided in Examples 4, 5, 6 and 7 were placed in a 20°C freezer for 24 hours, taken out and thawed at room temperature, and the surface moisture was absorbed with filter paper. After three freeze-thaw cycles, the freeze-thaw water loss rate was calculated. Figure 7 Results showed that among the four different types of kraft jelly, gellan gum kraft jelly released the most water after three freeze-thaw cycles, with a water loss rate of 18.999%. The formation of larger ice crystals and the resulting brittle structure made the water-wrapped interface more susceptible to rupture, leading to a large amount of water loss upon dissolution. Adding guar gum reduced the freeze-thaw water loss rate, reaching the lowest of 4.492% for the guar gum kraft jelly. Guar gum densifies the gel network, restricting ice crystal growth and reducing the damage to the gel structure caused by larger ice crystals. Furthermore, the abundant free hydroxyl groups in guar gum enhance water retention, reducing freeze-thaw damage and improving the freeze-thaw stability of the jelly. In summary, the addition of guar gum significantly reduces freeze-thaw water loss while simultaneously improving the gel strength of the jelly, imparting better cold processing properties.

[0097] Example 14: Microscopic results of composite gel Xinjiang brown cattle hide jelly

[0098] The different treated cowhide jelly provided in Example 4, Example 5, Example 6 and Example 7 were observed using a scanning electron microscope (SEM). Figure 8 As shown, the surface of the gel jelly with gellan gum added exhibits a coarser structural skeleton than that of traditional cowhide jelly, with relatively large and uneven cavities. This suggests that gellan gum may have become the primary continuous phase in the jelly, demonstrating the enhanced brittleness and hardness brought about by the addition of gellan gum. The surface of the gel jelly with guar gum added exhibits a greater number of dense, small pores within the three-dimensional network of traditional cowhide jelly. This phenomenon is more pronounced in the images of the composite gel jelly. The coarser network created by the addition of gellan gum forms a denser gel network, with smaller pores allowing for greater entanglement with water. This also explains the superior water retention and thaw resistance of the gel jelly with guar gum.

[0099] Example 15: Determination of protein digestibility of composite gel Xinjiang brown cattle hide jelly

[0100] For the differently treated cowhide jellies provided in Examples 4 and 7, 2 g of the cowhide jellies were minced, added to 20 mL of artificial simulated gastric fluid, and digested at 37° C., 180 rpm, and shaken for 2 h. After gastric digestion, the pH of the simulated gastric digestive fluid was adjusted to 6.8±0.2 with 0.9 mol / L NaHCO 3 , and 20 mL of artificial simulated intestinal fluid was added. The mixture was shaken at 37° C., 180 rpm, and digested for 2 h. Samples were taken at different times to determine the protein digestibility, which was calculated according to the following formula:

[0101]

[0102] like Figure 9 As shown in the figure, the digestibility of composite gel jelly is lower than that of traditional jelly during the gastric digestion stage, indicating that the addition of hydrocolloid can delay the digestion of jelly.

[0103] Example 16: Determination of storage properties of composite gel Xinjiang brown cattle hide jelly

[0104] The compound gel jelly was stored at 4°C, 25°C, and 35°C, and the volatile basic nitrogen (TVB-N) value and actual sensory score of the main component protein in the compound gel jelly were measured. The samples at 35°C were measured every 3 days, the samples at 25°C were measured every 6 days, and the samples at 4°C were measured every 9 days. When the TVB-N value exceeds the inspection standard and the sensory score is less than 60 points, it is regarded as the end of the shelf life. The changes in quality indicators during storage were measured, and the Arrhenius model was established to predict its shelf life. The changes in TVB-N values in compound gel jelly at different ambient temperatures are as follows Figure 10 As shown in (A), the changes in TVB-N values under the three temperature environments are consistent, and all show a corresponding increasing trend with the increase in storage days. Among them, the TVB-N value at 35°C increases most rapidly, reaching 8.87 mg / 100g at the end of storage. At the end of storage at 25°C, the TVB-N value reaches 7.7 mg / 100g, and at 4°C it reaches 4.62 mg / 100g. Figure 10 (B) Sensory scores of the gel-jelly decreased at all storage temperatures. At 35°C, the actual sensory score decreased, with noticeable water separation occurring after 12 days. On the 15th day, an unpleasant odor began to develop due to chemical reactions such as the decomposition of lipids and proteins in the jelly, causing the score to drop below 60. At 25°C, this period was extended by approximately 9 days, and with continued storage, a slight white clump began to appear within the jelly after 24 days, with the sensory score dropping to 59.3. At 4°C, the trend was more stable, with a smaller downward trend, indicating that gel-jelly stored at 4°C was better protected from deterioration. This suggests that higher temperatures have a greater impact on the storage quality of jelly.

[0105] The first-order kinetic model (Equation 1) has been widely used in the study of food spoilage reactions.

[0106] A=A0e Kt (Formula 1)

[0107] Where A is the index level of the product at a certain moment of storage; A0 is the index level of the product at the initial moment; K is the reaction rate constant; t is the storage time of the product

[0108] The linear relationship between TVB-N value and storage time during storage at 35, 25, and 4°C was obtained by taking the logarithm of both sides of (Equation 1) (Equation 2) and performing regression fitting, as shown in Table 2.

[0109] lnA=lnA0+kt (Equation 2)

[0110] Table 2: Kinetic parameters of the primary quality change of TVB-N value in composite gel jelly at different temperatures

[0111] Temperature / ℃ Regression equation Rate constant / k <![CDATA[Coefficient of determination / R 2 > 35 y=0.0821x+1.0781 0.0821 0.9286 25 y=0.0414x+0.9763 0.0414 0.9206 4 Y=0.016X+0.8963 0.016 0.9449

[0112] The relationship between ambient temperature and mass rate change conforms to the Arrhenius equation (Equation 3).

[0113]

[0114] Where k0 is the pre-exponential factor; Ea is the reaction activation energy, J / mol; R is the gas constant 80.314, J / (mol·K); K is the absolute temperature of food storage

[0115] Taking the logarithm of both sides of (Equation 3) yields Equation 4, where lnk and 1 / T show a linear regression relationship. The TVB-N values at three different temperatures of 35, 25, and 4°C in the storage experiment are fitted, and the results are shown in Table 5-2. The activation energy Ea and pre-exponential factor k0 of the model are calculated to be 37.8395 kJ / mol and 197.4025 kJ / mol, respectively. Substituting them into (Equation 1) yields (Equation 5).

[0116]

[0117] Table 3: Arrhenius curve model and parameters of TVB-N value of compound gel jelly

[0118] index Ea(J / mol) <![CDATA[Pre - exponential factor k0]]> Regression equation <![CDATA[Coefficient of determination / R 2 > TVB-N 37839.5082 197402.4861 y=-4551.3x+12.193 0.9854

[0119] Substituting the TVB-N value A required by the national standard and the initial TVB-N value A0 obtained from the experiment, the shelf life of the composite gel jelly at 4°C was found to be 114 days.

[0120] The preparation method of the present invention adds low-acyl gellan gum to add a rigid structure to traditional jelly, improving its hardness and gel strength. Under the action of calcium chloride, a thermally irreversible gel is generated, thereby improving the thermal stability of the jelly. The addition of guar gum can make the jelly gel network denser, more entangled with the water in the gel, improve the jelly's ability to resist external forces, and simultaneously reduce the formation of large ice crystals during frozen storage, reducing the freeze-thaw water loss rate. Compared with traditional jelly, it has thermal stability and freeze-thaw resistance, promotes the processing and application of jelly, and improves product quality. The final product obtained by the technology used in the present invention has good gel properties, high stability, and is not easy to melt.

[0121] The above embodiments are merely examples for the purpose of illustrating the present invention and are not intended to limit the embodiments. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all embodiments here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A composite gel Xinjiang brown cowhide jelly, characterized in that: The composite gel Xinjiang brown cowhide jelly is obtained from Xinjiang brown cowhide, neutral protease, xylanase, drinking water, salt, low acyl gellan gum, guar gum, calcium chloride and sodium bicarbonate.

2. A method for preparing a composite gel Xinjiang brown cowhide jelly, characterized in that: The method comprises the following steps: a. Prepare the necessary Xinjiang brown cattle hides, drinking water, salt, low acyl gellan gum, guar gum, calcium chloride, sodium bicarbonate, neutral protease, and xylanase; b. Frozen cowhide was taken out and thawed at room temperature, washed to remove excess subcutaneous fascia, and placed in a 5% NaHCO3 solution at a ratio of 1:3 (w:v) for 16 hours. After repeated rinsing, neutral protease and xylanase were used for enzymatic dehairing. The material-liquid ratio was set to , and a composite enzyme solution of neutral protease and xylanase was added. The enzymatic hydrolysis temperature was 50 ° C and the enzymatic hydrolysis time was 4 hours to obtain a dehairing rate of 99.962% dehaired cowhide. c. Add the treated cowhide and drinking water in a 1:3 mass ratio to a double-layer pot and cook at 95°C for 2.5h to dissolve the collagen in the cowhide. Filter to remove insoluble matter, add salt for seasoning, then add low acyl gellan gum and guar gum powder and calcium chloride, and cook at 90°C for 20min until dissolved to obtain cowhide glue; d. Fill the boiled glue into cans using a filling machine; e. Place the canned semi-finished product in a 95°C water bath for sterilization for 30 minutes and then seal; f. The sterilized product was cooled to room temperature and refrigerated at 0-4°C for 12 hours to obtain a composite gel cowhide jelly with a hardness of 833.403±48.132g and an elasticity of 0.965±0.

008.

3. The method for preparing the composite gel Xinjiang brown cowhide jelly according to claim 2, wherein: In step b, the material-liquid ratio is 1:6 (w:v).

4. The method for preparing the composite gel Xinjiang brown cowhide jelly according to claim 2, wherein: In step b, the enzyme solution concentration is 800 U / mL, the ratio of neutral protease to xylanase activity is 3:7, and the pH is 7.

5. The method for preparing the composite gel Xinjiang brown cowhide jelly according to claim 2, wherein: In step b, the enzymolysis temperature is 50° C. and the enzymolysis is carried out for 4 h.

6. The method for preparing the composite gel Xinjiang brown cowhide jelly according to claim 2, wherein: In step c, 1% salt based on the weight of the entire glue solution is added for seasoning.

7. The method for preparing the composite gel Xinjiang brown cowhide jelly according to claim 2, wherein: In step c, 0.5% low acyl gellan gum is added.

8. The method for preparing the composite gel Xinjiang brown cowhide jelly according to claim 2, wherein: In step c, 0.5% guar gum powder was added.

9. The method for preparing the composite gel Xinjiang brown cowhide jelly according to claim 2, wherein: In step c, 0.06% calcium chloride was added.

10. Use of the preparation method of the composite gel Xinjiang brown cowhide jelly according to any one of claims 2 to 9 in preparing composite gel Xinjiang brown cowhide jelly.

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