An oyster protein gel, its preparation method and application

Abstract

This invention discloses a high-strength oyster protein gel, its preparation method, and its applications, belonging to the field of protein gel preparation technology. Using oyster meat as raw material, this invention obtains oyster protein isolate through an alkali-dissolution and acid-precipitation method, and pre-coagulates the oyster protein isolate at ultra-long-term low temperatures. High-temperature induction of deep cross-linking significantly improves the gel properties of the oyster protein isolate. The prepared oyster protein isolate gel exhibits characteristics such as smooth surface, high gel strength, and high elasticity. This invention utilizes only temperature to control the aggregation degree, conformation, and intermolecular interactions of oyster proteins, thereby inducing the formation of a high-quality protein gel. Furthermore, the preparation process of this invention involves no organic chemical reagents or food additives, and no NaCl is added, resulting in a pure, safe, and simple oyster protein isolate gel formulation with high application value and industrialization potential.

Description

Technical Field

[0001] This invention relates to the field of protein gel preparation technology, and in particular to a high-strength oyster protein gel, its preparation method, and its application. Background Technology

[0002] Oysters are a high-yield shellfish, rich in protein and containing a complete range of amino acids, making them a high-quality aquatic animal protein resource. Currently, oysters are mainly sold fresh as seafood, with limited processed products; only a small portion is processed into seasonings or oyster peptide-based health supplements. However, the existing sales methods and products of oysters cannot meet people's demand for convenient and healthy foods. Gel properties are one of the most important functional properties of proteins and a key factor in regulating the quality characteristics of gel-based products. Small-packaged gel-based foods such as fish sausages, crab sticks, and fish tofu, based on protein gels, are becoming increasingly popular.

[0003] However, the gelling properties of oyster protein are a limiting factor in the application of oysters in gelled foods, and no oyster protein-based gel products are currently available on the market. Therefore, there is an urgent need in this field to find an economical and effective method to prepare oyster protein gels with excellent gelling properties, broaden their application in food, and meet the public's demand for novel shellfish gel products.

[0004] Temperature-induced gelation is the most important and widely used method for preparing protein gels. In this process, proteins denature and unfold under heat, exposing nonpolar residues, and subsequently aggregate through covalent and nonvalent interactions to form an ordered three-dimensional gel network structure. However, inappropriate heat treatment conditions significantly affect the gelation behavior of proteins. Too low a temperature may result in insufficient protein cross-linking, affecting the stability of the gel structure. Too high a temperature may cause proteins to form irregular, large particles before orderly aggregation, ultimately forming large, rough cavities, disrupting the three-dimensional gel network structure, and adversely affecting product quality.

[0005] Therefore, preparing high-strength oyster protein gels to solve the problems of unstable performance and insufficient strength of traditional oyster protein gels is a promising method. Summary of the Invention

[0006] The purpose of this invention is to provide a high-strength oyster protein gel, its preparation method, and its application, in order to solve the problems existing in the prior art. This invention utilizes ultra-long-term low-temperature pre-coagulation of oyster protein isolate and high-temperature induction of deep cross-linking to prepare an oyster protein gel with characteristics such as smooth surface, high gel strength, and high elasticity.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides a method for preparing a high-strength oyster protein gel, comprising the following steps:

[0009] Oyster protein isolate was obtained by alkali dissolution and acid precipitation using oyster meat as raw material;

[0010] Oyster protein isolate was prepared into a protein suspension with a mass fraction of 1.5% and allowed to stand at 25±5℃ for 24h~48h to coagulate.

[0011] The solidified oyster protein isolate is heated at 70-90℃ for 20 minutes and then cooled to obtain the final product.

[0012] Optionally, the alkali dissolution and acid precipitation includes: mixing oyster meat with water at a mass-to-volume ratio of 1g:1~5mL, and homogenizing at a speed of 5000~10000rpm for 2~5min to obtain an oyster meat homogenate;

[0013] Adjust the pH of the oyster meat homogenate to 8-12, extract for 1-4 hours, and centrifuge to obtain the alkaline extraction supernatant;

[0014] Adjust the pH of the alkaline extraction supernatant to 5.5, and centrifuge to obtain the precipitate;

[0015] The precipitate was redissolved in water at a ratio of 1g:1~2mL, the pH was adjusted to neutral, and the product was freeze-dried to obtain oyster protein isolate.

[0016] Optionally, the centrifugation is performed at 4°C, 10000~14000×g for 10~20 min.

[0017] Optionally, the protein suspension is first homogenized at a speed of 5000~10000 rpm for 2~5 min, and then allowed to stand at 4°C to ensure that the protein is fully hydrated.

[0018] Alternatively, the mixture can be allowed to stand at 25±5℃ for 24 hours to solidify.

[0019] Alternatively, the coagulated oyster protein isolate can be heated at 80°C for 20 minutes.

[0020] The present invention also provides a high-strength oyster protein gel obtained according to the preparation method described herein.

[0021] The present invention also provides the application of the high-strength oyster protein gel in the preparation of protein gel foods.

[0022] The present invention also provides a protein gel food comprising the aforementioned high-strength oyster protein gel.

[0023] The present invention discloses the following technical effects:

[0024] This invention uses oyster meat as raw material and obtains oyster protein isolate through an alkali-dissolution and acid-precipitation method. It then utilizes ultra-long-duration low-temperature pre-coagulation of the oyster protein isolate followed by high-temperature-induced deep cross-linking, significantly improving the gel properties of the oyster protein isolate. The prepared oyster protein isolate gel exhibits smooth surface, high gel strength, and high elasticity. This invention can control the aggregation degree, conformation, and intermolecular interactions of oyster proteins using only temperature, thereby inducing the formation of a high-quality protein gel. Furthermore, the preparation process of this invention involves no organic chemical reagents or food additives, and no NaCl is added, resulting in a pure, safe, and simple oyster protein isolate gel formulation with high application value and industrialization potential. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 Visual representations of oyster protein isolate gels from Examples 1-5 and Comparative Examples 1-3;

[0027] Figure 2 The bar chart shows the gel strength of the oyster protein isolate gels in Examples 1-5 and Comparative Example 1.

[0028] Figure 3 Bar charts showing the hardness of oyster protein isolate gels in Examples 1-5 and Comparative Example 1;

[0029] Figure 4 The following are elastic bar graphs of oyster protein isolate gels from Examples 1-5 and Comparative Example 1;

[0030] Figure 5 Bar graphs showing the water retention properties of oyster protein isolate gels in Examples 1-5 and Comparative Example 1;

[0031] Figure 6 The microstructure diagrams are of the oyster protein isolate gels in Examples 1-5 and Comparative Example 1;

[0032] In the above figures, 25℃ represents Comparative Example 1, 70℃ represents Example 1, 75℃ represents Example 2, 80℃ represents Example 3, 85℃ represents Example 4, and 90℃ represents Example 5. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] Traditional two-stage heating is a common heating method for aquatic gel-based foods such as surimi. First, the product is heated to 40–50°C to solidify, then further heated at 80–90°C, ultimately forming a cooked surimi gel product with elasticity and texture. Existing technologies include methods for enhancing gel strength by staged heating for fish and scallop meat. CN108617848A discloses a method for improving the gel strength of ribbonfish surimi. This method first prepares ribbonfish surimi, with a first-stage heating temperature of 35–65°C for 10–90 min, and a second-stage heating temperature of 60–90°C for 15–30 min. By controlling the heating time and temperature, ribbonfish surimi with satisfactory gel strength can be obtained. Wang Yifan (Analysis of the Formation Law and Performance of Water Bath Thermo-Induced Gel in Bay Scallop [J / OL]. Food Industry Technology, 1-21) et al. found that compared with one-stage thermo-induction, two-stage induction, especially at 45℃ (30 min) and 95℃ (20 min), is more conducive to the unfolding of myofibril proteins in bay scallop molluscs, forming an ordered and compact gel network structure. However, due to the large amount of water-soluble protein in oyster protein and the special composition and structure, oyster protein undergoes flocculation and precipitation directly after a short period of low-temperature treatment (10-120 min) in the traditional two-stage heating process, followed by high-temperature heating, or forms a rough and fragile gel with a large loss of water. This limits the application of oyster protein in gel products. However, through extensive experimental screening, this invention found that ultra-long-term low-temperature pretreatment can overcome the above shortcomings and enable oyster protein to form high-strength, high-water-content protein gels at concentrations far lower than those commonly used for gel formation by other meat proteins (50 mg / mL) without the need for the addition of high concentrations of NaCl. See the following examples for details.

[0039] Example 1: A method for preparing a high-strength oyster protein isolate gel

[0040] Oyster meat was used as raw material to obtain oyster protein isolate by alkaline dissolution and acid precipitation: fresh oyster meat was washed, seaweed was removed and crushed, and oyster meat was mixed with deionized water at a ratio of 1:1~5 (g / mL) (1:3 in this example) and homogenized at 5000~10000 rpm for 2~5 min (10000 rpm for 2 min in this example).

[0041] Add NaOH solution to the oyster meat homogenate to adjust the pH to 8-12 (10 in this example), extract with magnetic stirring for 1-4 hours (2 hours in this example), centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain alkaline extraction supernatant; add HCl solution to the alkaline extraction supernatant to adjust the pH to 5.5, let stand for 1 hour, centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain precipitate; redissolve the precipitate in water at a ratio of 1:1-2 (g / mL) (1:1 in this example), adjust the pH to neutral, freeze dry to obtain oyster protein isolate.

[0042] Oyster protein isolate was prepared into a protein suspension with a mass fraction of 1.5% using deionized water, homogenized at 10,000 rpm for 2 minutes using a homogenizer, and then incubated overnight at 4°C to ensure that the protein was fully dissolved and hydrated.

[0043] Weigh 6g of oyster protein isolate suspension into a 10mL beaker, seal it with plastic wrap, and place it in an incubator at 25±5℃ for 24h~48h (24h in this example) to allow the protein to coagulate.

[0044] The coagulated oyster protein isolate was placed in a water bath and heated at 70°C for 20 min to induce thermal induction and prepare an oyster protein isolate gel. The gel was immediately placed in ice water to cool, and then refrigerated at 4°C overnight. The next day, the gel was removed and allowed to return to room temperature to obtain the oyster protein isolate gel. Its appearance was observed, and the gel strength, hardness, elasticity, and water retention were measured.

[0045] Example 2: A method for preparing a high-strength oyster protein isolate gel

[0046] Oyster meat was used as raw material to obtain oyster protein isolate by alkaline dissolution and acid precipitation: fresh oyster meat was washed, seaweed was removed and crushed, and oyster meat was mixed with deionized water at a ratio of 1:1~5 (g / mL) (1:3 in this example) and homogenized at 5000~10000 rpm for 2~5 min (10000 rpm for 2 min in this example).

[0047] Add NaOH solution to the oyster meat homogenate to adjust the pH to 8-12 (10 in this example), extract with magnetic stirring for 1-4 hours (2 hours in this example), centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain alkaline extraction supernatant; add HCl solution to the alkaline extraction supernatant to adjust the pH to 5.5, let stand for 1 hour, centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain precipitate; redissolve the precipitate in water at a ratio of 1:1-2 (g / mL) (1:1 in this example), adjust the pH to neutral, freeze dry to obtain oyster protein isolate.

[0048] Oyster protein isolate was prepared into a protein suspension with a mass fraction of 1.5% using deionized water, homogenized at 10,000 rpm for 2 minutes using a homogenizer, and then incubated overnight at 4°C to ensure that the protein was fully dissolved and hydrated.

[0049] Weigh 6g of oyster protein isolate suspension into a 10mL beaker, seal it with plastic wrap, and place it in an incubator at 25±5℃ for 24h~48h (24h in this example) to allow the protein to coagulate.

[0050] The coagulated oyster protein isolate was placed in a water bath and heated at 75°C for 20 minutes to prepare a heat-induced oyster protein isolate gel. The gel was immediately cooled in ice water and then refrigerated overnight at 4°C. The next day, the gel was removed and allowed to return to room temperature to obtain the oyster protein isolate gel. Its appearance was observed, and its gel strength, hardness, elasticity, and water retention were measured.

[0051] Example 3: A method for preparing a high-strength oyster protein isolate gel

[0052] Oyster meat was used as raw material to obtain oyster protein isolate by alkaline dissolution and acid precipitation: fresh oyster meat was washed, seaweed was removed and crushed, and oyster meat was mixed with deionized water at a ratio of 1:1~5 (g / mL) (1:3 in this example) and homogenized at 5000~10000 rpm for 2~5 min (10000 rpm for 2 min in this example).

[0053] Add NaOH solution to the oyster meat homogenate to adjust the pH to 8-12 (10 in this example), extract with magnetic stirring for 1-4 hours (3 hours in this example), centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain alkaline extraction supernatant; add HCl solution to the alkaline extraction supernatant to adjust the pH to 5.5, let stand for 1 hour, centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain precipitate; redissolve the precipitate in water at a ratio of 1:1-2 (g / mL) (1:1 in this example), adjust the pH to neutral, freeze dry to obtain oyster protein isolate.

[0054] Oyster protein isolate was prepared into a protein suspension with a mass fraction of 1.5% using deionized water, homogenized at 10,000 rpm for 2 minutes using a homogenizer, and then incubated overnight at 4°C to ensure that the protein was fully dissolved and hydrated.

[0055] Weigh 6g of oyster protein isolate suspension into a 10mL beaker, seal it with plastic wrap, and place it in an incubator at 25±5℃ for 24h~48h (24h in this example) to allow the protein to coagulate.

[0056] The coagulated oyster protein isolate was placed in a water bath and heated at 80°C for 20 minutes to prepare a heat-induced oyster protein isolate gel. The oyster protein isolate gel was immediately placed in ice water to cool, and then refrigerated at 4°C overnight. The next day, the gel was removed and allowed to return to room temperature to obtain the oyster protein isolate gel. Its appearance was observed, and the gel strength, hardness, elasticity, and water retention were measured.

[0057] Example 4: A method for preparing a high-strength oyster protein isolate gel

[0058] Oyster meat was used as raw material to obtain oyster protein isolate by alkaline dissolution and acid precipitation: fresh oyster meat was washed, seaweed was removed and crushed, and oyster meat was mixed with deionized water at a ratio of 1:1~5 (g / mL) (1:3 in this example) and homogenized at 5000~10000 rpm for 2~5 min (10000 rpm for 2 min in this example).

[0059] Add NaOH solution to the oyster meat homogenate to adjust the pH to 8-12 (10 in this example), extract with magnetic stirring for 1-4 hours (2 hours in this example), centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain alkaline extraction supernatant; add HCl solution to the alkaline extraction supernatant to adjust the pH to 5.5, let stand for 1 hour, centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain precipitate; redissolve the precipitate in water at a ratio of 1:1-2 (g / mL) (1:1 in this example), adjust the pH to neutral, freeze dry to obtain oyster protein isolate.

[0060] Oyster protein isolate was prepared into a protein suspension with a mass fraction of 1.5% using deionized water, homogenized at 10,000 rpm for 2 minutes using a homogenizer, and then incubated overnight at 4°C to ensure that the protein was fully dissolved and hydrated.

[0061] Weigh 6g of oyster protein isolate suspension into a 10mL beaker, seal it with plastic wrap, and place it in an incubator at 25±5℃ for 24h~48h (24h in this example) to allow the protein to coagulate.

[0062] The coagulated oyster protein isolate was placed in a water bath and heated at 85°C for 20 minutes to prepare a heat-induced oyster protein isolate gel. The gel was immediately cooled in ice water and then refrigerated overnight at 4°C. The next day, the gel was removed and allowed to return to room temperature to obtain the oyster protein isolate gel. Its appearance was observed, and its gel strength, hardness, elasticity, and water retention were measured.

[0063] Example 5: A method for preparing a high-strength oyster protein isolate gel

[0064] Oyster meat was used as raw material to obtain oyster protein isolate by alkaline dissolution and acid precipitation: fresh oyster meat was washed, seaweed was removed and crushed, and oyster meat was mixed with deionized water at a ratio of 1:1~5 (g / mL) (1:3 in this example) and homogenized at 5000~10000 rpm for 2~5 min (10000 rpm for 2 min in this example).

[0065] Add NaOH solution to the oyster meat homogenate to adjust the pH to 8-12 (10 in this example), extract with magnetic stirring for 1-4 hours (2 hours in this example), centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain alkaline extraction supernatant; add HCl solution to the alkaline extraction supernatant to adjust the pH to 5.5, let stand for 1 hour, centrifuge at 10000-14000×g for 10-20 minutes at 4°C (20 minutes at 13800×g in this example) to obtain precipitate; redissolve the precipitate in water at a ratio of 1:1-2 (g / mL) (1:1 in this example), adjust the pH to neutral, freeze dry to obtain oyster protein isolate.

[0066] Oyster protein isolate was prepared into a protein suspension with a mass fraction of 1.5% using deionized water, homogenized at 10,000 rpm for 2 minutes using a homogenizer, and then incubated overnight at 4°C to ensure that the protein was fully dissolved and hydrated.

[0067] Weigh 6g of oyster protein isolate suspension into a 10mL beaker, seal it with plastic wrap, and place it in an incubator at 25±5℃ for 24h to allow the protein to coagulate.

[0068] The coagulated oyster protein isolate was placed in a water bath and heated at 90°C for 20 minutes to prepare a heat-induced oyster protein isolate gel. The oyster protein isolate gel was immediately placed in ice water to cool, and then refrigerated at 4°C overnight. The next day, the gel was removed and allowed to return to room temperature to obtain the oyster protein isolate gel. Its appearance was observed, and the gel strength, hardness, elasticity, and water-holding capacity were measured.

[0069] Comparative Example 1

[0070] Same as Example 1, except that: only the oyster protein isolate suspension was placed in an incubator at 25±5℃ and left to stand for 24 hours to allow the protein to coagulate, without any subsequent high-temperature heating.

[0071] Comparative Example 2

[0072] Same as Example 3, except that: a traditional two-stage water bath heating method is used, the oyster protein isolate suspension is heated at 25±5℃ for only 30 minutes, and then heated at 80℃ for 20 minutes.

[0073] Comparative Example 3

[0074] Same as Comparative Example 2, except that the concentration of oyster protein isolate was 5%.

[0075] result

[0076] 1. Gel state

[0077] Figure 1The images show the oyster protein isolate gels in Examples 1-5 and Comparative Examples 1-3. It can be seen that the low-concentration oyster protein isolate heated by the conventional two-stage water bath cannot form a gel (Comparative Example 2), but instead undergoes flocculation and precipitation directly; the high-concentration oyster protein isolate forms a rough gel that has lost a large amount of water under the conventional two-stage heating (Comparative Example 3); the oyster protein isolate treated with ultra-long-term low-temperature treatment and high-temperature induced cross-linking can produce a protein gel with an intact appearance and a smooth surface; however, excessively high temperatures will damage the gel quality and reduce its appearance integrity.

[0078] 2. Gel strength

[0079] The gel strength of each embodiment was determined using a texture analyzer. Test conditions: a P / 0.5 probe was used, with a trigger force of 5g, a pressing distance of 5mm, and a speed of 2.0mm / s before, during, and after the test. Gel strength was defined as the maximum force (g) applied to a distance of 4mm.

[0080] The results are as follows Figure 2 As shown, the results indicate that the oyster protein isolate gel without high-temperature heating (Comparative Example 1) exhibited the lowest gel strength (70.20 g), while further high-temperature heating significantly enhanced the gel strength of the oyster protein isolate gel. With increasing high-temperature heating temperature, the gel strength initially increased and then decreased, reaching a maximum value of 200.89 g at 80℃, which is 2.86 times that of Comparative Example 1. Excessively high temperatures can induce excessive cross-linking of the protein, adversely affecting the gel strength.

[0081] 3. Gel hardness

[0082] Gel hardness was determined using a texture analyzer. Test conditions: TPA mode, P / 0.5 probe, trigger force 5g, compression ratio 30%, and speed 2.0mm / s before, during, and after the test. Hardness was defined as the force (g) at the maximum peak value during the first compression.

[0083] The results are as follows Figure 3 As shown, the results indicate that the oyster protein isolate gel from Comparative Example 1, which was not heated at high temperature, had the worst hardness. With further heating at higher temperatures, the hardness of all gels significantly increased, exhibiting a trend of first increasing and then decreasing. This suggests that moderate high-temperature induced cross-linking improves the hardness of the protein gel, while excessively high temperatures deteriorate the gel quality and reduce its hardness.

[0084] 4. Gel elasticity

[0085] Gel elasticity was determined using a texture analyzer. Test conditions: TPA mode, P / 0.5 probe, trigger force 5g, compression ratio 30%, and velocity of 2.0 mm / s before, during, and after the test. Elasticity was defined as the ratio of the sample recovery height detected in the second compression to the amount of compression deformation in the first compression.

[0086] The results are as follows Figure 4 As shown, the results indicate that the oyster protein isolate gel in Comparative Example 1, which was not heated at high temperature, exhibited the lowest elasticity. Further appropriate heating at high temperature improved the elasticity of the oyster protein isolate gel. With increasing temperature, the gel elasticity initially increased and then decreased. The best effect was observed at 80℃, while excessively high temperatures severely affected the gel elasticity.

[0087] 5. Gel water retention (WHC)

[0088] Weigh a certain amount of oyster protein isolate gel sample (W0) and place it in a 50 mL centrifuge tube. Centrifuge at 3000 r / min for 10 min. Wipe off the moisture on the surface of the gel and weigh it, recording its mass as W1. The formula for calculating water retention is as follows.

[0089] WHC(%) = W1 / W0 × 100%.

[0090] The results are as follows Figure 5 As shown, the results indicate that the oyster protein isolate gel in Comparative Example 1, without high-temperature heating, had the lowest water retention (65.99%). Further appropriate high-temperature heating significantly increased the water retention of the oyster protein isolate gel. With increasing temperature, the gel's water retention initially increased and then decreased, reaching a maximum at 80℃ (75.70%). These results demonstrate that further high-temperature treatment can improve the water retention of the oyster protein isolate gel, with 80℃ showing the best effect, while excessively high temperatures reduce water retention.

[0091] 6. Gel microstructure

[0092] The microstructure of the protein gel was observed using scanning electron microscopy. Before observation, the gel sample was fixed with 2.5% glutaraldehyde, dehydrated in a gradient of ethanol, freeze-dried, and sputter-coated with gold.

[0093] The results are as follows Figure 6 As shown, the protein gel prepared in Comparative Example 1 (which underwent ultra-long low-temperature coagulation treatment only at 25℃) exhibited a non-uniform microstructure with large pores. After further appropriate high-temperature heating, the microstructure of the oyster protein isolate gel gradually became more uniform, and the large pores gradually transformed into smaller pores. The oyster protein isolate gel prepared at 80℃ showed almost complete disappearance of large pores in its gel network microstructure, exhibiting the most uniform and dense network structure. However, excessively high temperatures may induce excessive cross-linking of proteins, disrupting the gel network structure.

[0094] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing oyster protein gel, characterized in that, Includes the following steps: Oyster protein isolate was obtained by alkali dissolution and acid precipitation using oyster meat as raw material; Oyster protein isolate was prepared into a protein suspension with a mass fraction of 1.5% and allowed to stand at 25±5℃ for 24 hours to coagulate. The solidified oyster protein isolate is heated at 75-80℃ for 20 minutes and then cooled to obtain the final product. The protein suspension is first homogenized at 5000-10000 rpm for 2-5 minutes, and then allowed to stand at 4°C to ensure full hydration of the protein.

2. The preparation method according to claim 1, characterized in that, The alkaline dissolution and acid precipitation process includes: mixing oyster meat with water at a mass-to-volume ratio of 1g:1~5mL, and homogenizing at a speed of 5000~10000rpm for 2~5min to obtain an oyster meat homogenate; Adjust the pH of the oyster meat homogenate to 8-12, extract for 1-4 hours, and centrifuge to obtain the alkaline extraction supernatant; Adjust the pH of the alkaline extraction supernatant to 5.5, and centrifuge to obtain the precipitate; The precipitate was redissolved in water at a ratio of 1g:1~2mL, the pH was adjusted to neutral, and the product was freeze-dried to obtain oyster protein isolate.

3. The preparation method according to claim 2, characterized in that, The centrifugation was performed at 4°C, at 10000~14000×g for 10~20 min.

4. The preparation method according to claim 1, characterized in that, The coagulated oyster protein isolate was heated at 80°C for 20 minutes.

5. Oyster protein gel obtained by the preparation method according to any one of claims 1-4.

6. The application of the oyster protein gel as described in claim 5 in the preparation of protein gel foods.

7. A protein gel food product, characterized in that, It comprises the oyster protein gel of claim 5.

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