A method for improving water holding capacity of low-salt low-phosphorus pork myofibrillar protein gel

Abstract

The application discloses a method for improving water holding capacity of low-salt and low-phosphorus pork myofibrillar protein gel, and belongs to the technical field of meat product processing technology. The method comprises the following steps: first, water bath heating and / or high-pressure homogenization pretreatment is performed on chickpea protein, and then, basic amino acids are added to obtain modified chickpea protein dispersion; the modified chickpea protein dispersion is added into a low-salt and low-phosphorus pork myofibrillar protein solution at a certain proportion, and is uniformly mixed and placed overnight to obtain a composite protein sol; and the sol is subjected to water bath cooking and cooling to obtain a composite protein gel. The modified chickpea protein dispersion obtained by adopting the basic amino acids combined with the heat and / or high-pressure homogenization pretreatment can significantly improve the water holding capacity and microstructure of the myofibrillar protein gel under the condition that the use amount of sodium chloride is reduced by 50% and no phosphates are used, and provides a new way for the development of high-quality low-salt and low-phosphorus meat products.

Description

Technical Field

[0001] This invention belongs to the field of meat processing technology, specifically relating to a method for improving the water-holding capacity of myofibrillar protein gel in low-salt, low-phosphorus pork. Background Technology

[0002] The gel properties of myofibrillar proteins play a crucial role in the quality of meat products, with water-holding capacity being one of their most important gelling characteristics. Salt (sodium chloride, NaCl) and phosphates, common additives in meat processing, can directly act on myofibrillar proteins, enhancing water retention, improving textural properties, and inhibiting lipid oxidation. However, the salt and phosphate content in meat products is generally too high, leading to food safety concerns that have attracted widespread public attention in recent years. Studies have shown that excessive salt intake increases the risk of stroke and cardiovascular disease; excessive phosphate intake affects calcium and phosphorus metabolism, causing hyperparathyroidism, metabolic bone disease, and cardiovascular calcification, increasing the risk of death by 20%–40%. Therefore, improving the gelling properties of myofibrillar proteins under low-salt and low-phosphorus conditions is an urgent problem to be solved in the production of high-quality, low-salt, and low-phosphorus meat products.

[0003] Plant proteins are widely available, inexpensive, and versatile, and are currently used as moisture retainers and texture modifiers in meat processing. Chickpea protein is an emerging representative of plant proteins, offering better economic efficiency, higher safety, and more functionality compared to common plant proteins such as soy and pea proteins, showing great promise in improving the gel quality of meat products. However, in its natural state, chickpea protein has a rigid structure, with active groups embedded within the protein molecule, making it difficult to fully realize its functions. Therefore, modification is necessary to enhance its functional properties. Currently, methods for modifying chickpea protein mainly include ultrasonic treatment and pH shifting treatment. However, the cavitation effect generated during ultrasonic treatment leads to increased protein temperature, accelerating protein denaturation. Furthermore, ultrasonic treatment generates free radicals, which may promote protein oxidation. pH shifting treatment involves extreme acidic or alkaline environments, causing pollution problems and thus not meeting the requirements of green processing. Therefore, there is an urgent need to find greener, safer, and more efficient modification methods to improve the functional properties of chickpea protein for better application in meat processing.

[0004] Small-molecule basic amino acids—arginine (Arg), lysine (Lys), and histidine (His)—can modify the structure of food proteins, thereby enhancing their functional properties. To better utilize the role of basic amino acids, it is necessary to pretreat natural chickpea protein to expose its functional groups, thus enhancing its binding with basic amino acids. Studies have shown that high-pressure homogenization can increase the flexibility of protein molecules, promote the exposure of functional groups, and has advantages such as simple process, mild processing conditions, and no harmful substances produced. In addition, heat treatment, as a universal and convenient processing method, can also stretch the protein structure to a certain extent. Based on the above research background, this invention uses chickpea protein dispersions pretreated with basic amino acids combined with heat and / or high-pressure homogenization to prepare low-salt, low-phosphorus myofibrillar protein gels, aiming to improve gel water-holding capacity and increase product yield. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention, based on fully utilizing the comprehensive modification advantages of alkaline amino acid synergistic heat treatment and / or high-pressure homogenization pretreatment on chickpea protein, improves the water-holding capacity of low-salt, low-phosphorus myofibril protein gel through the modified chickpea protein dispersion, thereby providing a novel preparation technology for healthy muscle protein gel.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following solution:

[0007] A method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel includes the following steps:

[0008] (1) Pork pretreatment;

[0009] (2) Extraction of pork myofibrillar protein;

[0010] (3) Preparation of low-salt, low-phosphorus myofibrillar protein sol;

[0011] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer to obtain chickpea protein dispersion. After stirring evenly, it was allowed to stand overnight at 4°C to fully hydrate the chickpea protein. The hydrated chickpea protein dispersion was first subjected to water bath heating treatment and / or high pressure homogenization treatment, and then basic amino acids were added to prepare modified chickpea protein dispersion. It was stored at 4°C for later use.

[0012] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The modified chickpea protein dispersion prepared in step (4) is mixed with the low-salt and low-phosphorus myofibrillar protein sol prepared in step (3) in a certain proportion to obtain chickpea protein-myofibrillar protein composite sol.

[0013] (6) Preparation of chickpea protein-myofibrillar protein composite gel: The chickpea protein-myofibrillar protein sol prepared in step (5) is boiled in a water bath and cooled to obtain chickpea protein-myofibrillar protein composite gel. The gel is the low-salt and low-phosphorus myofibrillar protein gel with improved water holding capacity.

[0014] Furthermore, the method for pre-treating pork in step (1) is as follows: take fresh pork tenderloin, remove visible fat and connective tissue, mince it into minced meat using a meat grinder, and place it at 4°C for later use; the mesh size of the meat grinder screen is 5mm.

[0015] Further, in step (2), the method for extracting pork myofibrillar protein is as follows: Take a certain amount of pork mince obtained in (1), mix it with 4 times the volume of separation buffer at pH=7.0, and homogenize it; centrifuge the mixed pork mince homogenate (2000g, 4℃, 15min), collect the precipitate, and repeat the above operation twice; during the interval between the two centrifugations, disperse it with a shear emulsifier for about 30s; redisperse the precipitate in 4 times the volume of 0.1M NaCl, and then centrifuge it (2000g, 4℃, 15min), collect the precipitate, and repeat the above operation twice; before the last centrifugation, adjust the pH of the protein suspension to 6.25 with 0.1M HCl, and filter it with 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate is myofibrillar protein. The extracted myofibrillar protein is stored at 4℃ and used within 48h.

[0016] Furthermore, the separation buffer in step (2) consists of 0.1M NaCl, 2mM MgCl2, 1mM EGTA, and 10mM NaH2PO4 / Na2HPO4.

[0017] Furthermore, the preparation method of the low-salt and low-phosphorus myofibrillar protein sol in step (3) is as follows: the pork myofibrillar protein extracted in (2) is dissolved in PIPES buffer at pH=6.25 to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%; the PIPES buffer consists of 0.3M NaCl and 50mM PIPES.

[0018] Furthermore, in step (4), the pH of the PIPES buffer is 6.25, and the components of the PIPES buffer are 0.3M NaCl and 50mM PIPES.

[0019] Furthermore, in step (4), the mass fraction of chickpea protein dispersion is 5.0%; the stirring conditions are magnetic stirring at 600 rpm at 25°C for 2 to 2.5 hours.

[0020] Furthermore, in step (4), the water bath heating conditions are: temperature 80-100℃, time 30min; the high pressure homogenization conditions are: homogenization pressure 60-100MPa, homogenization times 2-4 times; the added alkaline amino acid is L-Arg, and the addition amount is 1:100 (w / w).

[0021] Furthermore, in step (5), the mixing ratio of chickpea protein dispersion to myofibrillar protein sol is 1:4 (w / w), and the final myofibrillar protein mass fraction in the system is 4.0%.

[0022] Furthermore, in step (6), the water bath cooking conditions are: temperature 80℃, time 30min.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention provides a method for improving the water-holding capacity of low-salt, low-phosphorus muscle protein gels based on modified chickpea protein dispersions. After modification through heat and / or high-pressure homogenization pretreatment, the functional groups of chickpea protein are exposed, creating favorable conditions for subsequent binding with basic amino acids. Further treatment with basic amino acids allows the chickpea protein structure to fully unfold, thereby increasing the effective interaction with myofibrillar proteins. In addition, the modified chickpea protein makes the myofibrillar protein gel smoother, denser, and more uniform, improving the structural stability of the myofibrillar protein gel and further enhancing the performance of low-salt, low-phosphorus myofibrillar protein gels. Compared with existing technologies, the method provided by this invention can achieve low-salt and phosphorus-free production of meat protein gels while ensuring ideal water-holding capacity. It has advantages such as strong operability, high controllability, and good effects, providing technical support for the development of high-quality low-salt, low-phosphorus meat products. Attached Figure Description

[0025] Figure 1 The cooking loss of myofibrillar protein gels in the comparative examples and examples is shown in the figure (Note: the uppercase letters (AH) in the figure represent comparative example 1, comparative example 2, comparative example 3, comparative example 4, comparative example 5, example 1, example 2, and example 3, respectively; the lowercase letters (ac) in the figure indicate that there is a significant difference between different treatment groups (P<0.05). Figure 2 To compare the water retention of myofibrillar protein gels in the comparative examples and the embodiments (Note: In the figure, the uppercase letters (AH) represent comparative example 1, comparative example 2, comparative example 3, comparative example 4, comparative example 5, embodiment 1, embodiment 2, and embodiment 3, respectively; the lowercase letters (ad) in the figure indicate that there are significant differences between different treatment groups (P<0.05).

[0026] Figure 3The microstructures of myofibrillar protein gels for the examples and comparative examples are shown (Note: In the figures, capital letters (A)-(H) represent comparative examples 1, 2, 3, 4, 5, 1, 2, and 3, respectively). Detailed Implementation

[0027] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0028] In this invention, chickpea protein powder was purchased from Shaanxi Panier Biotechnology Co., Ltd., with a purity of over 80%.

[0029] L-Arg was purchased from Shanghai Yuanye Biotechnology Co., Ltd., with a purity of over 98%. The instruments and equipment involved were: a SCIENTZ-207A high-pressure homogenizer (Ningbo Xinzhi Biotechnology Co., Ltd.); an Ultra T25 high-speed homogenizer (IKA GmbH, Germany); a TU-1810 UV-Vis spectrophotometer (Beijing Purkinje General Instrument Co., Ltd.); and an FV3000 laser confocal microscope (Olympus Corporation, Japan). The testing and characterization methods involved in the embodiments and comparative examples of this invention are as follows:

[0030] Determination of cooking loss: The gel sample (weight denoted as W0) was equilibrated at room temperature for 2 hours. Residual moisture on the gel surface was wiped off with filter paper, and its weight was recorded as W1. The formula for calculating cooking loss is as follows:

[0031] Cooking loss (%) = (W0 - W1) / W0 × 100

[0032] Water retention capacity (WHC) determination: Take 2-3 g of gel sample and place it in a centrifuge tube. Centrifuge at 4℃ (10000 g, 10 min). Record the weight of the centrifuge tube (M0), the weight of the gel to the centrifuge tube before centrifugation (M1), and the weight of the gel to the centrifuge tube after centrifugation (M2). WHC is expressed as the ratio of the mass of the remaining gel after centrifugation to the mass of the gel before centrifugation. The calculation formula is as follows:

[0033] WHC(%)=(M2-M0) / (M1-M0)×100

[0034] Microstructure determination: Myofibrillar protein gel was cut into cubes approximately 1 mm thick, stained with 0.1% (w / v) rhodamine B in the dark for 30 min, and then observed under a confocal laser scanning microscopy (CLSM). The detection conditions were as follows: excitation wavelength 543 nm, emission wavelength range 550–700 nm, and objective lens magnification 20x.

[0035] Example 1

[0036] A method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel includes the following steps:

[0037] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue, mince it into minced meat using a meat grinder, and place it at 4°C for later use.

[0038] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein. The extracted myofibrillar protein was stored at 4℃ and used within 48h.

[0039] (3) Preparation of low-salt and low-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dissolved in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%.

[0040] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to form a 5.0% (w / w) chickpea protein dispersion. The dispersion was stirred evenly at room temperature and then allowed to stand overnight at 4℃ to allow the chickpea protein to fully hydrate. The hydrated chickpea protein dispersion was pretreated by heating in an 80℃ water bath for 30 min, and then L-Arg (1:100, w / w) was added to prepare the modified chickpea protein dispersion, which was stored at 4℃ for later use.

[0041] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The modified chickpea protein dispersion prepared in (4) above is mixed thoroughly with the low-salt and low-phosphorus myofibrillar protein sol prepared in (3) above at a ratio of 1:4 (w / w) to obtain chickpea protein-myofibrillar protein composite sol.

[0042] (6) Preparation of chickpea protein-myofibrillar protein composite gel: The chickpea protein-myofibrillar protein sol prepared in (5) above was boiled in a water bath at 80°C for 30 minutes and cooled to obtain chickpea protein-myofibrillar protein composite gel. The gel is the low-salt and low-phosphorus myofibrillar protein gel with improved water holding capacity.

[0043] Example 2

[0044] A method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel includes the following steps:

[0045] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue, mince it into minced meat using a meat grinder, and place it at 4°C for later use.

[0046] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein, which was stored at 4℃.

[0047] (3) Preparation of low-salt and low-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dissolved in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%.

[0048] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to form a 5.0% (w / w) chickpea protein dispersion. The dispersion was stirred evenly at room temperature and then allowed to stand overnight at 4℃ to allow the chickpea protein to fully hydrate. The hydrated chickpea protein dispersion was pretreated by high-pressure homogenization twice at 80MPa, and then L-Arg (1:100, w / w) was added to prepare the modified chickpea protein dispersion, which was stored at 4℃ for later use.

[0049] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The modified chickpea protein dispersion prepared in (4) above is mixed thoroughly with the low-salt and low-phosphorus myofibrillar protein sol prepared in (3) above at a ratio of 1:4 (w / w) to obtain chickpea protein-myofibrillar protein composite sol.

[0050] (6) Preparation of chickpea protein-myofibrillar protein composite gel: The chickpea protein-myofibrillar protein sol prepared in (5) above was boiled in a water bath at 80°C for 30 minutes and cooled to obtain chickpea protein-myofibrillar protein composite gel. The gel is the low-salt and low-phosphorus myofibrillar protein gel with improved water holding capacity.

[0051] Example 3

[0052] A method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel includes the following steps:

[0053] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue, mince it into minced meat using a meat grinder, and place it at 4°C for later use.

[0054] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (0.1M NaCl, 2mM MgCl2, 1mM EGTA, 10mM NaH2PO4 / Na2HPO4, pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein, and the extracted myofibrillar protein was stored at 4℃.

[0055] (3) Preparation of low-salt and low-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dissolved in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%.

[0056] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to form a 5.0% (w / w) chickpea protein dispersion. The dispersion was stirred evenly at room temperature and then allowed to stand overnight at 4℃ to allow the chickpea protein to fully hydrate. The hydrated chickpea protein dispersion was first heated in an 80℃ water bath for 30 min, then pretreated twice by high-pressure homogenization at 80MPa, and then L-Arg (1:100, w / w) was added to prepare the modified chickpea protein dispersion, which was stored at 4℃ for later use.

[0057] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The modified chickpea protein dispersion prepared in (4) above is mixed thoroughly with the low-salt and low-phosphorus myofibrillar protein sol prepared in (3) above at a ratio of 1:4 (w / w) to obtain chickpea protein-myofibrillar protein composite sol.

[0058] (6) Preparation of chickpea protein-myofibrillar protein composite gel: The chickpea protein-myofibrillar protein sol prepared in (5) above was boiled in a water bath at 80°C for 30 minutes and cooled to obtain chickpea protein-myofibrillar protein composite gel. The gel is the low-salt and low-phosphorus myofibrillar protein gel with improved water holding capacity.

[0059] Comparative Example 1

[0060] The preparation of traditional high-salt, high-phosphorus myofibrillar protein gel includes the following steps:

[0061] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue, mince it into minced meat using a meat grinder, and place it at 4°C for later use.

[0062] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein, which was stored at 4℃.

[0063] (3) Preparation of high-salt and high-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dissolved in high-salt PIPES buffer (0.6M NaCl, 50mM PIPES, pH=6.25), and sodium tripolyphosphate was added to make the final concentration 10mM, so as to prepare a high-salt and high-phosphorus myofibrillar protein sol with a mass fraction of 4.0%.

[0064] (4) The myofibrillar protein sol prepared in (3) above was boiled in a water bath at 80°C for 30 minutes and then cooled to obtain a high-salt, high-phosphorus myofibrillar protein gel.

[0065] Comparative Example 2

[0066] The preparation of thermally modified chickpea protein-myofibrillar protein composite gel includes the following steps:

[0067] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue from the surface, and mince it into minced meat using a meat grinder.

[0068] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (0.1M NaCl, 2mM MgCl2, 1mM EGTA, 10mM NaH2PO4 / Na2HPO4, pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein, and the extracted myofibrillar protein was stored at 4℃.

[0069] (3) Preparation of low-salt and low-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%.

[0070] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to form a 5.0% (w / w) chickpea protein dispersion. The dispersion was stirred evenly at room temperature and then allowed to stand overnight at 4℃ to allow the chickpea protein to fully hydrate. The hydrated chickpea protein dispersion was heated in an 80℃ water bath for 30 min to prepare the modified chickpea protein dispersion, which was stored at 4℃ for later use.

[0071] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The chickpea protein dispersion prepared in (4) above is mixed thoroughly with the low-salt and low-phosphorus myofibrillar protein sol prepared in (3) above at a ratio of 1:4 (w / w) to obtain chickpea protein-myofibrillar protein sol.

[0072] (6) Preparation of chickpea protein-myofibrillar protein gel: The chickpea protein-myofibrillar protein sol prepared in (5) above was boiled in a water bath at 80°C for 30 minutes and then cooled to obtain chickpea protein-myofibrillar protein composite gel.

[0073] Comparative Example 3

[0074] The preparation of high-pressure homogenized modified chickpea protein-myofibrillar protein composite gel includes the following steps:

[0075] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue from the surface, and mince it into minced meat using a meat grinder.

[0076] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (0.1M NaCl, 2mM MgCl2, 1mM EGTA, 10mM NaH2PO4 / Na2HPO4, pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein, and the extracted myofibrillar protein was stored at 4℃.

[0077] (3) Preparation of low-salt and low-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%.

[0078] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to form a 5.0% (w / w) chickpea protein dispersion. The dispersion was stirred evenly at room temperature and then allowed to stand overnight at 4℃ to allow the chickpea protein to fully hydrate. The hydrated chickpea protein dispersion was homogenized twice under high pressure at 80MPa to prepare the modified chickpea protein dispersion, which was stored at 4℃ for later use.

[0079] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The chickpea protein dispersion prepared in (4) above is mixed thoroughly with the low-salt and low-phosphorus myofibrillar protein sol prepared in (3) above at a ratio of 1:4 (w / w) to obtain chickpea protein-myofibrillar protein sol.

[0080] (6) Preparation of chickpea protein-myofibrillar protein gel: The chickpea protein-myofibrillar protein sol prepared in (5) above was boiled in a water bath at 80°C for 30 minutes and then cooled to obtain chickpea protein-myofibrillar protein composite gel.

[0081] Comparative Example 4

[0082] A heat- and high-pressure homogenized chickpea protein-myofibrillar protein complex gel, comprising the following steps:

[0083] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue from the surface, and mince it into minced meat using a meat grinder.

[0084] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (0.1M NaCl, 2mM MgCl2, 1mM EGTA, 10mM NaH2PO4 / Na2HPO4, pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein, and the extracted myofibrillar protein was stored at 4℃.

[0085] (3) Preparation of low-salt and low-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%.

[0086] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to form a 5.0% (w / w) chickpea protein dispersion. The dispersion was stirred evenly at room temperature and then allowed to stand overnight at 4℃ to allow the chickpea protein to fully hydrate. The hydrated chickpea protein dispersion was first heated in an 80℃ water bath for 30 min, and then pretreated twice by high-pressure homogenization at 80MPa to obtain the modified chickpea protein dispersion, which was stored at 4℃ for later use.

[0087] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The chickpea protein dispersion prepared in (4) above is mixed thoroughly with the low-salt and low-phosphorus myofibrillar protein sol prepared in (3) above at a ratio of 1:4 (w / w) to obtain chickpea protein-myofibrillar protein sol.

[0088] (6) Preparation of chickpea protein-myofibrillar protein gel: The chickpea protein-myofibrillar protein sol prepared in (5) above was boiled in a water bath at 80°C for 30 minutes and then cooled to obtain chickpea protein-myofibrillar protein composite gel.

[0089] Comparative Example 5

[0090] The preparation of alkaline amino acid-modified chickpea protein-myofibrillar protein composite gel includes the following steps:

[0091] (1) Pork pretreatment: Take fresh pork tenderloin, remove visible fat and connective tissue from the surface, and mince it into minced meat using a meat grinder.

[0092] (2) Extraction of pork myofibrillar protein: A certain amount of pork mince obtained in (1) was mixed with 4 times the volume of separation buffer (0.1M NaCl, 2mM MgCl2, 1mM EGTA, 10mM NaH2PO4 / Na2HPO4, pH 7.0) and homogenized. The homogenized pork mince was centrifuged (2000g, 4℃, 15min), and the precipitate was collected. The above operation was repeated twice. During the interval between the two centrifugations, the precipitate was dispersed with a shear emulsifier for about 30s. The precipitate was redispersed in 4 times the volume of 0.1M NaCl, and then centrifuged (2000g, 4℃, 15min). The precipitate was collected, and the above operation was repeated twice. Before the last centrifugation, the pH of the protein suspension was adjusted to 6.25 with 0.1M HCl, and filtered through 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The resulting precipitate was myofibrillar protein, and the extracted myofibrillar protein was stored at 4℃.

[0093] (3) Preparation of low-salt and low-phosphorus myofibrillar protein sol: The pork myofibrillar protein extracted in (2) was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%.

[0094] (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer (0.3M NaCl, 50mM PIPES, pH=6.25) to form a chickpea protein dispersion of a certain concentration. The dispersion was stirred evenly at room temperature and then allowed to stand overnight at 4℃ to allow the chickpea protein to fully hydrate. L-Arg (1:100, w / w) was added to the chickpea dispersion to prepare the modified chickpea protein dispersion, which was stored at 4℃ for later use.

[0095] (5) Preparation of chickpea protein-myofibrillar protein composite sol: The chickpea protein dispersion prepared in (4) above is mixed thoroughly with the low-salt and low-phosphorus myofibrillar protein sol prepared in (3) above at a ratio of 1:4 (w / w) to obtain chickpea protein-myofibrillar protein sol.

[0096] (6) Preparation of chickpea protein-myofibrillar protein gel: The chickpea protein-myofibrillar protein sol prepared in (5) above was boiled in a water bath at 80°C for 30 minutes and then cooled to obtain chickpea protein-myofibrillar protein composite gel.

[0097] 1. The cooking loss of meat products directly affects the product yield.

[0098] like Figure 1 As shown in Table 1, the cooking losses of Comparative Examples 2-5 were significantly higher than those of Comparative Example 1 (P<0.05), indicating that under low-salt and low-phosphorus conditions, the addition of chickpea protein dispersions modified by heat, high-pressure homogenization, heat and high-pressure homogenization, or basic amino acid modification could not achieve the ideal water-holding capacity of the myofibrillar protein gel. The cooking losses of Examples 1-3 were not significantly different from those of Comparative Example 1 (P>0.05), indicating that the chickpea protein dispersions pretreated with basic amino acids combined with heat and / or high-pressure homogenization significantly reduced the water loss of the low-salt and low-phosphorus myofibrillar protein gel, making its yield similar to that of the traditional high-salt and high-phosphorus group. The cooking losses of the myofibrillar protein gels of the comparative examples and examples are shown in Table 1 below.

[0099] Table 1. Comparison of cooking loss of myofibrillar protein gel between comparative examples and embodiments.

[0100]

[0101]

[0102] 2. Water retention is another key indicator reflecting the water-holding capacity of a gel.

[0103] from Figure 2 As shown in Table 2, the water retention of Comparative Examples 2-5 was significantly lower than that of Comparative Example 1 (P<0.05), while the water retention of Examples 1-3 was significantly higher than that of Comparative Example 1 (P<0.05). This indicates that the addition of alkaline amino acids combined with heat and / or high-pressure homogenization pretreatment of chickpea protein dispersions can significantly improve the water retention of low-salt, low-phosphorus myofibrillar protein gels. The results considering both cooking loss and water retention... Figure 1-2 As shown in Tables 1-2, the chickpea protein dispersion pretreated with alkaline amino acids combined with heat and / or high-pressure homogenization can make the water-holding capacity of the low-salt, low-phosphorus myofibrillar protein gel approach or even exceed that of the high-salt, high-phosphorus group. This may be because after alkaline amino acid pretreatment combined with heat and / or high-pressure homogenization, the functional groups of chickpea protein are fully unfolded and exposed, thereby increasing the effective interaction with myofibrillar proteins and thus improving the gel's water retention. The water retention properties of the comparative and example myofibrillar protein gels are shown in Table 2 below.

[0104] Table 2. Comparison of water retention properties of myofibrillar protein gels between comparative examples and embodiments.

[0105]

[0106] Figure 3 The microstructures of myofibrillar protein gels are shown in the examples and comparative figures. From... Figure 3 As can be seen, the gel structures of Comparative Examples 2-5 are relatively rough, containing numerous pores of varying sizes. These pores are "water channels" formed after moisture loss. In Examples 1-3, it can be observed that chickpea protein pretreated with basic amino acids and subjected to heat and / or high-pressure homogenization exhibits excellent cross-linking with the myofibrillar protein gel. The gel as a whole presents a smooth, uniform, and dense morphology, and the number and size of the "water channels" show a decreasing trend, indicating a significantly enhanced structural stability. These positive changes in microstructure effectively prevent moisture loss during cooking and centrifugation, thereby significantly improving the water-holding capacity of the low-salt, low-phosphorus myofibrillar protein gel.

[0107] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for improving the water-holding capacity of myofibrillar protein gel from low-salt, low-phosphorus pork, characterized in that... Includes the following steps: (1) Pork pretreatment; (2) Extraction of pork myofibrillar protein; (3) Preparation of low-salt, low-phosphorus myofibrillar protein sol; (4) Preparation of modified chickpea protein dispersion: Chickpea protein powder was dispersed in PIPES buffer to obtain chickpea protein dispersion. After stirring evenly, it was left to stand overnight at 4°C to allow the chickpea protein to be fully hydrated. The hydrated chickpea protein dispersion was first subjected to water bath heating treatment and / or high pressure homogenization treatment, and then basic amino acid L-Arg was added to prepare modified chickpea protein dispersion. It was stored at 4°C for later use. (5) Preparation of chickpea protein-myofibrillar protein composite sol: The modified chickpea protein dispersion prepared in step (4) is mixed with the low-salt and low-phosphorus myofibrillar protein sol prepared in step (3) in a certain proportion to obtain chickpea protein-myofibrillar protein composite sol. (6) Preparation of chickpea protein-myofibrillar protein composite gel: The chickpea protein-myofibrillar protein sol prepared in step (5) is boiled in a water bath and cooled to obtain chickpea protein-myofibrillar protein composite gel. The gel is the low-salt and low-phosphorus myofibrillar protein gel with improved water holding capacity. The preparation method of the low-salt and low-phosphorus myofibrillar protein sol in step (3) is as follows: the pork myofibrillar protein extracted in (2) is dissolved in PIPES buffer at pH = 6.25 to prepare a low-salt and low-phosphorus myofibrillar protein sol with a mass fraction of 5.0%; the PIPES buffer consists of 0.3 M NaCl and 50 mM PIPES. In step (4), the pH of the PIPES buffer is 6.25, and the components of the PIPES buffer are 0.3 M NaCl and 50 mM PIPES. In step (4), the water bath heating conditions are: temperature 80~100 ℃, time 30 min; the high pressure homogenization conditions are: homogenization pressure 60~100 MPa, homogenization times 2~4 times; the addition amount of alkaline amino acid L-Arg and the mass ratio of chickpea protein dispersion is 1:

100.

2. The method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel according to claim 1, characterized in that: The method for pre-treating pork in step (1) is as follows: take fresh pork tenderloin, remove visible fat and connective tissue, mince it into minced meat using a meat grinder, and place it at 4°C for later use; the mesh size of the meat grinder screen is 5 mm.

3. The method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel according to claim 1, characterized in that: In step (2), the method for extracting pork myofibrillar protein is as follows: Take a certain amount of pork mince obtained in (1), mix it with 4 times the volume of separation buffer at pH=7.0, and homogenize it; centrifuge the mixed pork mince homogenate, collect the precipitate, and repeat the above operation twice; during the interval between the two centrifugations, disperse it with a shear emulsifier for 30 s; redisperse the precipitate in 4 times the volume of 0.1M NaCl, then centrifuge and collect the precipitate, and repeat the above operation twice; before the last centrifugation, adjust the pH of the protein suspension to 6.25 with 0.1M HCl, and filter it with 4 layers of gauze to remove the connective tissue visible to the naked eye in the protein. The precipitate obtained is myofibrillar protein. The extracted myofibrillar protein is stored at 4℃ and used within 48 h.

4. The method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel according to claim 3, characterized in that: In step (2), the separation buffer consists of 0.1 M NaCl, 2 mM MgCl2, 1 mM EGTA, and 10 mM NaH2PO4 / Na2HPO4.

5. The method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel according to claim 1, characterized in that: In step (4), the mass fraction of chickpea protein dispersion is 5.0%; the stirring conditions are magnetic stirring at 600 rpm at 25°C for 2~2.5 h.

6. The method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel according to claim 1, characterized in that: In step (5), the mass ratio of chickpea protein dispersion to myofibrillar protein sol is 1:4, and the final myofibrillar protein mass fraction in the system is 4.0%.

7. The method for improving the water-holding capacity of low-salt, low-phosphorus pork myofibrillar protein gel according to claim 1, characterized in that: In step (6), the water bath cooking conditions are: temperature 80℃, time 30 min.

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