A method for efficiently extracting PSE meat protein based on alkaline pH regulation

Abstract

The application discloses a PSE meat protein efficient extraction method based on alkaline pH regulation, and belongs to the technical field of meat protein extraction. The steps are as follows: after PSE meat is uniformly homogenized, pre-cooled deionized water is added at 1:9 (w / v), the pH is adjusted to 11.5-13.0, stirring extraction is carried out for 5 min, and the supernatant is collected by centrifugation; the pH of the supernatant is adjusted back to 5.5, and after standing and precipitating, centrifugation is carried out, and the precipitate is collected; the precipitate is freeze-dried, and PSE meat myofibrillar protein is obtained. The application aims at the problems of PSE meat protein denaturation and functional property deterioration, realizes efficient dissolution of protein through alkaline pH regulation, has high protein purity and retains complete salt-soluble protein, and provides a simple and efficient solution for high-value utilization of PSE meat.

Description

Technical Field

[0001] This invention belongs to the field of meat protein extraction technology, specifically relating to a highly efficient PSE meat protein extraction method based on alkaline pH control. Background Technology

[0002] PSE meat (Pale, Soft, Exudative Meat) refers to substandard meat products that are pale in color, soft in texture, and exude excessive juices. Its formation is caused by the synergistic effect of a rapid drop in pH and high temperature after slaughter, leading to the denaturation and aggregation of myofibril proteins. Although PSE meat does not pose a safety risk for consumption, its poor water retention and weak gelling ability result in significantly lower processing characteristics and commercial value compared to normal meat products, causing substantial economic losses to the meat industry. While the industry has attempted to curb the production of PSE meat through genetic selection and pre-slaughter management optimization, it has not yet been completely eliminated. Therefore, exploring technological pathways for the high-value utilization of PSE meat has become a crucial issue for promoting the sustainable development of the meat industry.

[0003] pH adjustment is a classic protein separation technique that utilizes the physicochemical property that proteins have the lowest solubility at their isoelectric point, while their solubility significantly increases under pH conditions deviating from the isoelectric point. Protein dissolution is achieved through extreme pH environments, followed by centrifugation to remove impurities and then adjusting the pH back to the isoelectric point to complete protein precipitation and separation. This technique is simple to operate, low in cost, and yields high protein activity retention, and has been successfully applied to protein extraction from aquatic products such as tilapia and silver carp, as well as turkey by-products. Existing research indicates that pH adjustment can be used to extract protein from low-quality meat raw materials, but different pH conditions have significantly different effects on protein extraction efficiency and retention of functional properties. Acidic extraction, while resulting in less protein denaturation, leads to a lower extraction rate; alkaline extraction, while yielding a higher rate, easily causes excessive protein denaturation, affecting its functional properties.

[0004] Current protein extraction methods for PSE meat still face the technical challenge of balancing extraction efficiency with the preservation of protein functional properties. Existing pH adjustment methods lack specific optimization for PSE meat, a denatured protein raw material, and have not systematically studied the effects of different pH conditions on the dissolution behavior and component retention of PSE meat proteins. This makes it difficult to effectively retain functional components such as salt-soluble myofibrillar proteins while ensuring high extraction rates. Therefore, developing an extraction method specifically tailored to the characteristics of PSE meat that can achieve efficient extraction while maximizing the preservation of protein functional properties has significant practical implications and application value. Summary of the Invention

[0005] The problem to be solved by the present invention is to overcome the technical defects of the prior art in which it is difficult to balance the extraction efficiency and retention of functional properties of PSE meat protein, and to provide a PSE meat protein extraction method that is simple to operate, has high extraction efficiency and can retain salt-soluble protein to the maximum extent.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solution: a method for efficient extraction of PSE meat protein based on alkaline pH control, wherein the material-to-liquid ratio of the method is 1:8-1:10 (w / v); the extraction pH is 11.5-13.0; the extraction time is 3-10 min; the precipitation pH is 5.0-6.0; the centrifugation speed is 8000-12000 r / min; and the drying method is freeze drying.

[0007] A highly efficient method for extracting PSE meat protein based on alkaline pH control includes the following steps: (1) After homogenizing the PSE meat, add pre-cooled deionized water at a material-to-liquid ratio of 1:8-1:10 (w / v) and stir until homogenized; (2) Adjust the pH of the system to 11.5-13.0, stir and extract for 3-10 min, and collect the supernatant by centrifugation; (3) Adjust the pH of the supernatant to 5.0-6.0, let it stand to precipitate, then centrifuge and collect the precipitate; (4) Dry the precipitate to obtain PSE muscle myofibril protein.

[0008] The present invention also includes the following features: The PSE meat in (1) is prepared by the following method: take the longissimus dorsi muscle of pig, soak it in 0.1% liquid preservative MB-1 solution for 5-10 s, vacuum package it and then treat it in a water bath at 35℃ for 7-8 h, and freeze it at -40℃ for later use.

[0009] The homogenization in (1) is carried out at 4℃ and stirred at 10000-15000 r / min for 2-3 min.

[0010] The pH value extracted in (2) is further preferably 12.0.

[0011] The stirring extraction time in (2) is further preferably 5 min.

[0012] The centrifugation conditions in (2) are 4℃, 8000-12000 r / min for 10-20 min, and more preferably 10000 r / min for 15 min.

[0013] In step (3), the pH value for the pullback is further preferably 5.5.

[0014] The centrifugation conditions in (3) are 4℃, 8000-12000 r / min for 10-20 min, and more preferably 8000 r / min for 15 min.

[0015] The drying in (4) is freeze drying, and the freeze drying conditions are -80℃ and 0.1 mbar vacuum pressure for 48 hours.

[0016] The present invention has the following advantages: (1) The present invention extracts the protein by alkaline pH regulation, and the salt-soluble myofibrillar protein content in the obtained protein reaches 72%-76%, which is significantly higher than the 64%-65% of PSE raw material. It effectively preserves the functional components of the protein and lays a high-quality raw material foundation for subsequent protein modification and product development. (2) This invention systematically optimizes the alkaline pH-controlled extraction process for the first time, targeting the denaturation characteristics of PSE meat protein. Under pH 11.5-13.0 conditions, the protein yield can reach more than 70%, which is significantly higher than the approximately 65% ​​of the traditional acid extraction method. This achieves efficient recovery of PSE meat protein and provides an effective technical path for the high-value utilization of low-value meat. (3) The method of the present invention is simple to operate and low in cost. The entire process is carried out at a low temperature of 4℃, which minimizes the denaturation of protein during the extraction process. At the same time, the freeze-drying technology ensures the storage stability of the protein product, making it suitable for industrial production. (4) This invention successfully transforms PSE meat, a low-value by-product, into a high-value protein raw material, solving the long-standing problem of resource waste in the meat processing industry and achieving significant economic and social benefits. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 This is a comparison chart of protein yields in Examples 1-2 and Comparative Examples 1-2 of the present invention. The chart shows that the protein yields of Example 1 (pH 12.0) and Example 2 (pH 13.0) were 73.77% and 70.22%, respectively, significantly higher than those of Comparative Example 1 (pH 3.0) (66.13%) and Comparative Example 2 (pH 2.0) (65.32%). Figure 2 This is a comparison chart of the salt-soluble protein content of Examples 1-2 and Comparative Examples 1-3 of the present invention. The chart shows that the salt-soluble protein content in the proteins obtained in Examples 1 and 2 is 75.19% and 74.58%, respectively, which is significantly higher than that in Comparative Example 1 (67.54%), Comparative Example 2 (66.95%) and Comparative Example 3 (64.65%). Detailed Implementation

[0018] The PSE meat used in the examples was prepared by the following method: the longissimus dorsi muscle of pig was taken, soaked in 0.1% liquid preservative MB-1 solution for 5 seconds, vacuum packaged, and then treated in a water bath at 35℃ for 7 hours, and frozen at -40℃ for later use. Example

[0019] A highly efficient extraction method for PSE meat protein based on alkaline pH regulation, the specific steps of which are as follows: Step 1: Thaw the PSE meat in a 4℃ refrigerator for 12 hours. Take 30 g of meat sample and add 270 mL of pre-cooled deionized water at a material-to-liquid ratio of 1:9 (w / v). Stir at 12000 r / min for 2 minutes at 4℃ to obtain PSE meat homogenate.

[0020] Step 2: Adjust the pH of the system to 12.0 with 1 mol / L NaOH, stir and extract for 5 min at 4℃, then centrifuge at 10000 r / min for 15 min at 4℃ and collect the supernatant.

[0021] Step 3: Adjust the pH of the supernatant to 5.5 with 1 mol / L HCl, allow it to stand and precipitate, then centrifuge at 4℃ and 8000 r / min for 15 min and collect the precipitate.

[0022] Step 4: Freeze-dry the obtained precipitate at -80℃ and 0.1 mbar vacuum pressure for 48 h, grind and sieve to obtain PSE muscle myofibril protein powder.

[0023] In this example, the protein yield was 73.77%, and the salt-soluble protein content of the obtained protein was 75.19%. Example

[0024] This embodiment is basically the same as the method described in Embodiment 1, except that the pH is adjusted to 13.0 in step 2.

[0025] In this example, the protein yield was 70.22%, and the salt-soluble protein content of the obtained protein was 74.58%.

[0026] Comparative Example 1: Step 1: Thaw the PSE meat in a 4℃ refrigerator for 12 hours. Take 30 g of meat sample and add 270 mL of pre-cooled deionized water at a material-to-liquid ratio of 1:9 (w / v). Stir at 12000 r / min for 2 minutes at 4℃ to obtain PSE meat homogenate. Step 2: Adjust the pH of the system to 3.0 with 1 mol / L HCl, stir and extract for 5 min at 4℃, then centrifuge at 10000 r / min for 15 min at 4℃ and collect the supernatant; Step 3: Adjust the pH of the supernatant to 5.5 with 1 mol / L HCl, allow it to stand and precipitate, then centrifuge at 4℃ and 8000 r / min for 15 min and collect the precipitate. Step 4: Freeze-dry the obtained precipitate at -80℃ and 0.1 mbar vacuum pressure for 48 h, grind and sieve to obtain PSE muscle myofibril protein powder; The protein yield in this comparative example was 66.13%, and the salt-soluble protein content of the obtained protein was 67.54%.

[0027] Comparative Example 2: The method described in this comparative example is basically the same as that in comparative example one, except that the pH is adjusted to 2.0 in step two for extraction. The protein yield in this comparative example was 65.32%, and the salt-soluble protein content of the obtained protein was 66.95%.

[0028] Comparative Example 3: Step 1: Thaw the PSE meat in a 4℃ refrigerator for 12 hours. Take 30 g of meat sample and add 270 mL of pre-cooled deionized water at a material-to-liquid ratio of 1:9 (w / v). Stir at 12000 r / min for 2 minutes at 4℃ to obtain PSE meat homogenate. Step 2: Centrifuge the PSE meat homogenate obtained in Step 1 at 4℃ and 10000 r / min for 15 min and collect the precipitate; Step 3: Freeze-dry the obtained precipitate at -80℃ and 0.1 mbar vacuum pressure for 48 h, grind and sieve to obtain PSE meat raw material freeze-dried powder; The salt-soluble protein content in this comparative example is 64.65%.

[0029] The protein samples prepared in Examples 1-2 and Comparative Examples 1-3 were subjected to performance tests, as detailed below: 1. Protein yield determination The crude protein content of PSE meat raw materials and isolated protein was determined by the Kjeldahl method, and the protein yield was calculated according to the following formula: Protein yield (%) = (Crude protein content of isolated protein / Crude protein content of PSE meat) × 100 like Figure 1As shown, the protein yields of Example 1 (pH 12.0) and Example 2 (pH 13.0) were 73.77% and 70.22%, respectively, significantly higher than those of Comparative Example 1 (pH 3.0) (66.13%) and Comparative Example 2 (pH 2.0) (65.32%). This indicates that alkaline pH regulation can significantly improve the extraction efficiency of PSE meat protein. 2. Determination of salt-soluble protein content Take 5 g of sample and dissolve it in high-salt phosphate buffer (0.6 mol / L KCl, 0.02 mol / L NaH2PO4, 0.02 mol / L Na2HPO4, pH 7.0), extract at 4℃ for 20 h, centrifuge at 10000 r / min for 15 min, and take the supernatant to determine the protein content by Kjeldahl method; like Figure 2 As shown, the salt-soluble protein contents in the proteins obtained in Examples 1 and 2 were 75.19% and 74.58%, respectively, which were significantly higher than those in Comparative Example 1 (67.54%), Comparative Example 2 (66.95%), and Comparative Example 3 (64.65%). This indicates that alkaline pH-controlled extraction can effectively enrich salt-soluble myofibrillar proteins and preserve their functional properties.

Claims

1. A method for efficient extraction of PSE meat protein based on alkaline pH regulation, characterized in that, Includes the following steps: S1: After homogenizing the PSE meat, add pre-cooled deionized water at a material-to-liquid ratio of 1:8-1:10 (w / v) and stir well; S2: Adjust the pH of the system to 11.5-13.0, stir and extract for 3-10 min, then centrifuge and collect the supernatant; S3: Adjust the pH of the supernatant to 5.0-6.0, allow it to settle, centrifuge, and collect the precipitate; S4: Dry the precipitate to obtain PSE muscle myofibrillar protein.

2. The extraction method according to claim 1, characterized in that, The PSE meat in S1 is prepared by the following method: take the longissimus dorsi muscle of pig, soak it in 0.1% liquid preservative MB-1 solution for 5-10 s, vacuum package it, and then treat it in a water bath at 35℃ for 7-8 h, and freeze it at -40℃ for later use.

3. The extraction method according to claim 1, characterized in that, The homogenization in S1 is carried out at 4℃ and stirred at 10000-15000 r / min for 2-3 min.

4. The extraction method according to claim 1, characterized in that, The centrifugation conditions in S2 are: 4℃, 8000-12000 r / min for 10-20 min.

5. The extraction method according to claim 1, characterized in that, The centrifugation conditions in S3 are: 4℃, 8000-12000 r / min for 10-20 min.

6. The extraction method according to claim 1, characterized in that, The drying process in S4 is freeze drying.

7. The extraction method according to claim 6, characterized in that, The freeze-drying conditions are: -80℃, 0.1mbar vacuum pressure for 48 h.

Images