A method for preparing meat emulsion with enzymatic fish skin peptide as emulsifier

Abstract

The application belongs to the technical field of biological enzymolysis, and particularly relates to a kind of minced meat preparation method with enzymatic fish skin peptide as emulsifier.The preparation method comprises the following steps: S1, fermentation: the fish skin is broken into small pieces, low-temperature colloid mill is used for breaking, stirring is uniformly carried out, and saccharomyces cerevisiae is inoculated to carry out fermentation;S2, enzymolysis: the material obtained in step S1 is sequentially added into collagenase, flavour protease-amino peptidase and TG enzyme to carry out enzymolysis, and enzymatic fish skin peptide is obtained;S3, step-by-step chopping: the enzymatic fish skin peptide obtained in step S2 is added into meat matrix to carry out step-by-step chopping, and uniformly emulsified minced meat is obtained.The application provides a kind of minced meat preparation method with enzymatic fish skin peptide as emulsifier, low-value fish skin processing by-product is modified by specific biological enzymolysis technology, and is converted into functional protein peptide (fish skin enzymolysis) with efficient emulsifying property and gel enhancement, so as to be used for the preparation of minced meat.

Description

Technical Field

[0001] This invention belongs to the field of bio-enzymatic hydrolysis technology, specifically relating to a method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier. Background Technology

[0002] The core quality of minced meat products (such as sausages, meatballs, and pet meat pellets) lies in their emulsification stability and textural properties. Traditional processes typically rely on chemically synthesized emulsifiers (such as polyglycerol fatty acid esters), phosphates, or plant proteins (such as soy protein isolate) to achieve emulsification and water retention. However, existing technologies have the following significant shortcomings:

[0003] (1) Safety and applicability defects: Long-term intake of chemically synthesized emulsifiers (such as propylene glycol fatty acid esters) may increase the metabolic burden on animal livers, which is inconsistent with the consumption trend of "natural and clean labels"; Although phosphates can improve water retention, excessive addition can lead to deterioration of meat flavor and may cause urinary system problems in pets; Soy protein isolate has allergenicity (containing soy globulin), which limits its application in high-end pet food;

[0004] (2) Existing limitations of fish skin peptide application: Fish skin, a by-product of aquatic product processing, is rich in collagen and is an ideal raw material for preparing natural emulsified peptides. However, existing fish skin peptide preparation technology has obvious shortcomings.

[0005] (3) Pretreatment relies on chemical degreasing (such as soaking in sodium hydroxide) or high-temperature cooking, which leads to the destruction of collagen structure and low activity of subsequent enzymatic hydrolysis products;

[0006] (4) The enzymatic hydrolysis process uses a single protease (such as alkaline protease), and the peptide molecular weight is dispersed, making it difficult to balance emulsifying activity and bitterness.

[0007] (5) Lack of synergistic design with the meat paste matrix, poor emulsification stability when added alone, and inability to effectively improve the strength of the meat paste gel;

[0008] (6) Low process efficiency: Existing technologies require multiple purification steps (such as desalting and deodorizing), the utilization rate of fish skin raw materials is only 5-10%, the production cost is high, and it is difficult to apply industrially.

[0009] In summary, maintaining a stable fat-water system (emulsification stability) is a core technological challenge in the production of emulsified meat products such as wet pet food, sausages, and meatballs. Poor emulsification leads to the separation of oil, water, and fat during cooking, reducing yield and resulting in a loose product structure and a coarse texture. Traditional processes often use chemically synthesized emulsifiers, phosphates, or large amounts of starch to improve stability, but this contradicts the consumer trend towards "clean" products. Therefore, developing efficient and natural alternatives is an important research direction for the industry.

[0010] Existing technologies either fail to fully exploit the intrinsic functional value of fish skin (e.g., through simple mixing) or rely on non-natural, allergenic, or costly exogenous additives, thus failing to simultaneously meet the multiple objectives of high-value utilization of byproducts, clean labeling, and improved product natural quality. Therefore, the industry urgently needs an innovative technology that can transform this inexpensive byproduct into a highly efficient, natural, and nutritious functional ingredient, and precisely apply it to pet food systems. Summary of the Invention

[0011] This invention addresses the shortcomings of existing technologies, such as insufficient safety of chemical emulsifiers, inefficient fish skin peptide preparation processes, and poor emulsification and texture improvement effects in meat paste. It provides a method for preparing meat paste using enzymatically hydrolyzed fish skin peptides as an emulsifier. This method transforms low-value fish skin processing byproducts into functional protein peptides (fish skin hydrolysate) with highly efficient emulsifying and gel-enhancing properties through specific enzymatic hydrolysis technology, thus enabling their use in meat paste preparation.

[0012] The specific technical solution is as follows:

[0013] A method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier includes the following steps:

[0014] S1. Fermentation: The fish skin is crushed into small pieces, crushed using a low-temperature colloid mill, stirred evenly, and inoculated with brewing yeast for fermentation.

[0015] S2. Enzymatic hydrolysis: The material obtained in step S1 is successively added to collagenase, flavor protease-aminopeptidase and TG enzyme for enzymatic hydrolysis to obtain enzymatically hydrolyzed fish skin peptides.

[0016] S3. Step-by-step chopping and mixing: Add the enzymatically hydrolyzed fish skin peptides obtained in step S2 to the meat matrix and chop and mix in steps to obtain a uniformly emulsified meat paste.

[0017] This invention provides a natural emulsifier preparation process based on fish skin by-products, which does not require chemical additives and achieves the dual goals of "high-value utilization of waste" and "clean labeling".

[0018] By combining targeted enzymatic hydrolysis and fermentation, the problems of "strong bitterness, low emulsifying activity, and dispersed molecular weight" of fish skin peptides are solved.

[0019] Optimize the compatibility process between fish skin peptides and minced meat to improve the emulsification stability, water retention and gel strength of minced meat, and meet the production requirements of high-quality minced meat products (especially pet food).

[0020] Further, in step S1, after thawing the fish skin, pre-treatment is performed. The fish skin is rinsed 2-5 times with running water to remove surface blood and impurities. It is then crushed into small pieces of 2-3 cm using a crusher, without deep degreasing, to provide a small amount of fat as a carbon source for fermentation microorganisms. The mixture is then crushed and stirred evenly using a low-temperature colloid mill at a speed of 3000-5000 r / min for 2-5 minutes, controlling the fish skin particle size to 100-200 μm. This preserves the basic structure of collagen fibers while facilitating microbial attachment. The solid-liquid ratio is (1:5)-(1:10) (g / mL), with water as the solvent. Food-grade Saccharomyces cerevisiae is inoculated for fermentation at 2-5% (v / w) of the dry weight of the fish skin. Saccharomyces cerevisiae metabolizes and decomposes trimethylamine, aldehydes, and other fishy-smelling substances, while producing ester flavor compounds to mask bitterness. Fermentation is carried out at a constant temperature of 25-30℃, with an initial pH of... 5.0-7.0, shaker speed 100-200r / min, fermentation time 36-72h, to achieve deodorization and substrate softening.

[0021] Furthermore, after fermentation in step S1, the trimethylamine content in the system is ≤0.015 mg / kg.

[0022] Furthermore, in step S2, a three-stage directional enzymatic hydrolysis is adopted: collagenase → flavor protease → aminopeptidase → TG enzyme (endo-exo-modification).

[0023] Furthermore, in step S2, primary endopeptidation is performed: Clostridium collagenase (enzyme activity 2000 U / g) is selected to specifically cleave the glycine-proline-hydroxyproline repeat sequence unique to collagen. The amount of enzyme added is 0.3-0.5% of the dry weight of fish skin. Enzymatic hydrolysis is carried out at pH 5.0-7.0 (no acid-base adjustment required) and 30-50℃ for 1-3 hours, so that more than 80% of the collagen is broken down into 3-5kDa intermediate peptides. Compared with alkaline proteases, the proportion of peptides in the target molecular weight range is increased by 50%, and the polydispersity index is reduced to below 1.25.

[0024] Further, in step S2, the secondary exonuclease modification is performed as follows: the enzymatic hydrolysis conditions of the flavor protease-aminopeptidase are: hydrolysis temperature 30-40℃, hydrolysis time 1-3h, total enzyme addition is 0.5-0.7% of the dry weight of fish skin, and the mass ratio of flavor protease (exonuclease, enzyme activity 1500U / g) and aminopeptidase (terminal peptidase, enzyme activity 1000U / g) is (1:3)-(3:1). The flavor protease removes the hydrophobic amino acids (leucine, isoleucine) at the end of the peptide chain, reducing the bitterness value to ≤1.0, and retaining N-terminal glycine to enhance amphiphilicity (oil-water interfacial tension reduced to ≤22mN / m).

[0025] Furthermore, in step S2, tertiary TG enzyme cross-linking is performed: microbial transglutaminase (TG enzyme, enzyme activity 100 U / g) is introduced. The enzymatic hydrolysis conditions of the TG enzyme are: hydrolysis temperature 40-50℃, hydrolysis time 30-50min, and enzyme dosage is 0.4-0.6% of the dry weight of fish skin, so that the 3-5kDa peptides are cross-linked into a 1-3kDa "linear-branched" complex structure, thereby improving antioxidant properties and emulsification stability.

[0026] Furthermore, the molecular weight of the enzymatically hydrolyzed fish skin peptides finally obtained in step S2 is concentrated in the range of 1000-3000 Da (accounting for ≥80%).

[0027] Furthermore, in step S3, the raw material composition of the minced meat includes enzymatically hydrolyzed fish skin peptides and meat matrix. The amount of enzymatically hydrolyzed fish skin peptides added is 1.5-3.0% of the weight of the meat matrix, and the meat matrix is ​​selected from one or more of poultry meat, livestock meat, and fish meat.

[0028] Furthermore, the chopping process in step S3 adopts a step-by-step chopping process. In the first step, the meat matrix (such as chicken breast or pork back fat) is mixed and chopped with a mixture of chicken carcass and chicken bones. The weight of the mixture of chicken carcass and chicken bones is 5-10% of the meat matrix. The chopping speed is 1500-2000 r / min and the time is 2-3 min. In the second step, enzymatically hydrolyzed fish skin peptides and auxiliary materials (salt ≤1%, ice water) are added and chopping is continued. The chopping speed is 2000-2500 r / min and the time is 3-5 min. The final meat paste emulsion particle size is 30-50 mesh (90% sieved).

[0029] Furthermore, it also includes step S4: packaging, sealing and sterilizing the uniformly emulsified meat paste obtained in step S3. The sterilization conditions are all-water sterilization, which is carried out at 121°C and 0.18 MPa for 30-50 minutes.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) This invention provides a novel production method that uses bio-enzymatic hydrolysis technology to convert fish skin into functional protein peptides and applies them as emulsifiers and gel enhancers to mixed meat pastes such as chicken and fish skin, so as to enhance the quality of meat-fish skin mixed meat pastes and improve the quality of pet food. Its core is to convert fish skin by-products into functional ingredients rich in small molecule peptides through bio-enzymatic hydrolysis technology and then accurately add them to the meat matrix, thereby significantly improving the emulsification stability, texture characteristics and nutritional value of the product without relying on chemical additives.

[0032] (2) The emulsification mechanism of the present invention is as follows: During the chopping process, the hydrophobic ends of the peptides adsorb onto the surface of fat globules, while the hydrophilic ends extend into the aqueous phase, forming a stable protein peptide film on the surface of the fat globules, preventing the fat globules from aggregating and floating, thereby achieving excellent emulsification stability. Gel enhancement mechanism: During the heating process, these peptides can interact with the myofibrillar proteins (such as myosin) of the meat itself, filling the protein gel network structure, enhancing the density and water retention of the network, thereby improving the elasticity, firmness and juiciness of the product.

[0033] (3) This invention transforms cheap fish skin into high-end ingredients through high-value technology, realizing the high-value utilization of fish skin waste, improving the palatability and nutritional value of pet food, replacing chemically synthesized emulsifiers, and providing a safe and natural emulsification stabilization solution to meet the market demand for "clean label" and healthy formula. While reducing costs, it greatly enhances the technological content and market value of the product.

[0034] (4) Safety and naturalness: No chemically synthesized emulsifiers, phosphates or soy protein are required throughout the process. The enzymatically hydrolyzed fish skin peptides are of natural origin, non-allergenic, and meet the requirements of the clean label, making them especially suitable for pet food.

[0035] High activity and integrated functions: Enzymatically hydrolyzed fish skin peptides have high emulsifying activity, strong antioxidant properties and low bitterness. The emulsification stratification rate is low after 5 hours, which solves the problem of the single function of traditional fish skin peptides.

[0036] The quality of minced meat is significantly improved: after the addition, the water holding capacity of minced meat increases, the cooking loss rate decreases, the gel strength is enhanced, and there is no obvious oil separation after 3 freeze-thaw cycles. Its texture and stability are superior to those of the chemical emulsifier group.

[0037] High-value raw materials and low cost: Increased utilization of fish skin, reduced use of exogenous enzymes through fermentation-enzymatic hydrolysis, lower process costs, and suitability for industrial production. Detailed Implementation

[0038] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0039] In the specific embodiments and comparative examples: the fish skin raw material is 100g of tuna skin; the fermentation strain is food-grade brewing yeast (Saccharomyces cerevisiae) with a viable count ≥1×10⁻⁶. 9CFU / g, purchased from Hubei Angel Yeast Co., Ltd.; the Clostridium collagenase (enzyme activity 2000 U / g), flavor protease (exonuclease, enzyme activity 1500 U / g), aminopeptidase (terminal peptidase, enzyme activity 1000 U / g), and microbial transglutaminase (TG enzyme, enzyme activity 100 U / g) used were all food grade and purchased from Nanning Pangbo Biotechnology Co., Ltd.

[0040] Example 1

[0041] A method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier includes the following steps:

[0042] S1. Fish skin pretreatment:

[0043] Fish skin, a byproduct of aquatic product processing, is subjected to the following treatment:

[0044] Cleaning and crushing: After thawing the fish skin, trim it and rinse it twice with running water to remove blood and impurities. Crush it into small pieces of 2-3cm using a crusher, then crush and mix it evenly with a low-temperature colloid mill (3000r / min, 5min), controlling the particle size to 100-200μm. Adjust the solid-liquid ratio to 1:8 (g / mL) and add 800mL of water as a solvent. No deep defatting is required; retain a small amount of fat as a carbon source for subsequent fermentation.

[0045] S2. Fish skin fermentation to remove fishy smell:

[0046] The fish skin homogenate obtained in step S1 was inoculated with food-grade brewing yeast for fermentation. The inoculation amount was 5% (v / w) of the dry weight of the fish skin. Fermentation was carried out at 30℃, initial pH 7.0 (natural pH of the fish skin substrate), and shaking speed of 150 r / min for 48 h to achieve deodorization (trimethylamine content reduced to ≤0.015 mg / kg) and substrate softening.

[0047] S3. Targeted enzymatic hydrolysis of fish skin peptides (tertiary enzymatic hydrolysis):

[0048] The material obtained in step S2 was successively added to collagenase, flavor protease-aminopeptidase and TG enzyme for enzymatic hydrolysis to obtain enzymatically hydrolyzed fish skin peptides.

[0049] The enzymatic hydrolysis conditions were as follows: collagenase hydrolysis: pH 7.0, hydrolysis temperature 40℃, hydrolysis time 2h, and enzyme dosage was 0.4% of the dry weight of the fish skin;

[0050] The enzymatic hydrolysis conditions for flavor protease-aminopeptidase are: hydrolysis temperature 37℃, hydrolysis time 1h, total enzyme addition of 0.5% of the dry weight of fish skin, and mass ratio of flavor protease to aminopeptidase of 3:1.

[0051] TG enzyme modification: enzymatic hydrolysis temperature 45℃, enzymatic hydrolysis time 30min, enzyme dosage is 0.6% of the dry weight of fish skin;

[0052] S4. Step-by-step chopping and mixing: Add the enzymatically hydrolyzed fish skin peptides obtained in step S3 to the meat matrix and chop and mix in steps to obtain a uniformly emulsified meat paste.

[0053] The amount of enzymatically hydrolyzed fish skin peptide added is 2.0% of the weight of the meat matrix, which is selected from chicken, duck, beef, and fish.

[0054] The chopping process is carried out in steps. The first step is to chop the mixture of meat matrix and chicken carcass and bones, wherein the weight of the mixture of chicken carcass and bones is 8% of the meat matrix, at a speed of 1500 r / min for 3 min. The second step is to add enzymatically hydrolyzed fish skin peptides at a speed of 2000 r / min for 5 min. The final meat paste emulsion particle size is 30 mesh (90% sieved).

[0055] S5. The uniformly emulsified meat paste obtained in step S4 is packaged, sealed, and sterilized. The sterilization conditions are all-water sterilization, which is carried out at 121℃ and 0.18 MPa for 30 minutes.

[0056] Example 2

[0057] A method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier includes the following steps:

[0058] Referring to Example 1, the difference from Example 1 is that in step S1: the colloid mill is used to crush and stir for 2 minutes, and the solid-liquid ratio is adjusted to 1:5 (g / mL).

[0059] In step S2: the inoculation amount of food-grade brewing yeast is 2% (v / w) of the dry weight of fish skin, the temperature is 25℃, the initial pH is 5.0, the shaking speed is 100r / min, and the fermentation time is 36h.

[0060] In step S3: the enzymatic hydrolysis conditions for collagenase are: pH 5.0, temperature 30℃, time 1 h, and enzyme dosage of 0.3% of the dry weight of fish skin; the enzymatic hydrolysis conditions for flavor protease-aminopeptidase are: temperature 30℃, time 2 h, enzyme dosage of 0.6% of the dry weight of fish skin, and a mass ratio of flavor protease to aminopeptidase of 1:3; the enzymatic hydrolysis conditions for TG enzyme are: temperature 40℃, time 40 min, and enzyme dosage of 0.4% of the dry weight of fish skin.

[0061] In step S4: the weight of chicken carcass and bones added is 5% of the meat matrix, the rotation speed is 1800 r / min, and the time is 2.5 min. In the second step, enzymatically hydrolyzed fish skin peptides are added, the rotation speed is 2300 r / min, and the time is 4 min. The final meat paste emulsion particle size is 40 mesh.

[0062] Other technical features are the same as in Example 1.

[0063] Example 3

[0064] A method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier includes the following steps:

[0065] Referring to Example 1, the difference from Example 1 is that in step S1: the colloid mill is used to crush and stir for 4 minutes, and the solid-liquid ratio is adjusted to 1:10 (g / mL).

[0066] In step S2: the inoculation amount of food-grade brewing yeast is 4% (v / w) of the dry weight of fish skin, the temperature is 28℃, the initial pH is 6.0, the shaking speed is 200r / min, and the fermentation time is 72h;

[0067] In step S3: the enzymatic hydrolysis conditions for collagenase are: pH 6.0, temperature 50℃, time 3 hours, and enzyme dosage of 0.5% of the dry weight of fish skin; the enzymatic hydrolysis conditions for flavor protease-aminopeptidase are: temperature 40℃, time 3 hours, and enzyme dosage of 0.7% of the dry weight of fish skin; the enzymatic hydrolysis conditions for TG enzyme are: temperature 50℃, time 50 minutes, and enzyme dosage of 0.5% of the dry weight of fish skin.

[0068] In step S4: the weight of chicken carcass and chicken bones added is 10% of the meat matrix, the rotation speed is 2000 r / min, and the time is 2 min. In the second step, enzymatically hydrolyzed fish skin peptides are added, the rotation speed is 2500 r / min, and the time is 3 min. The final meat paste emulsion particle size is 50 mesh.

[0069] In step S5: sterilization treatment for 50 minutes;

[0070] Other technical features are the same as in Example 1.

[0071] Comparative Example 1

[0072] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that brewing yeast is not added and fish skin fermentation and deodorization in step S2 are not performed.

[0073] Other technical features are the same as in Example 1.

[0074] Comparative Example 2

[0075] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that the yeast fermentation time in step S2 is 12 hours.

[0076] Other technical features are the same as in Example 1.

[0077] Comparative Example 3

[0078] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that the yeast fermentation time in step S2 is 24 hours.

[0079] Other technical features are the same as in Example 1.

[0080] Comparative Example 4

[0081] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that collagenase is not added in step S3.

[0082] Other technical features are the same as in Example 1.

[0083] Comparative Example 5

[0084] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that, in step S3, flavor protease-aminopeptidase is not added.

[0085] Other technical features are the same as in Example 1.

[0086] Comparative Example 6

[0087] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that TG enzyme is not added in step S3.

[0088] Other technical features are the same as in Example 1.

[0089] Comparative Example 7

[0090] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that the fish skin peptide-directed enzymatic hydrolysis (tertiary enzymatic hydrolysis) in step S3 is not performed.

[0091] Other technical features are the same as in Example 1.

[0092] Comparative Example 8

[0093] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that, in step S4, the amount of enzymatically hydrolyzed fish skin peptide added is 1% of the weight of the meat matrix.

[0094] Other technical features are the same as in Example 1.

[0095] Comparative Example 9

[0096] A method for preparing minced meat, referring to Example 1, differs from Example 1 in that steps S1-S3 are not performed, and enzymatically hydrolyzed fish skin peptides are not added during the step-by-step chopping process.

[0097] Other technical features are the same as in Example 1.

[0098] test:

[0099] Test 1

[0100] After fermentation in step S2, the MFI (myofibril breakage index) of the fish products obtained in each example and comparative examples 1-3 was tested.

[0101] The test method is as follows: Take 4g of fermented fish meat (remove visible fat and connective tissue), add it to 40mL of 4℃ MFI buffer (100 mmol / L KCl, 11.2 mmol / L K2HPO4, 8.8 mmol / L KH2PO4, 1 mmol / L LEGTA, 1 mmol / L MgCl2, 1 mmol / L NaN3), and mix well; centrifuge at 10000 r / min for 2 min, slowly pour out the supernatant, continue stirring the precipitate in 40 mL of buffer to make a suspension, centrifuge at 10000 r / min for 2 min, slowly pour out the supernatant; make a suspension in 10 mL of buffer, and pass it through a copper sieve (20 mesh) to remove connective tissue and debris. The protein concentration of the myofibril suspension was determined by the biuret method. The protein concentration of the suspension was then adjusted to 0.5 mg / mL with MFI buffer solution, and the absorbance was measured at 540 nm. The MFI value was obtained by multiplying the result by 200.

[0102] The test results are shown in Table 1.

[0103] Table 1. MFI values ​​of each embodiment and Comparative Examples 1-3

[0104]

[0105] Shear force is an important indicator of meat tenderness. MFI represents the degree of myofibril degradation; the greater the degree of protein degradation, the higher the MFI value, the lower the shear force, and the greater the tenderness of the meat. As shown in Table 1, the MFI values ​​of the examples were higher than those of comparative examples 1-3, indicating that the addition of yeast can improve the tenderness of the meat.

[0106] Test 2

[0107] After the enzymatic hydrolysis in step S3 is completed, the degree of hydrolysis of the enzymatically hydrolyzed fish skin peptides obtained in each example and comparative examples 4-7 is tested.

[0108] The test method is as follows: Take 10 mL of unhydrolyzed fish skin fermentation broth, adjust the pH to 7.5 with 0.1 mol / L NaOH solution, slowly add 15 mL of neutral formaldehyde solution, and then titrate with 0.05 mol / L sodium hydroxide standard solution to pH=8.10. Record the volume of sodium hydroxide standard solution consumed in the titration (V0). Take 10 mL of enzymatically hydrolyzed fish skin peptides, adjust the pH to 7.5 with 0.1 mol / L NaOH solution, slowly add 15 mL of neutral formaldehyde solution, and then titrate with 0.05 mol / L sodium hydroxide standard solution to pH=8.10. Record the volume of sodium hydroxide standard solution consumed in the titration (V1).

[0109] Assuming the ratio of fish skin to water in the enzymatic hydrolysis formula is M:V, the formula for calculating the degree of hydrolysis DH is as follows:

[0110]

[0111] In the formula: V1 is the volume (mL) of NaOH solution consumed by 1 mL of hydrolysate;

[0112] V0 is the volume (mL) of NaOH solution consumed by 1 mL of blank solution;

[0113] V represents the volume of water used for mixing (mL);

[0114] C represents the concentration (mol / L) of the NaOH solution used in the titration.

[0115] 14.01 is the molar mass of nitrogen (g / mol);

[0116] 6.25 is the conversion factor for nitrogen to protein;

[0117] M represents the mass (g) of fish skin added to the ingredients;

[0118] "pro" refers to the protein content (%) of the fish skin added to the ingredients.

[0119] 0.05 mol / L NaOH solution: Weigh about 0.4 g of NaOH, dissolve it in a small amount of distilled water, and then dilute to a volumetric flask of 200 ml.

[0120] 0.1 mol / L NaOH solution: Weigh about 0.4 g of NaOH, dissolve it in a small amount of distilled water, and then dilute to a volumetric flask of 100 ml.

[0121] The test results are shown in Table 2.

[0122] Table 2. Degree of hydrolysis of each embodiment and comparative examples 4-7

[0123]

[0124] The degree of hydrolysis is essentially the proportion of peptide bonds in fish skin collagen that are broken by enzymes; the higher the degree of hydrolysis, the smaller the peptide segments. Table 2 shows that the degree of hydrolysis in each example is higher than that in comparative examples 4-7, indicating that the synergistic use of the three enzymes—collagenase, flavor protease-aminopeptidase, and TG enzyme—can improve the degree of hydrolysis of fish skin.

[0125] Test 3

[0126] After chopping in step S4, the fineness of the emulsified meat paste obtained in each example and comparative example was tested. The test method is as follows: 400g of meat paste was passed through a 30-mesh sieve, and the sieve passing rate was calculated.

[0127] The test results are shown in Table 3.

[0128] Table 3. Sieving rates of each embodiment and comparative example

[0129]

[0130] The fineness of the minced meat was positively correlated with the 30-mesh sieve pass rate; the higher the pass rate, the finer the meat. Table 3 shows that the pass rate of each embodiment was higher than that of the comparative embodiments, indicating that the synergy of "fermentation-enzymatic hydrolysis-appropriate amount of enzymatically hydrolyzed fish skin peptide addition" is the key to improving the fineness.

[0131] Test 4

[0132] After sterilization in step S5, the water retention of the products obtained in each embodiment and each comparative example was tested.

[0133] The test method is as follows: Take 15g of sample and record the initial mass (M1). Wrap the sample in 3 layers of filter paper and weigh the sample again after 10 minutes (M2).

[0134] The formula for calculating water retention capacity is as follows: Water retention capacity (%) = M2 / M1 × 100

[0135] The test results are shown in Table 4.

[0136] Table 4. Water retention capacity of each embodiment and comparative example

[0137]

[0138] Water retention is a crucial factor in ensuring product quality; better water retention leads to more stable product quality. Table 4 shows that the water retention of each example was higher than that of the comparative examples, indicating that the synergistic effect of fermentation, enzymatic hydrolysis, and the addition of an appropriate amount of enzymatically hydrolyzed fish skin peptides significantly reduces water loss and improves product juiciness and quality stability. Lack of enzymatic hydrolysis, absence of peptide addition, or insufficient fermentation will all lead to the breakdown of the water-locking mechanism and a significant decrease in water retention.

[0139] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier, characterized in that, Includes the following steps: S1. Fermentation: Crush the fish skin into small pieces, crush it using a low-temperature colloid mill, stir it evenly, and inoculate it with brewing yeast for fermentation. S2. Enzymatic hydrolysis: The material obtained in step S1 is successively added to collagenase, flavor protease-aminopeptidase and TG enzyme for enzymatic hydrolysis to obtain enzymatically hydrolyzed fish skin peptides. S3. Step-by-step chopping and mixing: Add the enzymatically hydrolyzed fish skin peptides obtained in step S2 to the meat matrix and chop and mix in steps to obtain a uniformly emulsified meat paste. In step S1, the fermentation parameters of the brewing yeast are as follows: the inoculum amount is 2-5% (v / w) of the dry weight of fish skin, and fermentation is carried out at 25-30℃, initial pH 5.0-7.0, and shaking speed of 100-200 r / min for 36-72 h. The amount of enzymatically hydrolyzed fish skin peptide added is 1.5-3.0% of the weight of the meat matrix.

2. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1, characterized in that, In step S2, the enzymatic hydrolysis conditions of the collagenase are: hydrolysis pH 5.0-7.0, hydrolysis temperature 30-50℃, hydrolysis time 1-3h, and the amount of enzyme added is 0.3-0.5% of the dry weight of the fish skin.

3. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1, characterized in that, In step S2, the enzymatic hydrolysis conditions of the flavor protease-aminopeptidase are: hydrolysis temperature 30-40℃, hydrolysis time 1-3h, total enzyme amount is 0.5-0.7% of the dry weight of fish skin, and the mass ratio of flavor protease to aminopeptidase is (1:3)-(3:1).

4. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1, characterized in that, In step S2, the enzymatic hydrolysis conditions of the TG enzyme are: hydrolysis temperature 40-50℃, hydrolysis time 30-50min, and enzyme dosage of 0.4-0.6% of the dry weight of the fish skin.

5. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1, characterized in that, The molecular weight of the enzymatically hydrolyzed fish skin peptides obtained in step S2 is concentrated in the range of 1000-3000 Da.

6. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1, characterized in that, After fermentation in step S1, the trimethylamine content in the system is ≤0.015mg / kg.

7. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1, characterized in that, In step S3, the chopping speed of the first step of the stepwise chopping process is 1500-2000 r / min, and the time is 2-3 min; the chopping speed of the second step is 2000-2500 r / min, and the time is 3-5 min.

8. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1 or 7, characterized in that, The final minced meat emulsion particle size obtained in step S3 is 30-50 mesh.

9. The method for preparing minced meat using enzymatically hydrolyzed fish skin peptides as an emulsifier according to claim 1, characterized in that, In step S1, the low-temperature colloid mill is used for crushing at a speed of 3000-5000 r / min for 2-5 min, with the particle size controlled at 100-200 μm, the solid-liquid ratio at (1:5)-(1:10) (g / mL), and water as the solvent.

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