Microecological preparation for improving meat quality of jinhua pigs and preparation method thereof

Abstract

The application discloses a kind of microecological preparation for improving meat quality of Jinhua pig and a preparation method thereof, comprising: selecting mixed strains and licorice powder, corn powder are mixed and fermented, freeze-drying to obtain licorice powder probiotic ferment powder;Coat the inner layer film on the surface of licorice powder probiotic ferment powder;Coat the outer barrier film on the surface of inner layer film, obtain the microecological preparation for improving meat quality of Jinhua pig.The application is fermented by bacillus subtilis, lactobacillus casei, yeast and licorice powder, corn powder, and the probiotic ferment obtained can maintain the balance of microorganisms in the intestinal tract of Jinhua pig, thereby ensuring the health and nutrition of Jinhua pig growth, regulating the intestinal flora of Jinhua pig by probiotics, regulating the digestion and metabolism of Jinhua pig, and improving the meat quality of Jinhua pig by regulating the way of digestion and nutrition absorption.The microecological preparation disclosed by the application adopts double-layer coating scheme, so that the microecological preparation has excellent enteric solubility and gastric acid resistance.

Description

Technical Field

[0001] This invention belongs to the field of microbial preparation technology. More specifically, this invention relates to a microecological preparation for improving the quality of Jinhua pork and its preparation method. Background Technology

[0002] Currently, industrial pig farming prioritizes rapid weight gain, leading to a decrease in intramuscular fat (IMF) content in pork (ideal value 2.5%–3.5%, but often <1.5%), affecting flavor and juiciness. Simultaneously, during slaughter and transportation, pigs are prone to stress, easily leading to muscle glycogen depletion and a sharp drop in pork pH, resulting in sour and darkened meat. In conventional pig farming, the widespread use of low-cost, large-scale feed has resulted in highly homogenized pork quality, characterized by bland taste and low tenderness. Therefore, common methods to improve pork quality include nutritional regulation, breed selection, and pre-slaughter electrical stimulation. However, nutritional regulation is costly and unsuitable for industrial pig farming; breed selection has a long cycle (usually over 5 years), and pre-slaughter electrical stimulation not only incurs high equipment costs but also fails to fundamentally improve pork quality.

[0003] Currently, feed formulation improvement has become a low-cost and quick way to improve pork quality. Feed formulation improvement includes microbial fermentation of feed and the addition of microbial preparations. The addition of microbial preparations is based on the fact that probiotics can regulate the balance of the pig's intestinal microecology, promote intestinal health, and thus improve pork quality. Studies have shown that a large number of microbial communities exist in the pig's intestines, and the balance of these communities is crucial for the pig's digestion and metabolism. For example, lactic acid bacteria and Bacillus can inhibit the reproduction of pathogenic bacteria such as Escherichia coli, reducing intestinal inflammation. At the same time, probiotics can also enhance intestinal barrier function, upregulate tight junction proteins (the interaction between probiotics and the intestinal epithelial layer enhances the expression of tight junction proteins in intestinal epithelial cells), reduce botulinum toxin entry into the bloodstream, reduce systemic inflammation in pigs, and reduce muscle protein breakdown, thereby reducing the ammonia nitrogen and acid content in pork and improving pork quality.

[0004] Probiotics improve the color of pork, intramuscular fat content, and tenderness by increasing the redness of the meat, improving the content of fatty acids (oleic acid, linoleic acid, linolenic acid, etc.), flavor amino acids (glutamic acid, aspartic acid, etc.), and volatile flavor compounds (alcohols, aldehydes, ketones). Beneficial bacteria and their fermentation metabolites—bioactive factors—enhance muscle antioxidant levels, regulate the gut microbiota related to sugar and fat metabolism, and their metabolites, such as short-chain fatty acids, lipopolysaccharides, trimethylamine oxide, bile acid metabolites, and tryptophan derivatives, regulate the body's protein and lipid metabolism.

[0005] Current research on probiotics improving pork quality mainly focuses on microbial fermented feed, with limited research on the effects of microecological coated preparations on pork quality. However, single-strain or multi-strain fermented feeds suffer from individual variability; different pigs have varying requirements for the types and amounts of probiotics, and different probiotic strains have different effects on different pigs. Microecological coated preparations can effectively address these issues by adjusting the type of coated bacteria and the amount of microecological preparation added to the feed to eliminate these individual differences. Summary of the Invention

[0006] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0007] To achieve these objectives and other advantages according to the present invention, a method for preparing a microecological preparation for improving the quality of Jinhua pork is provided, comprising the following steps: Step 1: Select a mixed bacterial strain and mix it with licorice powder and corn flour for fermentation, then freeze-dry to obtain licorice powder probiotic fermentation product powder; Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane; Step 3: Coat the surface of the inner membrane with an outer barrier membrane to obtain a microecological preparation that improves the quality of Jinhua pork.

[0008] Preferably, in step one, the mixed microbial strain includes Bacillus subtilis, Lactobacillus casei, and yeast, with an inoculation volume ratio of 2-6:1-2:2; the mass ratio of licorice powder to corn flour is 2-5:1, and the total mass of licorice powder and corn flour to the inoculation volume ratio of the mixed microbial strain is 300-700g:1-10mL.

[0009] Preferably, in step one, the fermentation temperature is 25~30℃ and the fermentation time is 4~21 days.

[0010] Preferably, in step two, the specific method for coating the surface of the licorice powder probiotic fermentation product with an inner membrane includes: S21. Dissolve chitosan in 1-3 wt% glacial acetic acid solution to obtain chitosan solution; mix chitosan solution with sodium carboxymethyl cellulose solution, stir magnetically at 300-500 rpm for 30-60 min, adjust pH to 5.5-6.0 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S22. Place the colloidal mixture in a 4°C ice-water bath and add 2wt% sodium tripolyphosphate solution dropwise while stirring continuously at 200rpm. After the addition is complete, stop stirring and let stand for 2~4h to obtain the crosslinked system. S23. Disperse the licorice powder probiotic ferment in the cross-linking system in S22, stir at 100-200 rpm for 1-3 hours at 30-40℃, filter out the water, and spray dry to obtain the licorice powder probiotic ferment with inner membrane coating.

[0011] Preferably, in step S21, the concentration of the chitosan solution is 2-5 wt%, the concentration of sodium carboxymethyl cellulose is 1-2 wt%, and the volume ratio of the chitosan solution to the sodium carboxymethyl cellulose solution is 1-2:2-5. In step S22, the amount of sodium tripolyphosphate solution used accounts for 1% to 25% of the volume of the colloidal mixture; In step S23, the ratio of licorice powder probiotic fermentation product powder to cross-linking system is 10~20g:100~500mL.

[0012] Preferably, in step S23, the inlet temperature of the spray dryer is 70~85℃ and the outlet temperature is 35~55℃.

[0013] Preferably, in step three, the specific method for coating the surface of the inner membrane with an outer barrier membrane includes: S31. Dissolve chitosan with a deacylation degree of 85%–95% in 1–3 wt% glacial acetic acid solution to obtain a chitosan solution; heat the chitosan solution to 50–60°C, add polylactic acid powder in portions, stir and mix evenly to obtain a suspension; add glycerol and triethyl citrate dropwise to the suspension, stir at 200–400 rpm for 10–30 min to obtain a modified chitosan gel solution; S32, Particle size distribution D 90 Nano-SiO2 powder with a particle size of less than 50 nm is dispersed in modified chitosan colloid, magnetically stirred at 400~600 rpm for 30~40 min, sodium tripolyphosphate is added as a crosslinking agent, and the temperature is raised to 60~80℃ and kept at that temperature for 1~12 h. After cooling, an external barrier membrane colloid is obtained. S33. Disperse the licorice powder and probiotic fermentation product powder coated with the inner membrane in the outer barrier membrane colloid, stir at 100-200 rpm for 1-3 hours at 30-40℃, filter out the water, and spray dry to obtain the microecological preparation.

[0014] Preferably, in step S31, the concentration of the chitosan solution is 2-5 wt%, and the ratio of the chitosan solution to polylactic acid powder, glycerol, and triethyl citrate is 100-250 mL: 0.1-1 g: 0.1-0.5 mL: 0.1-0.3 mL. In step S32, the ratio of chitosan solution, nano-SiO2 powder, and sodium tripolyphosphate is 100~250mL:0.2~0.8g:0.05~0.1g. In S33, the ratio of licorice powder and probiotic fermentation powder coated by the inner membrane to the outer barrier membrane colloid is 10~20g:100~500mL.

[0015] Preferably, in step S33, the inlet temperature of the spray dryer is 70~85℃ and the outlet temperature is 35~55℃.

[0016] A microecological preparation for improving the quality of Jinhua pork, wherein the microecological preparation for improving the quality of Jinhua pork is prepared by the above-mentioned method for preparing a microecological preparation for improving the quality of Jinhua pork.

[0017] The present invention has at least the following beneficial effects: This invention involves fermenting Bacillus subtilis, Lactobacillus casei, and yeast with licorice powder and corn flour to obtain a probiotic fermentation product that can regulate the microbial balance in the intestines of Jinhua pigs. When Jinhua pigs are fed this microecological preparation during their breeding process, the preparation intervenes in the intestinal flora, increasing the number of Bacillus subtilis, Lactobacillus casei, and yeast colonies, thereby improving the digestibility and absorption of feed and fruits, and promoting the growth of Jinhua pigs. Simultaneously, the increase in probiotics helps inhibit the production and reproduction of harmful bacteria, reducing the use of antibiotics. This method of regulating the digestive and metabolic processes of Jinhua pigs through probiotic intervention can effectively improve the meat quality of Jinhua pigs.

[0018] The microecological preparation disclosed in this invention employs a double-layer coating scheme. The inner membrane is prepared by cross-linking chitosan with sodium carboxymethyl cellulose as the main raw material using sodium tripolyphosphate as a cross-linking agent. This inner membrane not only effectively protects the probiotic fermentation products of licorice powder within, maintaining the activity of Bacillus subtilis, Lactobacillus casei, and yeast, but also exhibits excellent enteric solubility in the intestinal fluid of pigs (pH ≥ 6.8), enabling the targeted release of each probiotic within the pig's intestines. Sodium tripolyphosphate reacts with the protonated -NH3 of chitosan in the acidic environment of gastric juice (pH < 5.0). + An electrostatic cross-linked network is formed; when ≥6.8, the -NH3 group of chitosan... + Deprotonation transforms the sodium tripolyphosphate into -NH2, eliminating its electrostatic attraction with sodium tripolyphosphate. Simultaneously, the ionization of the -COO⁻ group in sodium carboxymethyl cellulose is enhanced, leading to: sodium tripolyphosphate detaching from the chitosan crosslinking points, the ionic bond between sodium carboxymethyl cellulose and chitosan breaking, and the three-dimensional network structure of the inner membrane disintegrating due to water absorption, resulting in excellent enteric solubility of the inner membrane.

[0019] The outer barrier membrane of the microecological preparation disclosed in this invention is mainly used to improve the gastric acid resistance of the microecological preparation, enhance its resistance to acidic conditions (pH=1.0~2.0), and increase the activity of Bacillus subtilis, Lactobacillus casei, and yeast. This means it can increase the number of probiotics released and proliferating in the intestines, thus enhancing the intervention and regulation effect on the intestinal flora balance of Jinhua pigs. Specifically, chitosan is cross-linked and modified by lactic acid bacteria, significantly reducing its acid solubility. Combined with cross-linking with nano-silica powder, this further improves the acid resistance of the outer barrier membrane. Both the inner and outer barrier membranes of the microecological preparation of this invention use chitosan as a raw material, resulting in excellent compatibility and a tighter bond between the two membranes, making them less prone to peeling during long-term storage.

[0020] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0021] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0022] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0023] The Bacillus subtilis used in the various embodiments and comparative examples was purchased from Fangjue Biotechnology, strain number HZB199346; Lactobacillus casei was purchased from Fangjue Biotechnology, strain number HZB361958; and yeast was purchased from Fangjue Biotechnology, strain number HZB205362. The activation methods for each strain are existing technologies and will not be described in detail here.

[0024] Example 1

[0025] A method for preparing a microecological preparation to improve the quality of Jinhua pork includes the following steps: Step 1: Activate the purchased Bacillus subtilis, Lactobacillus casei, and yeast separately to obtain bacterial solutions. The concentrations of the bacterial solutions prepared for Bacillus subtilis, Lactobacillus casei, and yeast are 4.4 × 10⁻⁶. 8 CFU / mL, 2.6×10 8 CFU / mL, 1.2×10 8 CFU / mL, 6mL of Bacillus subtilis culture, 2mL of Lactobacillus casei culture, and 2mL of yeast culture were mixed with 500g of licorice powder and 100g of corn flour for fermentation. After fermentation at 25℃ for 4 days, the mixture was freeze-dried at -18℃ to obtain licorice powder probiotic fermentation powder. Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane. Specific methods include: S21. Dissolve chitosan in 1 wt% glacial acetic acid solution to obtain 2 wt% chitosan solution; mix 100 mL of chitosan solution with 300 mL of 2 wt% sodium carboxymethyl cellulose solution, stir magnetically at 300 rpm for 40 min, adjust the pH to 5.5 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S22. Place the colloidal mixture in a 4°C ice-water bath and add 10 mL of 2 wt% sodium tripolyphosphate solution dropwise while stirring continuously at 200 rpm. After the addition is complete, stop stirring and let stand for 4 h to obtain the crosslinked system. S23. Disperse 20g of licorice powder probiotic fermentation product powder in the cross-linking system in S22. Stir at 200rpm for 2 hours at 30℃. After filtering out the water, spray dry to obtain licorice powder probiotic fermentation product with inner membrane coating. The inlet temperature of spray drying is 80℃ and the outlet temperature is 40℃. Step 3: Coat the surface of the inner membrane with an outer barrier membrane. Specific methods include: S31. Dissolve chitosan with a deacylation degree of 90% in 1wt% glacial acetic acid solution to obtain a 2wt% chitosan solution; heat 200mL of chitosan solution to 50℃, and add 1g of polylactic acid powder in two equal portions, stirring and mixing evenly to obtain a suspension; add 0.5mL of glycerol and 0.2mL of triethyl citrate to the suspension, and stir at 400rpm for 30min to obtain a modified chitosan gel solution; S32, 0.2g of particle size distribution D 90 45nm nano-SiO2 powder was dispersed in 250mL of modified chitosan colloid, magnetically stirred at 400rpm for 30min, 0.05g sodium tripolyphosphate was added as a crosslinking agent, and the temperature was raised to 80℃ and kept at that temperature for 6h. After cooling, the external barrier membrane colloid was obtained. S33. Disperse 20g of licorice powder and probiotic fermentation powder coated with inner membrane in 200mL of outer barrier membrane colloid. Stir at 100rpm for 1h at 40℃. After filtering out the water, spray dry to obtain a microecological preparation for improving the quality of Jinhua pork. The inlet temperature of spray drying is 85℃ and the outlet temperature is 40℃.

[0026] Example 2

[0027] A method for preparing a microecological preparation to improve the quality of Jinhua pork includes the following steps: Step 1: Activate the purchased Bacillus subtilis, Lactobacillus casei, and yeast separately to obtain bacterial solutions. The concentrations of the bacterial solutions prepared for Bacillus subtilis, Lactobacillus casei, and yeast are 4.4 × 10⁻⁶. 8CFU / mL, 2.6×10 8 CFU / mL, 1.2×10 8 CFU / mL, 6mL of Bacillus subtilis culture, 2mL of Lactobacillus casei culture, and 2mL of yeast culture were mixed with 500g of licorice powder and 100g of corn flour for fermentation. After fermentation at 25℃ for 5 days, the mixture was freeze-dried at -18℃ to obtain licorice powder probiotic fermentation product powder. Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane. Specific methods include: S21. Dissolve chitosan in 1 wt% glacial acetic acid solution to obtain 2 wt% chitosan solution; mix 100 mL of chitosan solution with 400 mL of 2 wt% sodium carboxymethyl cellulose solution, stir magnetically at 300 rpm for 40 min, adjust the pH to 5.5 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S22. Place the colloidal mixture in a 4°C ice-water bath and add 20 mL of 2 wt% sodium tripolyphosphate solution dropwise while stirring continuously at 200 rpm. After the addition is complete, stop stirring and let stand for 4 h to obtain the crosslinked system. S23. Disperse 20g of licorice powder probiotic fermentation product powder in the cross-linking system in S22. Stir at 200rpm for 2 hours at 30℃. After filtering out the water, spray dry to obtain licorice powder probiotic fermentation product with inner membrane coating. The inlet temperature of spray drying is 80℃ and the outlet temperature is 40℃. Step 3: Coat the surface of the inner membrane with an outer barrier membrane. Specific methods include: S31. Dissolve chitosan with a deacylation degree of 90% in 1wt% glacial acetic acid solution to obtain a 2wt% chitosan solution; heat 250mL of chitosan solution to 50℃, and add 1g of polylactic acid powder in two equal portions, stirring and mixing evenly to obtain a suspension; add 0.5mL of glycerol and 0.3mL of triethyl citrate to the suspension, and stir at 400rpm for 30min to obtain a modified chitosan gel solution; S32, 0.3g of particle size distribution D 90 45nm nano-SiO2 powder was dispersed in 250mL of modified chitosan colloid, magnetically stirred at 400rpm for 30min, 0.05g sodium tripolyphosphate was added as a crosslinking agent, and the temperature was raised to 80℃ and kept at that temperature for 6h. After cooling, the external barrier membrane colloid was obtained. S33. Disperse 20g of licorice powder and probiotic fermentation powder coated with inner membrane in 200mL of outer barrier membrane colloid. Stir at 100rpm for 1h at 40℃. After filtering out the water, spray dry to obtain a microecological preparation for improving the quality of Jinhua pork. The inlet temperature of spray drying is 85℃ and the outlet temperature is 40℃.

[0028] Example 3

[0029] A method for preparing a microecological preparation to improve the quality of Jinhua pork includes the following steps: Step 1: Activate the purchased Bacillus subtilis, Lactobacillus casei, and yeast separately to obtain bacterial solutions. The concentrations of the bacterial solutions prepared for Bacillus subtilis, Lactobacillus casei, and yeast are 4.4 × 10⁻⁶. 8 CFU / mL, 2.6×10 8 CFU / mL, 1.2×10 8 CFU / mL, 6mL of Bacillus subtilis culture, 2mL of Lactobacillus casei culture, and 2mL of yeast culture were mixed with 500g of licorice powder and 100g of corn flour for fermentation. After fermentation at 25℃ for 4 days, the mixture was freeze-dried at -18℃ to obtain licorice powder probiotic fermentation powder. Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane. Specific methods include: S21. Dissolve chitosan in 1 wt% glacial acetic acid solution to obtain 2 wt% chitosan solution; mix 200 mL of chitosan solution with 300 mL of 2 wt% sodium carboxymethyl cellulose solution, stir magnetically at 300 rpm for 40 min, adjust the pH to 5.5 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S22. Place the colloidal mixture in a 4°C ice-water bath and add 15 mL of 2 wt% sodium tripolyphosphate solution dropwise while stirring continuously at 200 rpm. After the addition is complete, stop stirring and let stand for 4 h to obtain the crosslinked system. S23. Disperse 20g of licorice powder probiotic fermentation product powder in the cross-linking system in S22. Stir at 200rpm for 2 hours at 30℃. After filtering out the water, spray dry to obtain licorice powder probiotic fermentation product with inner membrane coating. The inlet temperature of spray drying is 80℃ and the outlet temperature is 40℃. Step 3: Coat the surface of the inner membrane with an outer barrier membrane. Specific methods include: S31. Dissolve chitosan with a deacylation degree of 90% in 1wt% glacial acetic acid solution to obtain a 2wt% chitosan solution; heat 200mL of chitosan solution to 55℃, and add 1g of polylactic acid powder in two equal portions, stirring and mixing evenly to obtain a suspension; add 0.5mL of glycerol and 0.2mL of triethyl citrate to the suspension, and stir at 400rpm for 30min to obtain a modified chitosan gel solution; S32, 0.4g of particle size distribution D 9045nm nano-SiO2 powder was dispersed in 250mL of modified chitosan colloid, magnetically stirred at 400rpm for 30min, 0.05g sodium tripolyphosphate was added as a crosslinking agent, and the temperature was raised to 80℃ and kept at that temperature for 6h. After cooling, the external barrier membrane colloid was obtained. S33. Disperse 20g of licorice powder and probiotic fermentation powder coated with inner membrane in 200mL of outer barrier membrane colloid. Stir at 100rpm for 1h at 40℃. After filtering out the water, spray dry to obtain a microecological preparation for improving the quality of Jinhua pork. The inlet temperature of spray drying is 85℃ and the outlet temperature is 40℃.

[0030] Comparative Example 1 A method for preparing a microecological preparation to improve the quality of Jinhua pork includes the following steps: Step 1: Activate the purchased Bacillus subtilis, Lactobacillus casei, and yeast separately to obtain bacterial solutions. The concentrations of the bacterial solutions prepared for Bacillus subtilis, Lactobacillus casei, and yeast are 4.4 × 10⁻⁶. 8 CFU / mL, 2.6×10 8 CFU / mL, 1.2×10 8 CFU / mL, 6mL of Bacillus subtilis culture, 2mL of Lactobacillus casei culture, and 2mL of yeast culture were mixed with 500g of licorice powder and 100g of corn flour for fermentation. After fermentation at 25℃ for 4 days, the mixture was freeze-dried at -18℃ to obtain licorice powder probiotic fermentation powder. Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane. Specific methods include: S21. Dissolve chitosan in 1 wt% glacial acetic acid solution to obtain 2 wt% chitosan solution; mix 100 mL of chitosan solution with 300 mL of 2 wt% sodium carboxymethyl cellulose solution, stir magnetically at 300 rpm for 40 min, adjust the pH to 5.5 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S23. Disperse 20g of licorice powder probiotic fermentation product powder in the colloidal mixture in S21, stir at 200rpm for 2h at 30℃, filter out water, and spray dry to obtain licorice powder probiotic fermentation product with inner membrane coating. The inlet temperature of spray drying is 80℃ and the outlet temperature is 40℃. Step 3: Coat the surface of the inner membrane with an outer barrier membrane. Specific methods include: S31. Dissolve chitosan with a deacylation degree of 90% in 1wt% glacial acetic acid solution to obtain a 2wt% chitosan solution; heat 200mL of chitosan solution to 50℃, and add 1g of polylactic acid powder in two equal portions, stirring and mixing evenly to obtain a suspension; add 0.5mL of glycerol and 0.2mL of triethyl citrate to the suspension, and stir at 400rpm for 30min to obtain a modified chitosan gel solution; S32, 0.2g of particle size distribution D 90 45nm nano-SiO2 powder was dispersed in 250mL of modified chitosan colloid, magnetically stirred at 400rpm for 30min, 0.05g sodium tripolyphosphate was added as a crosslinking agent, and the temperature was raised to 80℃ and kept at that temperature for 6h. After cooling, the external barrier membrane colloid was obtained. S33. Disperse 20g of licorice powder and probiotic fermentation powder coated with inner membrane in 200mL of outer barrier membrane colloid. Stir at 100rpm for 1h at 40℃. After filtering out the water, spray dry to obtain a microecological preparation for improving the quality of Jinhua pork. The inlet temperature of spray drying is 85℃ and the outlet temperature is 40℃.

[0031] Comparative Example 2 A method for preparing a microecological preparation to improve the quality of Jinhua pork includes the following steps: Step 1: Activate the purchased Bacillus subtilis, Lactobacillus casei, and yeast separately to obtain bacterial solutions. The concentrations of the bacterial solutions prepared for Bacillus subtilis, Lactobacillus casei, and yeast are 4.4 × 10⁻⁶. 8 CFU / mL, 2.6×10 8 CFU / mL, 1.2×10 8 CFU / mL, 6mL of Bacillus subtilis culture, 2mL of Lactobacillus casei culture, and 2mL of yeast culture were mixed with 500g of licorice powder and 100g of corn flour for fermentation. After fermentation at 25℃ for 4 days, the mixture was freeze-dried at -18℃ to obtain licorice powder probiotic fermentation powder. Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane. Specific methods include: S21. Dissolve chitosan in 1 wt% glacial acetic acid solution to obtain 2 wt% chitosan solution; mix 100 mL of chitosan solution with 300 mL of 2 wt% sodium carboxymethyl cellulose solution, stir magnetically at 300 rpm for 40 min, adjust the pH to 5.5 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S22. Place the colloidal mixture in a 4°C ice-water bath and add 10 mL of 2 wt% genipin solution dropwise while stirring continuously at 200 rpm. After the addition is complete, stop stirring and let stand for 4 h to obtain the crosslinked system. S23. Disperse 20g of licorice powder probiotic fermentation product powder in the cross-linking system in S22. Stir at 200rpm for 2 hours at 30℃. After filtering out the water, spray dry to obtain licorice powder probiotic fermentation product with inner membrane coating. The inlet temperature of spray drying is 80℃ and the outlet temperature is 40℃. Step 3: Coat the surface of the inner membrane with an outer barrier membrane. Specific methods include: S31. Dissolve chitosan with a deacylation degree of 90% in 1wt% glacial acetic acid solution to obtain a 2wt% chitosan solution; heat 200mL of chitosan solution to 50℃, and add 1g of polylactic acid powder in two equal portions, stirring and mixing evenly to obtain a suspension; add 0.5mL of glycerol and 0.2mL of triethyl citrate to the suspension, and stir at 400rpm for 30min to obtain a modified chitosan gel solution; S32, 0.2g of particle size distribution D 90 45nm nano-SiO2 powder was dispersed in 250mL of modified chitosan colloid, magnetically stirred at 400rpm for 30min, 0.05g sodium tripolyphosphate was added as a crosslinking agent, and the temperature was raised to 80℃ and kept at that temperature for 6h. After cooling, the external barrier membrane colloid was obtained. S33. Disperse 20g of licorice powder and probiotic fermentation powder coated with inner membrane in 200mL of outer barrier membrane colloid. Stir at 100rpm for 1h at 40℃. After filtering out the water, spray dry to obtain a microecological preparation for improving the quality of Jinhua pork. The inlet temperature of spray drying is 85℃ and the outlet temperature is 40℃.

[0032] Comparative Example 3 A method for preparing a microecological preparation to improve the quality of Jinhua pork includes the following steps: Step 1: Activate the purchased Bacillus subtilis, Lactobacillus casei, and yeast separately to obtain bacterial solutions. The concentrations of the bacterial solutions prepared for Bacillus subtilis, Lactobacillus casei, and yeast are 4.4 × 10⁻⁶. 8 CFU / mL, 2.6×10 8 CFU / mL, 1.2×10 8 CFU / mL, 6mL of Bacillus subtilis culture, 2mL of Lactobacillus casei culture, and 2mL of yeast culture were mixed with 500g of licorice powder and 100g of corn flour for fermentation. After fermentation at 25℃ for 4 days, the mixture was freeze-dried at -18℃ to obtain licorice powder probiotic fermentation powder. Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane. Specific methods include: S21. Dissolve chitosan in 1 wt% glacial acetic acid solution to obtain 2 wt% chitosan solution; mix 100 mL of chitosan solution with 300 mL of 2 wt% sodium carboxymethyl cellulose solution, stir magnetically at 300 rpm for 40 min, adjust the pH to 5.5 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S22. Place the colloidal mixture in a 4°C ice-water bath and add 10 mL of 2 wt% sodium tripolyphosphate solution dropwise while stirring continuously at 200 rpm. After the addition is complete, stop stirring and let stand for 4 h to obtain the crosslinked system. S23. Disperse 20g of licorice powder probiotic fermentation product powder in the cross-linking system in S22. Stir at 200rpm for 2 hours at 30℃. After filtering out the water, spray dry to obtain licorice powder probiotic fermentation product with inner membrane coating. The inlet temperature of spray drying is 80℃ and the outlet temperature is 40℃. Step 3: Coat the surface of the inner membrane with an outer barrier membrane. Specific methods include: S31, 0.2g of particle size distribution D 90 45nm nano-SiO2 powder was dispersed in 250mL of 2wt% chitosan colloid solution, magnetically stirred at 400rpm for 30min, 0.05g sodium tripolyphosphate was added as a crosslinking agent, and the temperature was raised to 80℃ and kept at that temperature for 6h. After cooling, the external barrier membrane colloid was obtained. S32. Disperse 20g of licorice powder and probiotic fermentation powder coated with inner membrane in 200mL of outer barrier membrane colloid. Stir at 100rpm for 1h at 40℃. After filtering out the water, spray dry to obtain a microecological preparation for improving the quality of Jinhua pork. The inlet temperature of spray drying is 85℃ and the outlet temperature is 40℃.

[0033] The gastric acid resistance and enteric coagulation properties of the licorice powder probiotic ferments coated with inner membranes prepared in step two of Examples 1-3 and Comparative Examples 1-3 were determined using an in vitro simulation method.

[0034] The formula for preparing the simulated gastric fluid for pigs was as follows: 0.40 g NaCl, 0.50 g mucin, and 0.20 g pregelatinized starch were dissolved in 180 mL of sterile water. The solution was heated to 37°C and stirred until clear. The pH was adjusted to 2.0 with HCl, followed by the addition of 0.64 g pepsin. After dissolving, the solution was sterilized through a 0.22 μm filter membrane. Distilled water was added to bring the volume to 200 mL, and the solution was incubated at 37°C for 30 min. Six equal portions of the simulated gastric fluid were prepared according to the above formula. 0.5 g of a probiotic preparation was added to each of the sterile simulated gastric fluids, and the mixture was anaerobically cultured at 37°C on a shaker for 2 h. The samples were diluted, spread, and counted at 0 and 2 h. The total survival rate of the three probiotics was calculated and the results are shown in Table 1.

[0035] Table 1 Survival rate data of bacterial strains in each sample

[0036] As can be seen from the table above, the strains in the microecological preparations prepared in Examples 1-3 have a higher survival rate in in vitro gastric acid simulation, indicating that the microecological preparations prepared in Examples 1-3 have higher resistance to gastric acid.

[0037] The formula for preparing the simulated intestinal fluid for pigs is as follows: Dissolve 6.80g potassium dihydrogen phosphate, 5.0g trypsin, 5.0g lipase, 3.0g porcine bile salts, 0.24g CaCl2·2H2O, and 0.08g L-α-phosphatidylcholine in sterile water, adjust the pH to 6.8 with sodium hydroxide solution, and finally bring the volume to 1000mL with sterile water.

[0038] Six equal portions of simulated intestinal fluid were prepared according to the above formula. 5.0 g of the licorice powder probiotic fermentation product with inner membrane coating prepared in step two of Examples 1-3 and Comparative Examples 1-3 were dispersed in the simulated intestinal fluid. The mixture was shaken anaerobically at 37°C for 2 hours. After standing, the supernatant and precipitate were collected, and the viable bacterial counts of the supernatant and precipitate were measured separately. The total viable bacterial count was obtained by adding the viable bacterial counts of the supernatant and the total viable bacterial count. The release rate of the licorice powder probiotic fermentation product with inner membrane coating was then obtained, as shown in Table 2. Table 2. Intestinal fluid release rate of licorice powder probiotic fermentation product coated with inner membrane.

[0039] As can be seen from the table above, the release rate of the licorice powder probiotic fermentation products with inner membrane coating prepared in Examples 1-3 was significantly higher than that in Comparative Examples 1-2.

[0040] Four hundred 7-month-old Jinhua pigs were randomly divided into four groups for a feeding experiment. The feed formula used was 55% corn, 20% wheat bran, 14% soybean meal, 5% cottonseed meal, 5% fishmeal, 0.5% dicalcium phosphate, and 0.5% salt. The microecological preparations prepared in Examples 1-3 were added to the feed at a ratio of 4 kg:1 t. Three groups were fed the feed containing the microecological preparations from Examples 1-3, while the third group served as a control with the feed without the microecological preparations. After 30 days of feeding, the backfat thickness, intramuscular fat content, and fecal probiotic load of each group of Jinhua pigs were measured, and the average values ​​were calculated. The results are shown in the table below. Table 3. Feeding test results for Jinhua pigs

[0041] As can be seen from the table above, after feeding the Jinhua pigs with the microecological preparations of Examples 1-3, the backfat thickness was significantly reduced and the intramuscular fat content was significantly increased, indicating that feeding the microecological preparations prepared in Examples 1-3 can improve the meat quality of Jinhua pigs to a certain extent.

[0042] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0043] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A method for preparing a microecological preparation to improve the quality of Jinhua pork, characterized in that, Includes the following steps: Step 1: Select a mixed bacterial strain and mix it with licorice powder and corn flour for fermentation, then freeze-dry to obtain licorice powder probiotic fermentation product powder; Step 2: Coat the surface of the licorice powder probiotic fermentation product with an inner membrane; Step 3: Coat the surface of the inner membrane with an outer barrier membrane to obtain a microecological preparation that improves the quality of Jinhua pork; In step one, the mixed strain includes Bacillus subtilis, Lactobacillus casei, and yeast, with an inoculation volume ratio of 2-6:1-2:2; the mass ratio of licorice powder to corn flour is 2-5:1, and the ratio of the total mass of licorice powder and corn flour to the inoculation volume of the mixed strain is 300-700g:1-10mL. In step two, the specific method for coating the surface of the licorice powder probiotic fermentation product with an inner membrane includes: S21. Dissolve chitosan in 1-3 wt% glacial acetic acid solution to obtain chitosan solution; mix chitosan solution with sodium carboxymethyl cellulose solution, stir magnetically at 300-500 rpm for 30-60 min, adjust pH to 5.5-6.0 with NaOH solution, and continue stirring for 30 min to obtain colloidal mixture; S22. Place the colloidal mixture in a 4°C ice-water bath and add 2wt% sodium tripolyphosphate solution dropwise while stirring continuously at 200rpm. After the addition is complete, stop stirring and let stand for 2~4h to obtain the crosslinking system. S23. Disperse the licorice powder probiotic ferment in the cross-linking system in S22, stir at 100-200 rpm for 1-3 hours at 30-40℃, filter out the water, and spray dry to obtain the licorice powder probiotic ferment with inner membrane coating. In step three, the specific method for coating the surface of the inner membrane with an outer barrier membrane includes: S31. Dissolve chitosan with a deacylation degree of 85%~95% in 1~3wt% glacial acetic acid solution to obtain chitosan solution; heat the chitosan solution to 50~60℃, add polylactic acid powder in portions, stir and mix evenly to obtain suspension; add glycerol and triethyl citrate dropwise to the suspension, stir at 200~400rpm for 10~30min to obtain modified chitosan gel solution; S32, Particle size distribution D 90 Nano-SiO2 powder with a particle size of less than 50 nm is dispersed in modified chitosan colloid, magnetically stirred at 400~600 rpm for 30~40 min, sodium tripolyphosphate is added as a crosslinking agent, and the temperature is raised to 60~80℃ and kept at that temperature for 1~12 h. After cooling, an external barrier membrane colloid is obtained. S33. Disperse the licorice powder and probiotic fermentation product powder coated with the inner membrane in the outer barrier membrane colloid, stir at 100-200 rpm for 1-3 hours at 30-40℃, filter out the water, and spray dry to obtain the microecological preparation.

2. The method for preparing the microecological preparation for improving the quality of Jinhua pork as described in claim 1, characterized in that, In step one, the fermentation temperature is 25~30℃ and the fermentation time is 4~21 days.

3. The method for preparing the microecological preparation for improving the quality of Jinhua pork as described in claim 1, characterized in that, In step S21, the concentration of the chitosan solution is 2-5 wt%, and the concentration of sodium carboxymethyl cellulose is 1-2 wt%; the volume ratio of the chitosan solution to the sodium carboxymethyl cellulose solution is 1-2:2-5. In step S22, the amount of sodium tripolyphosphate solution used accounts for 1% to 25% of the volume of the colloidal mixture; In step S23, the ratio of licorice powder probiotic fermentation product powder to cross-linking system is 10~20g:100~500mL.

4. The method for preparing the microecological preparation for improving the quality of Jinhua pork as described in claim 1, characterized in that, In step S23, the inlet temperature of the spray dryer is 70~85℃, and the outlet temperature is 35~55℃.

5. The method for preparing the microecological preparation for improving the quality of Jinhua pork as described in claim 1, characterized in that, In step S31, the concentration of the chitosan solution is 2-5 wt%, and the ratio of chitosan solution to polylactic acid powder, glycerol, and triethyl citrate is 100-250 mL: 0.1-1 g: 0.1-0.5 mL: 0.1-0.3 mL. In step S32, the ratio of chitosan solution, nano-SiO2 powder, and sodium tripolyphosphate is 100~250mL:0.2~0.8g:0.05~0.1g. In S33, the ratio of licorice powder and probiotic fermentation powder coated by the inner membrane to the outer barrier membrane colloid is 10~20g:100~500mL.

6. The method for preparing the microecological preparation for improving the quality of Jinhua pork as described in claim 1, characterized in that, In S33, the inlet temperature of the spray dryer is 70~85℃, and the outlet temperature is 35~55℃.

7. A microecological preparation for improving the quality of Jinhua pork, characterized in that, The microecological preparation for improving the quality of Jinhua pork is prepared by the method for preparing the microecological preparation for improving the quality of Jinhua pork according to any one of claims 1 to 6.

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