Method for improving stability of yellow wine

Abstract

The invention provides a method for improving the stability of yellow wine. Comprising the following steps: S1, esterifying carrageenan with glyceryl monooleate, and carrying out ball milling treatment on the esterified carrageenan; s2, immobilizing pectinase and galactosidase liquid with sodium alginate to prepare gel; s3, jointly preparing composite gel from the ball-milled / esterified carrageenan and the sodium alginate gel with the immobilized compound enzyme; and S4, putting the composite gel into yellow wine, stirring, performing ultrasonic treatment, performing microwave treatment, standing, and centrifuging to obtain supernate. The composite gel is prepared from the ball-milled / esterified carrageenan and the sodium alginate gel for immobilizing pectinase and galactosidase, the ball-milled / esterified carrageenan can improve the stability of the yellow rice wine and reduce the formation of precipitates, and ball milling endows the esterified carrageenan with interfacial adsorbability, so that the effect of purifying the yellow rice wine is achieved; the added ball-milled / esterified carrageenan can interact with substances generated by decomposition of pectinase and galactosidase, so that the stability of the yellow rice wine is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a method for improving the stability of rice wine. Background Art

[0002] Yellow rice wine is the oldest and unique wine in my country. It is mild, mellow, and nutritious. It is rich in low-molecular substances and trace elements such as sugar, peptides, and amino acids, and is easily digested and absorbed by the human body. It is a health wine, a side dish, and a cooking wine that is deeply loved by Chinese consumers. However, after sterilization and filling, and during storage, yellow rice wine will lose its gloss, become turbid, and even precipitate, which seriously affects the quality of yellow rice wine and has become a key core issue restricting the development of the yellow rice wine industry. In particular, in some bottled yellow rice wines, the appearance of turbidity / precipitation has become the main reason for consumers to return yellow rice wine during its shelf life. Studies have shown that the main reason for the stability problem of yellow rice wine is that yellow rice wine contains high concentrations of proteins, polyphenols, polysaccharides, and minerals. These components are prone to interact with each other during long-term storage, forming precipitation or flocculation. In addition, external factors such as temperature, pH changes, and alcohol concentration will also accelerate the physical and chemical changes of yellow rice wine, further reducing its stability. At present, there have been studies that attempt to reduce the precipitation problem during the storage of rice wine by optimizing the rice wine clarification process and developing new treatment devices to improve its stability. Patent CN 200710131813.4 discloses a method for improving the stability of rice wine. The method uses the addition of a composite clarifier, combined with freezing and ultrafiltration treatment to effectively remove substances that cause rice wine turbidity and precipitation, improve the stability of rice wine and maintain its sensory quality. However, the process involved in this method is complex and the production cost is high, which limits its practical application. Patent CN 202010696020.2 discloses a clarification treatment method for aged rice wine. This method not only improves the quality of rice wine by adding a composite clarifier, dealcoholization treatment and high-pressure treatment, but also significantly improves the stability. However, its technical solution has high energy consumption, increases industrial production costs, and has a certain impact on the environment. Patent CN 201110273250.9 discloses a rice wine clarification device, which accelerates precipitation by freezing before filtration, and then filters the rice wine, thereby improving the stability of the rice wine and ensuring its quality and market sales. However, this method involves expensive equipment and production line changes, which is costly. Therefore, in order to solve the above technical problems, a new technical solution needs to be proposed to solve the problem, especially to provide a method with low cost, simple operation and the ability to effectively remove the key substances that form precipitation. Summary of the invention

[0003] Technical problem to be solved: In view of the above technical problems, the purpose of the present invention is to provide a method for improving the stability of rice wine, a composite gel containing ball-milled / esterified carrageenan solution and sodium alginate gel with fixed complex enzyme is prepared, the composite gel is put into rice wine, and the supernatant is taken by centrifugation to obtain rice wine with high stability and high clarity. The invention prepares a composite gel containing a ball-milled / esterified carrageenan solution and a sodium alginate gel with a fixed composite enzyme. The esterified carrageenan can increase the stability of yellow wine and reduce the precipitation of protein and other solids. The ball-milled esterified carrageenan is endowed with interface adsorption, thereby improving the clarity of the yellow wine. Pectinase can decompose pectin, and galactosidase can decompose lactose and other galactosides in the raw materials. By decomposing these substances, the galactosidase can increase the content of fermentable sugar, reduce the turbidity of the wine body, promote the clarification of the yellow wine, and improve the stability of the yellow wine. Both the pectinase and the galactosidase can increase the content of fermentable sugar through different pathways, provide more nutrients for yeast, and promote the growth and fermentation of yeast. The ball-milled / esterified carrageenan and the sodium alginate gel with the fixed composite enzyme can form a stable system, so that small particles in the yellow wine are aggregated into larger particles, which is convenient for filtering and clarification.

[0004] Technical solution: A method for improving the stability of rice wine, comprising the following steps: S1. esterifying carrageenan with monoolein, and ball-milling the esterified carrageenan to obtain ball-milled / esterified carrageenan; S2. Preparation of sodium alginate gel for immobilizing pectinase and galactosidase; S3. Add 1 part of ball-milled / esterified carrageenan to 80-90 parts of deionized water, heat in a water bath at 70-80° C. to obtain a ball-milled / esterified carrageenan solution, mix the ball-milled / esterified carrageenan solution with sodium alginate gel immobilizing pectinase and galactosidase, and homogenize at 9000-10000 r / min for 5 min to obtain a composite gel; S4. The composite gel was placed in rice wine and stirred at 300-600r / min for 10-20min; ultrasonic-assisted dispersion was performed at 200-300W and 20-40kHz for 5-10min; microwave treatment was performed at 200-500W for 3-5min; S5. Place the rice wine in the composite gel in a double-layer temperature-controlled storage tank, fill it with nitrogen with a purity of ≥99.99%, add timed dynamic disturbance during the static process, use a micro-vibration device for 10-15 minutes every 6-8 hours, and use an electrostatic field auxiliary device to apply a uniform electric field every 10-12 hours for 30-40 minutes to accelerate precipitation. After the static process is completed, transfer the rice wine to a centrifuge for separation and collect the supernatant obtained by centrifugation. Furthermore, the specific preparation method of ball-milling / monoolein esterified carrageenan in step S1 comprises the following steps, in parts by weight: S11. Weigh 1 part of carrageenan and add it to 90-100 parts of deionized water, heat it in a water bath at 70-80°C, and adjust the pH to 8.0-8.5 with NaOH solution; S12. Slowly add monoolein while stirring, and continue to stir the reaction for 1-2h after addition, during which NaOH solution is continuously added dropwise to maintain the pH value of the entire system at 8.0-8.5; S13. After the reaction, the pH of the system was adjusted to 6.0-6.5 with HCl solution, the excess monoolein was removed by dialysis, and the esterified carrageenan was freeze-dried and stored in a drying oven; S14. 90-100 parts of esterified carrageenan and 900-1000 parts of zirconium oxide balls are mixed, loaded into a ball mill, processed at 350-450 r / min for 2-3 h, respectively, and passed through a 100-mesh sieve to obtain ball-milled / esterified carrageenan. Furthermore, in step S12, the mass ratio of carrageenan to glyceryl monooleate is 1:(1-3). Furthermore, the specific preparation method of the sodium alginate gel for fixing pectinase and galactosidase in step S2 comprises the following steps, in parts by weight: S21. Add 1 part of sodium alginate to 90-100 parts of water and heat in a water bath at 60-65°C to prepare a sodium alginate solution; S22. The pectinase and galactosidase were dissolved in water to prepare 45g / L pectinase solution and 45g / L galactosidase solution, the two enzyme solutions were stirred to prepare a composite enzyme solution; S23. 5-7 parts of the complex enzyme solution and 10-12 parts of the sodium alginate solution are fully mixed and stirred, emulsified for 35-45 minutes, and the mixed solution is dropped into the calcium chloride solution with a syringe, and then allowed to stand for 30-40 minutes to prepare the sodium alginate gel loaded with the complex enzyme solution. Furthermore, in step S22, the volume ratio of the pectinase solution to the galactosidase solution is 2:(3-5). Furthermore, in step S3, the mass ratio of the ball-milled / esterified carrageenan solution to the sodium alginate gel immobilizing the complex enzyme is 1:(3-5). Furthermore, in step S4, the amount of the composite gel added to the rice wine is 0.1-0.5 g / L. Furthermore, in step S5, the centrifugal conditions are 2500-3000 r / min and the time is 10-15 min. Beneficial effects: 1. The present invention esterifies carrageenan with monoolein. In the process of modifying carrageenan, monoolein reacts with hydroxyl groups in carrageenan to form ester bonds, and the hydrophobic long-chain alkyl of monoolein is introduced. The emulsification stability of the modified carrageenan is improved. The esterified carrageenan can increase the stability of rice wine and reduce the precipitation of proteins and other solids. The esterified carrageenan is ball-milled, and the crystal structure is destroyed by ball milling to give the esterified carrageenan interfacial adsorption, thereby improving the stability and clarity of the rice wine. 2. The present invention prepares sodium alginate gel with fixed pectinase and galactosidase, pectinase can decompose pectin, galactosidase can decompose lactose and other galactosides in the raw materials, and by decomposing these substances, galactosidase can increase the content of fermentable sugar, provide more nutrients for yeast, and promote yeast growth and fermentation. Pectinase can reduce the turbidity of the wine body. Pectinase and galactosidase jointly promote the aggregation and sedimentation of suspended particles, promote the clarification of rice wine, and improve the long-term stability of rice wine. 3. The present invention prepares a composite gel by combining ball-milled / esterified carrageenan and sodium alginate gel with fixed complex enzymes. On the one hand, the ball-milled / esterified carrageenan can flocculate the suspended particles decomposed by pectinase and galactosidase. The joint action of ball-milled / esterified carrageenan, pectinase and galactosidase can reduce the resistance in the filtration process, improve the filtration efficiency and the stability of rice wine, and the ball-milled / esterified carrageenan and sodium alginate can promote the flocculation of suspended particles through charge neutralization and bridging, effectively capture and sink the suspended particles, thereby accelerating the clarification process; on the other hand, the prepared composite gel can protect pectinase and galactosidase from the influence of other components in rice wine, prolong the action time of pectinase and galactosidase, control the slow release of the internal sodium alginate gel with fixed complex enzymes, thereby controlling the action speed of the enzyme and the flocculation effect of carrageenan, avoiding excessive reaction or unnecessary waste caused by one-time release, and improving the stability and clarity of rice wine. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is the light transmittance of the yellow wine not treated with the composite gel and Examples 10-15; Figure 2 The protein content of the rice wine not treated with the composite gel and Examples 10-15; Figure 3 is the polyphenol content of the yellow wine not treated with the composite gel and Examples 10-15; Figure 4 is the total sugar content of the rice wine not treated with the composite gel and Examples 10-15; Figure 5 The particle states of the yellow wine not treated with the composite gel and Examples 10-15; Figure 6 The particle size distribution diagram of the yellow wine not treated with the composite gel and Examples 10-15. DETAILED DESCRIPTION The present invention proposes a method for improving the stability of rice wine. In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention will be further described in detail with reference to the embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1 The specific preparation method of ball milling / monoolein esterified carrageenan, in parts by weight, comprises the following steps: S11. Weigh 1 part of carrageenan and add it to 100 parts of deionized water, heat it in a water bath at 80°C, and adjust the pH to 8.5 with NaOH solution; S12. Slowly add monoolein while stirring, the mass ratio of carrageenan to monoolein is 1:1, and continue to stir and react for 1 hour, during which time the NaOH solution is continuously added dropwise to maintain the pH value of the entire system at 8.5; S13. After the reaction, the pH of the system was adjusted to 6.5 with HCl solution, the excess monoolein was removed by dialysis, and the esterified carrageenan was freeze-dried and stored in a drying oven; S14. 90 parts of esterified carrageenan and 900 parts of zirconium oxide balls were mixed, loaded into a ball mill, processed at 450 r / min for 3 h, and passed through a 100-mesh sieve to obtain ball-milled / esterified carrageenan. Example 2 The specific preparation method of ball milling / monoolein esterified carrageenan, in parts by weight, comprises the following steps: S11. Weigh 1 part of carrageenan and add it to 100 parts of deionized water, heat it in a water bath at 80°C, and adjust the pH to 8.5 with NaOH solution; S12. Slowly add monoolein while stirring, the mass ratio of carrageenan to monoolein is 1:2, and continue to stir and react for 1 hour after adding, during which time the NaOH solution is continuously added dropwise to maintain the pH value of the entire system at 8.5; S13. After the reaction, the pH of the system was adjusted to 6.5 with HCl solution, the excess monoolein was removed by dialysis, and the esterified carrageenan was freeze-dried and stored in a drying oven; S14. 90 parts of esterified carrageenan and 900 parts of zirconium oxide balls were mixed, loaded into a ball mill, processed at 450 r / min for 3 h, and passed through a 100-mesh sieve to obtain ball-milled / esterified carrageenan. Example 3 The specific preparation method of ball milling / monoolein esterified carrageenan, in parts by weight, comprises the following steps: S11. Weigh 1 part of carrageenan and add it to 100 parts of deionized water, heat it in a water bath at 80°C, and adjust the pH to 8.5 with NaOH solution; S12. Slowly add monoolein while stirring, the mass ratio of carrageenan to monoolein is 1:3, and continue to stir and react for 1 hour after adding, during which time the NaOH solution is continuously added dropwise to maintain the pH value of the entire system at 8.5; S13. After the reaction, the pH of the system was adjusted to 6.5 with HCl solution, the excess monoolein was removed by dialysis, and the esterified carrageenan was freeze-dried and stored in a drying oven; S14. 90 parts of esterified carrageenan and 900 parts of zirconium oxide balls were mixed, loaded into a ball mill, processed at 450 r / min for 3 h, and passed through a 100-mesh sieve to obtain ball-milled / esterified carrageenan. Comparative Example 1 The difference between this comparative example and Example 3 is that the carrageenan is not modified by using monoolein. The specific preparation method of ball mill / carrageenan, in parts by weight, comprises the following steps: S11. Weigh 1 part of carrageenan and add it to 100 parts of deionized water, heat it in a water bath at 80°C, and adjust the pH to 8.5 with a NaOH solution; S12. Freeze-dry the carrageenan and store it in a drying oven; S13. Mix 90 parts of carrageenan and 900 parts of zirconium oxide balls, put them into the ball mill, process them at 450 r / min for 3 h, pass them through a 100-mesh sieve, and obtain ball mill / carrageenan. Performance Testing (1) Whiteness measurement The whiteness of the samples prepared in Examples 1-3 and Comparative Example 1 was measured using a whiteness meter. (2) Viscosity measurement One portion of the samples prepared in Examples 1-3 and Comparative Example 1 was dissolved in 90 portions of water, heated in a 60° C. water bath for 30 min, and measured using a digital viscometer after the solution temperature stabilized. (3) Determination of emulsification and emulsion stability Take 1 part of the sample prepared in Examples 1-3 and Comparative Example 1, heat and dissolve it in 90 parts of water, add 10 parts of soybean oil, and perform high-speed shearing at 10000 r / min for 10 minutes at room temperature to obtain an emulsion. Take the emulsion from the bottom of the beaker and mix it with sodium dodecyl sulfate. Use the sodium dodecyl sulfate solution as a blank control, and use an ultraviolet spectrophotometer to measure the initial absorbance value A0 of the emulsion at 500nm. A0 represents the emulsification degree, and ESI represents the emulsification stability: ESI=A0×ΔtΔA Wherein, Δt=20min, ΔA is the difference between the absorbance of the emulsion after 20min and A0. Table 1 Whiteness, viscosity, emulsification and emulsion stability of Examples 1-3 and Comparative Example 1 As can be seen from Table 1, the whiteness of ball-milled / esterified carrageenan is higher than that of ball-milled / carrageenan, and the whiteness of Example 3 is the highest. When carrageenan is added to food, it is generally required that carrageenan should not affect the color of the product. The whiter the color of the carrageenan, the smaller the effect when used, indicating that the use of Example 3 has the smallest effect on the product; the viscosity of ball-milled / esterified carrageenan is lower than that of ball-milled / carrageenan, and the viscosity of Example 3 is the lowest. This is because the molecular weight of carrageenan decreases during the esterification process. After the oleic acid substituent is introduced, some hydrogen bonds of carrageenan are broken, and the intermolecular forces are weakened, thereby decreasing the viscosity. The viscosity increases with the increase of the mass ratio of carrageenan to monoolein; the emulsification and emulsification stability of ball-milled / esterified carrageenan are higher than those of ball-milled / carrageenan, and the emulsification and emulsification stability of Example 3 are the highest. This is because the hydrophobic part of unesterified carrageenan is small and the emulsification capacity is limited. Some hydrophobic groups contained in monoolein are grafted onto the carrageenan molecule to improve the emulsification of carrageenan, and the esterified carrageenan weakens the oil-water interfacial tension, thereby improving the emulsification stability. Therefore, the following examples adopt the method of Example 3 to prepare ball-milled / esterified carrageenan. Example 4 The specific preparation method of sodium alginate gel for fixing pectinase and galactosidase comprises the following steps, calculated by weight: S21. Add 1 part of sodium alginate to 100 parts of water and heat in a water bath at 65°C to prepare a sodium alginate solution; S22. Pectinase and galactosidase were dissolved in water to prepare 45 g / L pectinase solution and 45 g / L galactosidase solution, 2 parts of pectinase solution and 3 parts of galactosidase solution were stirred to prepare a composite enzyme solution; S23. 5 parts of the complex enzyme solution and 10 parts of the sodium alginate solution were fully mixed and stirred, emulsified for 35 minutes, and the mixed solution was dropped into the calcium chloride solution with a syringe, and then allowed to stand for 30 minutes to prepare the sodium alginate gel loaded with the complex enzyme solution. Example 5 The specific preparation method of sodium alginate gel for fixing pectinase and galactosidase comprises the following steps, calculated by weight: S21. Add 1 part of sodium alginate to 100 parts of water and heat in a water bath at 65°C to prepare a sodium alginate solution; S22. The pectinase and galactosidase were dissolved in water to prepare 45g / L pectinase solution and 45g / L galactosidase solution, 2 parts of pectinase solution and 4 parts of galactosidase solution were stirred to prepare a composite enzyme solution; S23. 5 parts of the complex enzyme solution and 10 parts of the sodium alginate solution were fully mixed and stirred, emulsified for 35 minutes, and the mixed solution was dropped into the calcium chloride solution with a syringe, and then allowed to stand for 30 minutes to prepare the sodium alginate gel loaded with the complex enzyme solution. Example 6 The specific preparation method of sodium alginate gel for fixing pectinase and galactosidase comprises the following steps, calculated by weight: S21. Add 1 part of sodium alginate to 100 parts of water and heat in a water bath at 65°C to prepare a sodium alginate solution; S22. Pectinase and galactosidase were dissolved in water to prepare 45 g / L pectinase solution and 45 g / L galactosidase solution, 2 parts of pectinase solution and 5 parts of galactosidase solution were stirred to prepare a composite enzyme solution; S23. 5 parts of the complex enzyme solution and 10 parts of the sodium alginate solution were fully mixed and stirred, emulsified for 35 minutes, and the mixed solution was dropped into the calcium chloride solution with a syringe, and then allowed to stand for 30 minutes to prepare the sodium alginate gel loaded with the complex enzyme solution. Comparative Example 2 The difference between this comparative example and Example 5 is that pectinase was not added. The specific preparation method of sodium alginate gel for fixing β-galactosidase comprises the following steps, measured by weight: S21. Add 1 part of sodium alginate to 100 parts of water and heat in a water bath at 65°C to prepare a sodium alginate solution; S22. The galactosidase was dissolved in water to prepare 45 g / L galactosidase enzyme solution, and the enzyme solution was prepared with 4 parts of galactosidase enzyme solution; S23. 5 parts of enzyme solution and 10 parts of sodium alginate solution were fully mixed and stirred, emulsified for 35 minutes, and the mixed solution was dropped into the calcium chloride solution with a syringe, and then allowed to stand for 30 minutes to prepare the sodium alginate gel for fixing galactosidase. Comparative Example 3 The difference between this comparative example and Example 5 is that no β-galactosidase was added. The specific preparation method of sodium alginate gel for fixing pectinase comprises the following steps, calculated by weight: S21. Add 1 part of sodium alginate to 100 parts of water and heat in a water bath at 65°C to prepare a sodium alginate solution; S22. The pectinase was dissolved in water to prepare 45 g / L pectinase solution, and the enzyme solution was prepared with 2 parts of pectinase solution; S23. 5 parts of enzyme solution and 10 parts of sodium alginate solution were fully mixed and stirred, emulsified for 35 minutes, and the mixed solution was dropped into the calcium chloride solution with a syringe, and then allowed to stand for 30 minutes to prepare the sodium alginate gel with fixed pectinase. Performance Testing (1) Mechanical properties A micro-controlled electronic universal testing machine was used to test the compressive strength of the composite hydrogel. (2) Embedding rate Soak 0.2g of gel in 25mL of distilled water, treat at 37℃ for 12h, grind it, and bathe it in 50℃ water for 3h to completely release pectinase and galactosidase from the gel, centrifuge at 10000r / min for 10min, take the supernatant, and determine the protein content according to the Coomassie Brilliant Blue method. The formula for calculating the lactase encapsulation rate is: In the formula: EE—embedding efficiency, %; Co—theoretical protein content, mg; C—actual protein content, mg. (3) Water absorption Weigh the gel after drying in a vacuum oven and record it as W o Then put the gel into deionized water. After a period of sufficient swelling, take out the gel, use filter paper to absorb the water on the surface of the gel, and weigh it, which is recorded as W1. The calculation formula of water absorption is as follows: Table 2 Compressive strength, embedding rate and water absorption of Examples 4-6 and Comparative Examples 2-3 Compressive strength(Kpa) Embedding rate (%) Water absorption Example 4 103.26 84.2 27.95 Example 5 127.39 89.3 35.62 Example 6 114.47 86.9 32.48 Comparative Example 2 93.15 82.1 21.83 Comparative Example 3 95.10 81.5 23.83 As can be seen from Table 1, the compressive strength, embedding rate and water absorption of Example 5 are the highest, which may be due to the synergistic effect of the two enzymes, pectinase and galactosidase, which strengthen the hydrogen bonds and other non-covalent interactions between the gel molecules, increase the cross-linking points in the gel, and thus improve the mechanical strength of the gel; through the joint action of the two enzymes, pectinase and galactosidase, the network structure of the gel is strengthened, which helps to maintain the stability of the gel during the embedding process, thereby preventing the leakage of the embedded material; the action of the two enzymes, pectinase and galactosidase, increases the hydrophilic groups on the surface of the gel, making the gel easier to absorb water. Therefore, the following examples use the method of Example 5 to prepare sodium alginate gels with fixed pectinase and galactosidase. Example 7 The specific preparation method of the composite gel containing ball-milled / esterified carrageenan solution and sodium alginate gel with immobilized complex enzymes comprises the following steps, calculated by weight: S1. Add 1 part of the ball-milled / esterified carrageenan prepared in Example 3 to 90 parts of deionized water and heat in a water bath at 80° C. to prepare a ball-milled / esterified carrageenan solution; S2. Mix 1 part of ball-milled / esterified carrageenan solution and 3 parts of the composite gel of sodium alginate gel immobilizing the composite enzyme prepared in Example 5, and homogenize at 10000 r / min for 5 min to prepare the composite gel. Example 8 The specific preparation method of the composite gel containing ball-milled / esterified carrageenan solution and sodium alginate gel with immobilized complex enzymes comprises the following steps, calculated by weight: S1. Add 1 part of the ball-milled / esterified carrageenan prepared in Example 3 to 90 parts of deionized water and heat in a water bath at 80° C. to prepare a ball-milled / esterified carrageenan solution; S2. Mix 1 part of ball-milled / esterified carrageenan solution and 4 parts of the composite gel of sodium alginate gel immobilizing the composite enzyme prepared in Example 5, and homogenize at 10000 r / min for 5 min to prepare the composite gel. Example 9 The specific preparation method of the composite gel containing ball-milled / esterified carrageenan solution and sodium alginate gel with immobilized complex enzymes comprises the following steps, calculated by weight: S1. Add 1 part of the ball-milled / esterified carrageenan prepared in Example 3 to 90 parts of deionized water and heat in a water bath at 80° C. to prepare a ball-milled / esterified carrageenan solution; S2. Mix 1 part of ball-milled / esterified carrageenan solution and 5 parts of the composite gel of sodium alginate gel immobilizing the composite enzyme prepared in Example 5, and homogenize at 10000 r / min for 5 min to prepare the composite gel. Comparative Example 4 The difference between this comparative example and Example 8 is that the ball mill / carrageenan prepared in Comparative Example 1 is used. The specific preparation method of the composite gel containing ball milling / carrageenan solution and sodium alginate gel with fixed composite enzyme, in parts by weight, comprises the following steps: S1. Add 1 part of the ball-milled / carrageenan prepared in Comparative Example 1 to 90 parts of deionized water and heat in a water bath at 80° C. to prepare a ball-milled / esterified carrageenan solution; S2. Mix 1 part of ball mill / carrageenan solution and 4 parts of the composite gel of sodium alginate gel with immobilized composite enzyme prepared in Example 5, and homogenize at 10000 r / min for 5 min to prepare the composite gel. Comparative Example 5 The difference between this comparative example and Example 8 is that the sodium alginate gel immobilizing galactosidase prepared in Comparative Example 2 is used. The specific preparation method of the composite gel containing ball-milled / esterified carrageenan solution and sodium alginate gel immobilizing galactosidase, in parts by weight, comprises the following steps: S1. Add 1 part of the ball-milled / esterified carrageenan prepared in Example 3 to 90 parts of deionized water and heat in a water bath at 80° C. to prepare a ball-milled / esterified carrageenan solution; S2. Mix 1 part of ball-milled / esterified carrageenan solution and 4 parts of the composite gel of sodium alginate gel immobilizing galactosidase prepared in Comparative Example 2, and homogenize at 10000 r / min for 5 min to prepare the composite gel. Comparative Example 6 The difference between this comparative example and Example 8 is that the sodium alginate gel with immobilized pectinase prepared in Comparative Example 3 is used. The specific preparation method of the composite gel containing ball-milled / esterified carrageenan solution and sodium alginate gel with immobilized pectinase, in parts by weight, comprises the following steps: S1. Add 1 part of the ball-milled / esterified carrageenan prepared in Example 3 to 90 parts of deionized water and heat in a water bath at 80° C. to prepare a ball-milled / esterified carrageenan solution; S2. Mix 1 part of ball-milled / esterified carrageenan solution and 4 parts of the composite gel of sodium alginate gel with immobilized pectinase prepared in Comparative Example 2, and homogenize at 10000 r / min for 5 min to prepare a composite gel. Performance Testing The test methods for compressive strength, embedding rate and water absorption are as described above. Table 3 Compressive strength, embedding rate and water absorption of Examples 7-9 and Comparative Examples 4-6 As can be seen from Table 3, Example 8 has the highest compressive strength, embedding rate and water absorption. This may be because the sulfate groups of ball-milled / esterified carrageenan can cross-link with the carboxyl groups of sodium alginate gel to form a more stable gel structure, thereby improving the compressive strength and embedding rate of the composite gel; esterified / ball-milled carrageenan increases the hydrophilic groups in the gel, making the gel easier to absorb water; pectinase and galactosidase change the chemical properties of the gel surface, making it more hydrophilic, thereby improving the water absorption of the composite gel. Therefore, the following examples adopt the method of Example 8 to prepare a composite gel containing a ball-milled / esterified carrageenan solution and a sodium alginate gel with immobilized complex enzymes. Example 10 A method for improving the stability of yellow rice wine comprises the following steps: S1. A composite gel containing a ball-milled / esterified carrageenan solution and a sodium alginate gel immobilized with a composite enzyme was prepared by the method of Example 8; S2. 0.1 g of the composite gel was placed in 1 L of rice wine, stirred at 600 r / min for 20 min; ultrasonic-assisted dispersion treatment was performed at 300 W and 40 kHz for 10 min; microwave treatment was performed at 500 W for 5 min; S3. Place the rice wine in the composite gel in a double-layer temperature-controlled storage tank, fill it with nitrogen with a purity of ≥99.99%, add timed dynamic disturbance during the static process, use a micro-vibration device for 10 minutes every 6 hours, and use an electrostatic field auxiliary device to apply a uniform electric field every 12 hours for 30 minutes to accelerate precipitation. After the static state is completed, transfer the rice wine to a centrifuge for separation and collect the supernatant obtained by centrifugation. Embodiment 11 A method for improving the stability of yellow rice wine comprises the following steps: S1. A composite gel containing a ball-milled / esterified carrageenan solution and a sodium alginate gel immobilized with a composite enzyme was prepared by the method of Example 8; S2. 0.2 g of the composite gel was placed in 1 L of rice wine, stirred at 600 r / min for 20 min; ultrasonic-assisted dispersion treatment was performed at 300 W and 40 kHz for 10 min; microwave treatment was performed at 500 W for 5 min; S3. Place the rice wine in the composite gel in a double-layer temperature-controlled storage tank, fill it with nitrogen with a purity of ≥99.99%, add timed dynamic disturbance during the static process, use a micro-vibration device for 10 minutes every 6 hours, and use an electrostatic field auxiliary device to apply a uniform electric field every 12 hours for 30 minutes to accelerate precipitation. After the static state is completed, transfer the rice wine to a centrifuge for separation and collect the supernatant obtained by centrifugation. Example 12 A method for improving the stability of yellow rice wine comprises the following steps: S1. A composite gel containing a ball-milled / esterified carrageenan solution and a sodium alginate gel immobilized with a composite enzyme was prepared by the method of Example 8; S2. 0.3 g of the composite gel was placed in 1 L of rice wine, stirred at 600 r / min for 20 min; ultrasonic-assisted dispersion treatment was performed at 300 W and 40 kHz for 10 min; microwave treatment was performed at 500 W for 5 min; S3. Place the rice wine in the composite gel in a double-layer temperature-controlled storage tank, fill it with nitrogen with a purity of ≥99.99%, add timed dynamic disturbance during the static process, use a micro-vibration device for 10 minutes every 6 hours, and use an electrostatic field auxiliary device to apply a uniform electric field every 12 hours for 30 minutes to accelerate precipitation. After the static state is completed, transfer the rice wine to a centrifuge for separation and collect the supernatant obtained by centrifugation. Embodiment 13 A method for improving the stability of yellow rice wine comprises the following steps: S1. A composite gel containing a ball-milled / esterified carrageenan solution and a sodium alginate gel immobilized with a composite enzyme was prepared by the method of Example 8; S2. 0.4 g of the composite gel was placed in 1 L of rice wine, stirred at 600 r / min for 20 min; ultrasonic-assisted dispersion treatment was performed at 300 W and 40 kHz for 10 min; microwave treatment was performed at 500 W for 5 min; S3. Place the rice wine in the composite gel in a double-layer temperature-controlled storage tank, fill it with nitrogen with a purity of ≥99.99%, add timed dynamic disturbance during the static process, use a micro-vibration device for 10 minutes every 6 hours, and use an electrostatic field auxiliary device to apply a uniform electric field every 12 hours for 30 minutes to accelerate precipitation. After the static state is completed, transfer the rice wine to a centrifuge for separation and collect the supernatant obtained by centrifugation. Embodiment 14 A method for improving the stability of yellow rice wine comprises the following steps: S1. A composite gel containing a ball-milled / esterified carrageenan solution and a sodium alginate gel immobilized with a composite enzyme was prepared by the method of Example 8; S2. 0.5 g of the composite gel was placed in 1 L of rice wine, stirred at 600 r / min for 20 min; ultrasonic-assisted dispersion treatment was performed at 300 W and 40 kHz for 10 min; microwave treatment was performed at 500 W for 5 min; S3. Place the rice wine in the composite gel in a double-layer temperature-controlled storage tank, fill it with nitrogen with a purity of ≥99.99%, add timed dynamic disturbance during the static process, use a micro-vibration device for 10 minutes every 6 hours, and use an electrostatic field auxiliary device to apply a uniform electric field every 12 hours for 30 minutes to accelerate precipitation. After the static state is completed, transfer the rice wine to a centrifuge for separation and collect the supernatant obtained by centrifugation. Performance Testing (1) Light transmittance The spectrophotometer colorimetric method was used for determination. About 2 mL of the sample was placed in a quartz cuvette, distilled water was used as the reference solution, the wavelength was set to 750 nm, and the transmittance of different samples at this wavelength was measured and expressed as T (%). (2) Protein content The protein content is tested according to the national standard GB5009.5-2016. (3) Total phenol content The total phenolic content was determined using the Folin-phenol method and the results were calculated as gallic acid. (4) Total sugar content The total sugar content was determined using the phenol-sulfuric acid method, and the results were calculated as glucose. (5) Particle state and particle size (6) Turbidity of wine sample: On a visible spectrophotometer, set 800 nm as the measurement wavelength, use a clear wine sample without gel as a reference, quickly shake the wine sample to be measured and measure the transmittance T. The turbidity of rice wine is 1-T. (7) Wine sample strengthening experiment: Place the wine sample in a refrigerator at 0℃~4℃ for 12 hours and in an oven at 60℃ for 12 hours. After two cycles, take out the sample and quickly measure the transmittance T at 800nm ​​at room temperature. The turbidity is 1-T. (8) Ethanol turbidity determination: Add 7.5 mL of anhydrous ethanol to 15 mL of wine sample, shake with a mixer for 1 min, leave at room temperature for 2 h, and quickly measure its turbidity after taking out. The particle state of the rice wine of different embodiments was observed using an optical microscope at 40X, 100X, and 400X magnifications, and the particle size distribution of different embodiments was measured using a nanoparticle size analyzer. Table 4 Stability test of Examples 10-14 Wine turbidity Turbidity after strengthening Ethanol turbidity determination Example 10 0.039 0.345 0.356 Embodiment 11 0.034 0.309 0.347 Example 12 0.036 0.331 0.351 Example 13 0.037 0.342 0.353 Embodiment 14 0.041 0.351 0.360 As can be seen from Table 4, the wine sample of Example 11 showed little turbidity after treatment and had the best stability. from Figure 1 It can be seen that the light transmittance of the rice wine not treated with sodium alginate and carrageenan is significantly lower than that of the examples, among which Example 11 has the most significant effect, with a light transmittance of 97.7% and the best clarification effect; Figure 2 It can be seen that after the composite gel treatment, the protein content of the main substance forming the precipitate in the rice wine decreased significantly, among which the effect of Example 11 was the most significant, with the protein content reduced to 0.66 mg / mL, which was 43.1% lower than that of the original wine; Figure 3 It can be seen that after the composite gel treatment, the polyphenol content in the rice wine decreased, and the elimination rate was as high as 19.5%. This is because the composite gel has a good adsorption effect on the polyphenols in the rice wine, thereby reducing the chance of polyphenols combining with proteins and achieving a clarification effect; Figure 4 It can be seen that the total sugar content of rice wine increases with the increase of the content of composite gel. This is because the composite gel will combine with other substances to remove turbid particles, and the removal rate is as high as 33.1%. Figure 5 It can be seen that after the rice wine was treated with composite gel, the particle density was significantly reduced, and more impurity particles were precipitated and removed; Figure 6 It can be seen that after the rice wine is treated with the composite gel, the particle size is significantly reduced, and the particle size of Example 11 is the smallest. comprehensive Figure 1-6 As shown in Table 4, the rice wine in the embodiment has the best clarity and stability, which may be because the esterified carrageenan can increase the stability of the rice wine, reduce the precipitation of protein and other solids, and the esterified carrageenan is ball-milled, and the ball milling destroys the crystal structure to give the esterified carrageenan interfacial adsorption, thereby improving the stability and clarity of the rice wine; pectinase and galactosidase jointly promote the aggregation and sedimentation of suspended particles, thereby promoting the clarification of the rice wine; the prepared composite gel can control the slow release of the sodium alginate gel that fixes the composite enzyme inside, thereby improving the stability of the rice wine. The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for improving the stability of rice wine, characterized in that: The following steps are involved: S1. esterifying carrageenan with monoolein, and ball-milling the esterified carrageenan to obtain ball-milled / esterified carrageenan; S2. Preparation of sodium alginate gel for immobilizing pectinase and galactosidase; S3. Add 1 part of ball-milled / esterified carrageenan to 80-90 parts of deionized water, heat in a water bath at 70-80° C. to obtain a ball-milled / esterified carrageenan solution, mix the ball-milled / esterified carrageenan solution with sodium alginate gel immobilizing pectinase and galactosidase, and homogenize at 9000-10000 r / min for 5 min to obtain a composite gel; S4. The composite gel was placed in rice wine and stirred at 300-600r / min for 10-20min; ultrasonic-assisted dispersion was performed at 200-300W and 20-40kHz for 5-10min; microwave treatment was performed at 200-500W for 3-5min; S5. Place the rice wine in the composite gel in a double-layer temperature-controlled storage tank, fill it with nitrogen with a purity of ≥99.99%, add timed dynamic disturbance during the static process, use a micro-vibration device for 10-15 minutes every 6-8 hours, and use an electrostatic field auxiliary device to apply a uniform electric field every 10-12 hours for 30-40 minutes to accelerate precipitation. After the static process is completed, transfer the rice wine to a centrifuge for separation and collect the supernatant obtained by centrifugation.

2. A method for improving the stability of rice wine according to claim 1, characterized in that: The specific preparation method of ball-milling / monoolein esterified carrageenan in step S1 comprises the following steps, in parts by weight: S11. Weigh 1 part of carrageenan and add it to 90-100 parts of deionized water, heat it in a water bath at 70-80°C, and adjust the pH to 8.0-8.5 with NaOH solution; S12. Slowly add monoolein while stirring, and continue to stir the reaction for 1-2h after addition, during which NaOH solution is continuously added dropwise to maintain the pH value of the entire system at 8.0-8.5; S13. After the reaction, the pH of the system was adjusted to 6.0-6.5 with HCl solution, the excess monoolein was removed by dialysis, and the esterified carrageenan was freeze-dried and stored in a drying oven; S14. 90-100 parts of esterified carrageenan and 900-1000 parts of zirconium oxide balls are mixed, loaded into a ball mill, processed at 350-450 r / min for 2-3 h, respectively, and passed through a 100-mesh sieve to obtain ball-milled / esterified carrageenan.

3. A method for improving the stability of rice wine according to claim 2, characterized in that: In step S12, the mass ratio of carrageenan to glyceryl monooleate is 1:(1-3).

4. The method for improving the stability of rice wine according to claim 1, characterized in that: The specific preparation method of the sodium alginate gel for fixing pectinase and galactosidase in step S2 comprises the following steps, in parts by weight: S21. Add 1 part of sodium alginate to 90-100 parts of water and heat in a water bath at 60-65°C to prepare a sodium alginate solution; S22. The pectinase and galactosidase were dissolved in water to prepare 45g / L pectinase solution and 45g / L galactosidase solution, the two enzyme solutions were stirred to prepare a composite enzyme solution; S23. 5-7 parts of the complex enzyme solution and 10-12 parts of the sodium alginate solution are fully mixed and stirred, emulsified for 35-45 minutes, and the mixed solution is dropped into the calcium chloride solution with a syringe, and then allowed to stand for 30-40 minutes to prepare the sodium alginate gel loaded with the complex enzyme solution.

5. A method for improving the stability of rice wine according to claim 4, characterized in that: In the step S22, the volume ratio of the pectinase solution to the galactosidase solution is 2:(3-5).

6. A method for improving the stability of rice wine according to claim 1, characterized in that: In the step S3, the mass ratio of the ball-milled / esterified carrageenan solution to the sodium alginate gel immobilizing the complex enzyme is 1:(3-5).

7. A method for improving the stability of rice wine according to claim 1, characterized in that: In step S4, the amount of the composite gel added to the rice wine is 0.1-0.5 g / L.

8. The method for improving the stability of rice wine according to claim 1, characterized in that: The centrifugal conditions in step S5 are 2500-3000 r / min and the time is 10-15 min.

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