Yeast hydrolysate and application thereof

Abstract

The invention relates to the technical field of biology, in particular to yeast hydrolysate and application thereof. According to the method, enzymes are reasonably screened, the obtained compound enzyme can conduct enzymolysis on yeast strains more effectively, so that hydrolysate rich in free-state lipid, amino acid, polysaccharide and other substances is prepared, the hydrolysate is more beneficial to growth and utilization of yeast, the health state of active yeast cell membranes is improved, and yeast fermentation is promoted.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, and more particularly to yeast hydrolysates and their applications. Background Technology

[0002] Yeast fermentation refers to the process by which yeast converts sugar into ethanol. During this process, yeast requires nutrients such as nitrogen, vitamins, lipids, and minerals to ensure its growth and fermentation. In fruit wine production, especially in grape winemaking, the yeast's fermentation capacity is closely related to the quality of the resulting fruit wine.

[0003] Studies have shown that yeast fermentation capacity is significantly affected by the composition of the fermentation substrate. For example, in wine fermentation, nitrogen is an important nutrient, and yeast biomass is directly related to the available nitrogen in grape juice. Yeast biomass controls the fermentation rate and the synthesis of volatile compounds. However, nitrogen content in grape juice is limited, and the lack of nitrogenous nutrients is the most common cause of fermentation stagnation and slow fermentation. Yeast-assimilated nitrogen (YAN) in grape juice is mainly composed of ammonium ions and α-amino acids. It is generally believed that the minimum amount of yeast-assimilated nitrogen required to ferment 200 g / L of sugar is 140 mg / L, and the optimal amount is about 300 mg / L. With climate change, the sugar content in grapes is constantly increasing, sometimes even reaching over 280 g / L, causing yeast to require more nutrients to complete fermentation. The nutrients in grapes cannot meet the yeast's needs for fermentation.

[0004] Lipids, including sterols and long-chain fatty acids, are also key nutrients in alcoholic fermentation. Yeast requires oxygen to synthesize sterols and long-chain fatty acids. Insufficient long-chain fatty acids or sterols negatively impact fermentation. White wine production uses clarified grape juice, and the clarification process leads to insufficient lipid content in the juice, resulting in reduced yeast activity and affecting fermentation. Studies have shown that under nitrogen-dependent conditions, lipid deficiency in grape juice leads to incomplete fermentation. Furthermore, during wine fermentation, yeast metabolism produces ethanol and medium-chain fatty acids (such as caproic acid, caprylic acid, and capric acid), which inhibit yeast metabolism and growth. The effect of ethanol on yeast growth and fermentation efficiency is mainly reflected in changes in membrane permeability and fluidity. In addition, lipids affect yeast cell signaling, energy supply, and cell activity, and are crucial for maintaining cell structure. Especially after ethanol production begins during fermentation, the biosynthesis and activity of the yeast cell membrane are affected by the lipid nutrient content under anaerobic fermentation and growth conditions. Increasing lipid content is crucial for the activity, membrane integrity, H-ATPase function, and ethanol tolerance of Saccharomyces cerevisiae.

[0005] Some have attempted to improve fermentation by adding yeast hydrolysate. Yeast hydrolysate contains nutrients such as amino acids, lipids, minerals, and vitamins. After processes like cell wall disruption, enzymatic hydrolysis, and autolysis, it releases these nutrients, providing the yeast with these essential nutrients. However, current yeast hydrolysates suffer from an imbalanced nutritional composition. Specifically, lipids and sterols in the yeast products often exist in a bound state within the yeast cell membrane, unable to be absorbed and metabolized by the yeast. In a fermentation environment lacking lipids, this provides little effective solution, resulting in poor fermentation improvement. Yeast fermentation performance and metabolism are closely related to the quality of the wine; incomplete fermentation leads to substandard final product quality, causing significant economic losses to the industry. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to release the yeast hydrolysate from the yeast by a compound enzyme to promote yeast growth, and to apply it in fruit wine.

[0007] This invention screened endopeptides and exopeptides based on their functions. Among various proteases, including pepsin, trypsin, papain, bromelain, subtilisin, neutral protease, alkaline protease, and acidic protease, screening revealed that alkaline protease can better cooperate with enzyme B, disrupting the yeast cell wall. The enzymatic hydrolysate releases more lipids, thus better assisting yeast fermentation. Therefore, in this invention, enzyme A in the complex enzyme is an alkaline protease.

[0008] Based on this, the present invention screens and combines various enzymes, for example, using one or more of mannanase, β-glucanase, cellulase, and lipase for enzymatic hydrolysis. Lipases include carboxylesterases, phospholipases, and carboxyl ester hydrolases, which can progressively hydrolyze triglycerides into glycerol and fatty acids, including phospholipases, sterolases, and carboxylesterases. Phospholipases are a class of enzymes present in organisms that can hydrolyze glycerophospholipids, including phospholipases A1, A2, B, C, and D. They specifically act on various ester bonds within the phospholipid molecule to form different enzymatic hydrolysis products.

[0009] The results showed that the combination of glucanase and phospholipase had a more reasonable recognition site, where the phospholipase could be phospholipase A1 and / or phospholipase A2 and / or lysophospholipase. The hydrolysate obtained from this enzymatic hydrolysis could more effectively assist yeast fermentation. Furthermore, adding nuclease could further improve the enzymatic hydrolysis effect and release nucleic acids. The obtained hydrolysate exhibited higher fermentation speed and quality during fermentation. In this invention, enzyme B is composed of glucanase, phospholipase A1, phospholipase A2, lysophospholipase, and nuclease, wherein the mass ratio of glucanase, phospholipase A1, phospholipase A2, lysophospholipase, and nuclease is (0.1~0.5):(0.1~0.5):(0~0.5):(0~0.5):(0~0.5).

[0010] As a feasible example, the enzyme B is composed of glucanase, phospholipase A1 and lysophospholipase, wherein the mass ratio of glucanase, phospholipase A1 and lysophospholipase is (0.1~0.5):(0.1~0.5):(0.1~0.5).

[0011] As a feasible example, the enzyme B is composed of glucanase, phospholipase A1, lysophospholipase and nuclease, wherein the mass ratio of glucanase, phospholipase A1, lysophospholipase and nuclease is (0.1~0.5):(0.1~0.5):(0.1~0.5):(0.1~0.5).

[0012] As a feasible example, the enzyme B is composed of glucanase, phospholipase A1, lysophospholipase and phospholipase A2, wherein the mass ratio of glucanase, phospholipase A1, lysophospholipase and phospholipase A2 is (0.1~0.5):(0.1~0.5):(0.1~0.5):(0.1~0.5).

[0013] In some embodiments, the mass ratio of enzyme A to enzyme B is 0.3:(0.3~1.5).

[0014] In some specific embodiments, enzyme B is composed of glucanase, phospholipase A1 and lysophospholipase, wherein the mass ratio of glucanase, phospholipase A1 and lysophospholipase is 0.3:0.3:0.3.

[0015] In other specific embodiments, enzyme B is composed of glucanase, phospholipase A1, lysophospholipase and nuclease, wherein the mass ratio of glucanase, phospholipase A1, lysophospholipase and nuclease is 0.3:0.3:0.3:0.3.

[0016] In other specific embodiments, enzyme B is composed of glucanase, phospholipase A1, lysophospholipase and phospholipase A2, wherein the mass ratio of glucanase, phospholipase A1, lysophospholipase and phospholipase A2 is 0.3:0.3:0.3:0.3.

[0017] The composite enzyme provided by this invention can release lipids and polysaccharides in yeast, releasing bound lipids and releasing polysaccharides using glucanase, thereby increasing the contact area on the cell wall.

[0018] Furthermore, the present invention provides a method for preparing yeast hydrolysate, which includes hydrolyzing yeast milk with enzyme A in the aforementioned complex enzyme, followed by hydrolysis with enzyme B to obtain the product.

[0019] In this invention, the preparation of the yeast milk includes culturing activated yeast. The yeast milk contains 8% to 20% yeast by mass. In a specific embodiment, the yeast by mass is 13% to 18%, for example, 13% or 18%. In this embodiment, the protein content is 30% to 60%, specifically 37.5% to 58.5%, for example, 37.5% or 40%.

[0020] In this invention, the yeast is a yeast belonging to the genus *Saccharomyces* or non-*Saccharomyces*, such as baker's yeast, wine yeast, and brewer's yeast. Preferably, the yeast belongs to the genus *Saccharomyces*, *Torulaspora*, *Kluyveromyces*, or *Candida*, more preferably to *Saccharomyces cerevisiae*, specifically *Saccharomyces cerevisiae* FX-2, with the Latin name *Saccharomyces cerevisiae* FX-2 and the accession number CCTCC NO: M2016418.

[0021] In this invention,

[0022] The conditions for enzyme A hydrolysis include: pH value of 7.0~10.5, hydrolysis at 30~70℃ for 2~8 hours; preferably, the conditions for enzyme A hydrolysis include: pH value of 9.0~9.5, hydrolysis at 55℃ for 3~5 hours.

[0023] The conditions for enzyme B hydrolysis include: pH value of 3.0~6.0, hydrolysis at 30~70℃ for 5~10h; preferably, the conditions for enzyme B hydrolysis include: pH value of 5.0, hydrolysis at 55℃ for 8~10h.

[0024] In this invention, after enzymatic hydrolysis, the process further includes a step of high-temperature enzyme inactivation followed by spray drying.

[0025] In some embodiments, the temperature for high-temperature enzyme inactivation is not lower than 85°C, for example, 90°C, 95°C, 98°C, 100°C or 120°C.

[0026] In some embodiments, after enzyme inactivation, the product is sequentially evaporated, concentrated, and dried to obtain yeast hydrolysate. The drying method is one of spray drying, vacuum drying, or drum drying. Preferably, spray drying can ensure the activity of the active substances in the product while obtaining them as quickly as possible.

[0027] Furthermore, the present invention also provides a yeast hydrolysate prepared by the preparation method described above.

[0028] The novel yeast hydrolysate preparation method provided by this invention is rich in free lipids, amino acids, mannans, small peptides, etc., releases polysaccharides from the yeast cell wall, alters the cell wall structure, and increases the adsorption capacity of the cell surface for harmful medium-chain fatty acids released by yeast. Therefore, the obtained yeast hydrolysate, when applied to alcoholic fermentation, can provide balanced nutrients to the yeast during fermentation, alleviate environmental stress on the yeast through adsorption, and promote yeast fermentation.

[0029] Furthermore, the present invention also provides a fruit wine fermentation agent comprising *Saccharomyces cerevisiae* and yeast hydrolysate. In a specific embodiment, the *Saccharomyces cerevisiae* in the fruit wine fermentation agent is *Angelica cerevisiae* CECA, and the mass ratio of the *Saccharomyces cerevisiae* to the yeast hydrolysate is (1~1.5):(1~3). Preferably, the mass ratio of the *Saccharomyces cerevisiae* to the yeast hydrolysate is 1:1.5.

[0030] As a feasible example, the fermentation agent may also include glucose, sucrose, or pectinase. It may also include potassium metabisulfite, lactic acid bacteria, and a clarifying agent.

[0031] Furthermore, the present invention also provides a method for preparing fruit wine, which includes mixing the yeast hydrolysate as described above with fruit juice, inoculating with brewing yeast, and then fermenting.

[0032] In this invention, 150 mg to 600 mg of the yeast hydrolysate is added per liter of fruit juice.

[0033] In a specific embodiment, 250 mg of the yeast hydrolysate is added per liter of juice. Alternatively, 300 mg of the yeast hydrolysate is added per liter of juice. Alternatively, 350 mg of the yeast hydrolysate is added per liter of juice.

[0034] In a specific embodiment, the fermentation conditions include a yeast inoculum concentration of 150 mg / L to 300 mg / L. Preferably, the yeast inoculum concentration is 200 mg / L.

[0035] In a specific embodiment, the juice is grape juice, with a nitrogen content of 216 mg / L and a sugar content of 250 g / L. As a feasibility example, Cabernet Sauvignon grapes were used as the fermentation material.

[0036] In addition, yeast hydrolysates, as mentioned above, can be used in the alcoholic fermentation of various fruit wines, such as the fermentation of at least one of the following fruits: apple, grape, strawberry, bayberry, lychee, banana, pear, citrus, cherry, blueberry, or mulberry.

[0037] This invention, through the rational screening of enzymes, obtains a composite enzyme that can more effectively hydrolyze yeast strains to produce hydrolysates rich in free lipids, amino acids, and polysaccharides. These hydrolysates are more conducive to yeast growth and utilization, improve the health of active yeast cell membranes, and promote yeast fermentation. Attached Figure Description

[0038] Figure 1 This demonstrates the rate of yeast alcoholic fermentation in simulated grape juice.

[0039] Figure 2 Indicates the rate of yeast alcoholic fermentation of grape juice;

[0040] Figure 3 This indicates the content of chain fatty acids in the wine after fermentation;

[0041] Figure 4 This indicates the content of higher alcohols in the wine after fermentation. Detailed Implementation

[0042] This invention provides yeast hydrolysate and its applications. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to implement and apply the technology of this invention.

[0043] The test materials used in this invention are all common commercial products and can be purchased on the market.

[0044] in,

[0045] The preparation of yeast milk for preparing yeast hydrolysate includes: seed culture, primary fermentation culture, and secondary fermentation culture. The fermentation temperature is 20-35℃, and the pH is 4.0-6.0. C, N, P, minerals, vitamins, and other substances are provided according to the specific growth rate of the yeast using a fed-batch method to obtain yeast milk with a protein content of 30%-60% (mass fraction of protein in dry matter). In the specific examples, the yeast milk used is from Angel Yeast Co., Ltd. Saccharomyces cerevisiae FX-2CCTCC NO:M2016418 was deposited at the China Center for Type Culture Collection (Wuhan University) on August 1, 2016.

[0046] The alkaline protease is from Angel Yeast Co., Ltd.

[0047] The glucanase is from Angel Yeast Co., Ltd.

[0048] Phospholipase A1 source: Novozymes.

[0049] Phospholipase A2 is from Angel Yeast Co., Ltd.

[0050] Lysophospholipase is from: Xiasheng Enzyme Biotechnology Co., Ltd.

[0051] The nuclease was sourced from Angel Yeast Co., Ltd.

[0052] The present invention will be further illustrated below with reference to the embodiments:

[0053] Example 1 Preparation of yeast hydrolysate

[0054] Yeast milk containing *Saccharomyces cerevisiae* with a dry matter content of 18 wt% and a protein content of 37.5 wt% was prepared. The pH was adjusted to 9.0, the temperature was adjusted to 55°C, and 0.3 wt% alkaline protease was added. The mixture was treated for 4 h, and the pH was adjusted to 5.0 by adding acid. Then, 0.3 wt% glucanase, 0.3 wt% phospholipase A1, and 0.3 wt% lysophospholipase were added, and the mixture was treated at 55°C for 8 h. The enzyme activity was then inactivated by raising the temperature to 90°C, and the mixture was then spray-dried.

[0055] Example 2 Preparation of yeast hydrolysate

[0056] Yeast milk from brewer's yeast, with a dry matter content of 13 wt% and a protein content of 40 wt%, was prepared. The pH was adjusted to 9.5, the temperature was set at 55℃, and 0.3 wt% alkaline protease was added. The treatment lasted for 4 h. The pH was then adjusted to 5.0 with acid, followed by the addition of 0.3 wt% dextranase, 0.3 wt% phospholipase A1, 0.3 wt% lysophospholipase, and 0.3 wt% nuclease. The treatment was continued at 55℃ for 9 h, followed by temperature increase to 90℃ to inactivate the enzymes, and then spray-dried.

[0057] Example 3 Preparation of yeast hydrolysate

[0058] Yeast milk from brewer's yeast, with a dry matter content of 16 wt% and a protein content of 45 wt%, was prepared by adjusting the pH to 10 and the temperature to 55°C. Alkaline protease (0.3 wt%) was added, and the mixture was treated for 4 hours. The pH was then adjusted to 5.0 by adding acid. Next, 0.3 wt% each of dextranase, phospholipase A1, lysophospholipase, and phospholipase A2 were added, and the mixture was treated at 55°C for 9 hours. The enzyme activity was then inactivated by raising the temperature to 90°C, followed by spray drying.

[0059] Example 4 Preparation of yeast hydrolysate

[0060] Yeast milk from brewer's yeast, with a dry matter content of 15 wt% and a protein content of 58.5 wt%, was prepared by adjusting the pH to 9.5 and the temperature to 55°C. Alkaline protease (0.4 wt%) was added, and the mixture was treated for 4 hours. The pH was then adjusted to 5.0 by adding acid. Next, 0.3 wt% dextranase, 0.3 wt% phospholipase A1, 0.3 wt% lysophospholipase, and 0.3 wt% phospholipase A2 were added, and the mixture was treated at 55°C for 9 hours. The enzyme activity was then inactivated by raising the temperature to 90°C, followed by spray drying.

[0061] Comparative Example 1: Preparation of Yeast Hydrolysate

[0062] Yeast milk of brewer's yeast, with a dry matter mass fraction of 16% and a protein mass fraction of 37% in the dry matter, was treated at pH 10 and temperature 55℃ for 4 h. Then, acid was added to adjust the pH to 5.0, and the temperature was increased to 40℃ for 9 h. Finally, the temperature was raised to 90℃ and spray-dried.

[0063] Comparative Example 2: Preparation of Yeast Hydrolysate

[0064] Yeast milk of brewer's yeast, with a dry matter mass fraction of 16% and a protein mass fraction of 40% in the dry matter, was treated with pH adjusted to 10, temperature adjusted to 55℃, 0.3% alkaline protease added, and treated for 4 h. Then, acid was added to adjust the pH to 5.0, temperature was adjusted to 40℃, and treated for 9 h. Finally, the temperature was raised to 90℃ and spray-dried.

[0065] Experimental Example 1

[0066] The yeast hydrolysates described in Examples 1-4 and Comparative Examples 1-2 were tested, and the results are shown in Table 1:

[0067] Table 1 Results of yeast hydrolysate detection

[0068]

[0069] As can be seen, the hydrolysates prepared in Examples 1-4 of this invention have a solubility of >60%, protein content >30%, amino acid nitrogen content >1%, and free lipid content >0.1%. However, the hydrolysates in Comparative Examples 1-2 have low protein content, poor solubility, and do not contain free lipids.

[0070] Experiment Example 2: Simulated Grape Juice Fermentation

[0071] The effect of fermentation nutrients on wine yeast fermentation was studied using Triple M grape juice simulant. The yeast dosage was 0.2 g / L, and the fermentation nutrient was the yeast hydrolysate prepared in Examples 1, 2, and 3, added at a dosage of 0.3 g / L. The fermentation volume was 500 mL of Triple M grape juice simulant, and the fermentation temperature was 25℃. Yeast CECA was activated and inoculated into 500 mL of grape juice simulant. Carbon dioxide weight loss during fermentation was monitored daily. After fermentation, alcohol, specific gravity, and residual sugar were measured. The fermentation rate was determined based on the residual sugar and alcohol content. A blank control without added yeast hydrolysate was used.

[0072] Table 2. Preparation of Triple M Simulated Grape Juice

[0073]

[0074] Table 3. Composition of YNB Culture Medium

[0075]

[0076] Table 4. Cumulative carbon dioxide loss (g / L) during yeast alcoholic fermentation from day 0 to day 16 ( Figure 1 )

[0077]

[0078] Table 5. Detection indicators after 16 days of fermentation

[0079]

[0080] From Tables 4-5 and Figure 1It can be seen that the yeast hydrolysates obtained in Examples 1 and 2 effectively promoted fermentation, while the yeast hydrolysate obtained in Example 3 had a limited effect on promoting fermentation. Therefore, in the wine fermentation experiment, only the yeast hydrolysates of Examples 1 and 2 were used as the test subjects. All three controls showed significant effects; in winemaking, residual sugar less than 4 g / L indicates complete fermentation.

[0081] Experimental Example 3: Wine Fermentation

[0082] Cabernet Sauvignon grape juice, with yeast assimilated nitrogen content of 216 mg / L and sugar content of 250 g / L, the amount of yeast hydrolysate added in Example 1 or 2 was 300 mg / L, Angel Yeast CECA was inoculated at a yeast inoculation amount of 200 mg / L, and the fermentation temperature was 25℃.

[0083] Table 6. Cumulative weight loss during fermentation (g / L) Figure 2 )

[0084]

[0085] Table 7 Physicochemical properties of wine after fermentation

[0086]

[0087] The fermentation speed and physicochemical indicators after fermentation show that yeast hydrolysate can significantly promote fermentation, resulting in a final sugar content of less than 4g / L in the wine, which meets the quality standards for dry wines. Fermentation is complete, and yeast hydrolysate can also promote the synthesis of glycerol in yeast, which contributes to the sweet and mellow taste of the wine.

[0088] Table 8 Effects on toxic medium-chain fatty acids ( Figure 3 )

[0089]

[0090] The yeast hydrolysate of Examples 1 or 2 helps improve the fatty acid metabolism of yeast, reducing the synthesis of hexanoic acid, caprylic acid, and decanoic acid, thereby reducing the inhibitory effect of these metabolites on yeast growth and fermentation. Compared to Example 2, the yeast hydrolysate of Example 1 is more effective in reducing the content of toxic heavy chain fatty acids.

[0091] Table 9 shows the effect on alcohol aroma ( Figure 4 )

[0092]

[0093] Free amino acids in yeast hydrolysate are effective precursors for improving higher alcohols in wine. These amino acids are metabolized to produce higher alcohols; therefore, the yeast hydrolysates of Examples 1 and 2 significantly promote an increase in higher alcohols in fermented wines. Compared to Example 2, the yeast hydrolysate of Example 1 is more beneficial for improving the metabolism of alcohol aromas.

[0094] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A complex enzyme characterized in that, consisting of enzyme A and enzyme B, the enzyme A is alkaline protease; the enzyme B consists of dextranase, phospholipase A1 and lysophospholipase, wherein the mass ratio of dextranase, phospholipase A1 and lysophospholipase is (0.1-0.5):(0.1-0.5):(0.1-0.5); or the enzyme B consists of dextranase, phospholipase A1, lysophospholipase and nuclease, wherein the mass ratio of dextranase, phospholipase A1, lysophospholipase and nuclease is (0.1-0.5):(0.1-0.5):(0.1-0.5):(0.1-0.5); or the enzyme B consists of dextranase, phospholipase A1, lysophospholipase and phospholipase A2, wherein the mass ratio of dextranase, phospholipase A1, lysophospholipase and phospholipase A2 is (0.1-0.5):(0.1-0.5):(0.1-0.5):(0.1-0.5).

2. The complex enzyme according to claim 1, characterized by, The mass ratio of the enzyme A and the enzyme B is 0.3:(0.3-1.5).

3. The complex enzyme according to claim 1 or 2, characterized in that, the enzyme B consists of dextranase, phospholipase A1 and lysophospholipase, wherein the mass ratio of dextranase, phospholipase A1 and lysophospholipase is 0.3:0.3:0.3; or the enzyme B consists of dextranase, phospholipase A1, lysophospholipase and nuclease, wherein the mass ratio of dextranase, phospholipase A1, lysophospholipase and nuclease is 0.3:0.3:0.3:0.3; or the enzyme B consists of dextranase, phospholipase A1, lysophospholipase and phospholipase A2, wherein the mass ratio of dextranase, phospholipase A1, lysophospholipase and phospholipase A2 is 0.3:0.3:0.3:0.

3.

4. A process for the preparation of a yeast hydrolysate, characterized in that, comprising enzymolysis of the yeast milk by the enzyme A in the complex enzyme according to any one of claims 1-3, and then enzymolysis by the enzyme B.

5. The preparation method according to claim 4, characterized in that, In the yeast milk, the mass fraction of yeast bacteria is 13%-18%, and the mass percentage of protein in dry weight is 30%-60%.

6. The preparation method according to claim 5, characterized in that, The yeast in the yeast milk is one of Saccharomyces cerevisiae or non-Saccharomyces cerevisiae.

7. The preparation method according to claim 4, characterized in that, the enzyme A enzymolysis conditions include pH value of 7.0-10.5, 30-70℃ enzymolysis for 2-8h; the enzyme B enzymolysis conditions include pH value of 3.0-6.0, 30-70℃ enzymolysis for 5-10h.

8. The preparation method according to claim 7, characterized in that, the enzyme A enzymolysis conditions include pH value of 9.0-9.5, 55℃ enzymolysis for 3-5h; the enzyme B enzymolysis conditions include pH value of 5.0, 55℃ enzymolysis for 8-10h.

9. The preparation method according to claim 4, characterized in that, After the enzymolysis, a step of powder drying after enzyme inactivation is further included.

10. A yeast hydrolysate characterized in that, prepared by the preparation method according to any one of claims 4-9.

11. A must fermentation starter characterized in that, comprising Saccharomyces cerevisiae and the yeast hydrolysate according to claim 10.

12. The fruit wine fermentation inoculant of claim 11, wherein, The Saccharomyces cerevisiae is Angel yeast CECA, and the mass ratio of the Saccharomyces cerevisiae to the yeast hydrolysate is (1-1.5):(1-3).

13. A method for the preparation of a fruit wine, characterized in that, The method comprises mixing the yeast hydrolysate of claim 10 with fruit juice, inoculating Saccharomyces cerevisiae, and then fermenting.

14. The method of claim 13, wherein, The yeast hydrolysate of claim 10 is added in an amount of 150 mg / L to 600 mg / L, and the Saccharomyces cerevisiae is inoculated in an amount of 150 mg / L to 300 mg / L.

15. The production method according to claim 13 or 14, characterized by, The fruit juice is grape juice.

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