A method for enhancing the flavor of wine using complex yeasts

Abstract

This invention discloses a method for enhancing the flavor of wine using a compound yeast, relating to the field of wine fermentation and flavor improvement technology. The method includes the following steps: preparation of raw grape juice, screening and preparation of suitable yeast strains, addition of auxiliary materials, selection of inoculation method, and control of fermentation conditions. Non-brewing yeast and brewing yeast are inoculated in a specific ratio. Yeast nutrients are obtained through a specific preparation process and added in two stages to maintain yeast activity. After fermentation, a low-temperature stabilization treatment is performed to optimize the wine's flavor. This invention can significantly enhance the fruit, floral, ester, and terpene content of wine, reduce the content of high-alcohol and volatile acid content, and improve taste and structure.

Description

Technical Field

[0001] This invention relates to the field of wine fermentation and flavor improvement technology, and in particular to a method for wine preparation that utilizes compound yeast to enhance flavor. Background Technology

[0002] The unique flavor of wine primarily originates from the metabolic activities of microorganisms during fermentation, with aroma components such as esters, higher alcohols, and terpenes playing a crucial role in sensory experience. However, traditional industrial winemaking uses only a single yeast (Saccharomyces cerevisiae) for fermentation. While this method boasts highly efficient fermentation capabilities, it tends to result in relatively singular aroma components, making it difficult to showcase complex flavor profiles.

[0003] Meanwhile, naturally fermented grape juice also contains a large number of non-Saccharomyces yeasts. In the past, these strains were often regarded as secondary sources of contamination, but recent studies have shown that carefully selected non-Saccharomyces yeasts, such as Metschnikowia pulcherrima, Torulaspora delbrueckii, Hansenula spp., and Lachancea thermotolerans, can have a positive impact on flavor components through metabolic functions.

[0004] For example, Chinese invention patent application CN116855396A discloses a strain of Hanseniaspora uvarum G2 for winemaking, its fermentation agent and its application. The Hanseniaspora uvarum G2 used in the application has the excellent characteristic of high production of β-glucosidase (66.03±2.46U / mL). When applied to winemaking, it can significantly increase the content of esters and alcohols in wine. At the same time, it can also increase the content and variety of terpenes in wine, thereby enhancing the flavor complexity of wine.

[0005] Chinese invention patent CN113502233B discloses a strain of Maggi Mickey yeast and its application in winemaking. A strain of Maggi Mickey yeast was obtained through screening. This strain grows well at a low temperature of 4℃. After inoculating the strain into grape juice for low-temperature fermentation, alcoholic fermentation is carried out using wine yeast to obtain a low-alcohol wine with a rich aroma.

[0006] On the one hand, these strains often possess esterification capabilities and β-glucosidase activity, which can increase the content of substances such as phenethyl acetate, isoamyl alcohol esters, and terpenes (such as β-damascene and linalool), enhance fruit and floral aroma characteristics, and effectively inhibit green flavor compounds (such as C6 alcohols).

[0007] On the other hand, sequential inoculation (first non-Saccharomyces cerevisiae, then Saccharomyces cerevisiae) can achieve a combined effect of controlled alcohol reduction and enhanced aroma. For example, using Maggi Mage or Delbufoss for primary fermentation, followed by inoculation with Saccharomyces cerevisiae, can lower the final alcohol content and increase the contribution of volatile compounds to the overall aroma. This strategy is particularly effective in increasing the concentration of key aroma components such as ethyl acetate, isobutanol, and 3-methyl-1-butanol.

[0008] In addition, different non-brewing yeast strains also have a positive impact on the color and structure of wine. For example, *Delbrechtia delbrueckii* can release mannoproteins, promoting color stability and improving the texture; *Lachansa*, a heat-resistant yeast, can produce lactic acid, replacing malolactic fermentation to soften acidity and enrich the flavor.

[0009] However, non-brewing yeasts have relatively weak fermentation capabilities, which can easily lead to fermentation stagnation. Therefore, using a combined inoculation method is still the mainstream approach for industrial applications.

[0010] In conclusion, the shift from "fermentation yeast alone" to "compound fermentation combining non-brewing yeast and brewing yeast" represents a trend in flavor improvement within the wine industry. This approach not only enhances aroma diversity and structural complexity but also significantly improves product quality through synergistic effects of different strains. Therefore, designing a compound yeast fermentation method that is process-controllable, features highly efficient strain combinations, and is suitable for industrial-scale operation has significant practical implications and market potential. Summary of the Invention

[0011] Based on the problems raised in the background technology mentioned above, this invention proposes a wine preparation method that uses compound yeast to enhance flavor. By screening dominant non-brewing yeasts and compounding them with brewing yeast, the content of flavor substances such as esters, alcohols, acids, and terpenes in wine is increased, thereby improving the aroma complexity and taste structure.

[0012] The present invention adopts the following technical solution:

[0013] A method for preparing wine using a complex yeast to enhance flavor, comprising the following steps by weight:

[0014] A. Raw material preparation: 1000 portions of grape juice;

[0015] B. Screening and preparing strains: 50-200 parts of brewer's yeast; 5-100 parts of non-brewing yeast;

[0016] C. Auxiliary materials:

[0017] Sulfur dioxide (calculated as SO2) 20-100 parts, added after the grape juice in step A is put into the tank;

[0018] Add 5-50 parts of yeast nutrient solution in two separate applications, with the amount added in each application being the same.

[0019] D. Vaccination method:

[0020] The bacterial strains were inoculated using either simultaneous or spaced-out inoculation methods.

[0021] Simultaneous inoculation: Non-saccharifying yeast and brewing yeast are inoculated together in the grape juice at the same mass ratio for fermentation;

[0022] Intermittent inoculation: First, non-sacchariculture yeast is added to the grape juice, and then sacchariculture yeast is added to continue fermentation;

[0023] E. Fermentation conditions:

[0024] Fermentation temperature: 15-25℃;

[0025] Fermentation time: 7-30 days, until the specific gravity of the fermentation liquid is ≤1.000;

[0026] Fermentation broth pH: 3.0-3.8;

[0027] After fermentation, a wine with enhanced flavor from compound yeast is produced;

[0028] The yeast nutrient solution is prepared by reacting L-cysteine ​​salt, phosphate buffer, and limonene.

[0029] Furthermore, the brewing yeast is in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g.

[0030] Furthermore, the non-brewing yeast is in dry powder form with an activity ≥10. 8 CFU / g.

[0031] Furthermore, the non-Saccharomyces cerevisiae is selected from one of Hansenula spp., Metschnikowia pulcherrima, and Lachancea thermotolerans.

[0032] Furthermore, the method for preparing the yeast nutrient includes:

[0033] H1. Reaction steps: Dissolve 8-22 parts by mass of L-cysteine ​​salt in 70-130 parts by mass of phosphate buffer, adjust the pH to 7.2-8.3 to obtain solution A; add 8-22 parts by mass of limonene to solution A, and stir at 130-270 rpm for 2.5-3.5 hours at 38-47℃ to generate cysteine-limonene conjugate to obtain solution B;

[0034] H2. Post-processing steps: The solution B obtained in step H1 is subjected to spray drying. The inlet air temperature of the spray drying process is 145-155℃, and the outlet air temperature is 72-78℃. Yeast nutrients are obtained by adjusting the feed rate and atomization pressure. The atomization pressure is 0.2-0.6MPa.

[0035] Furthermore, the yeast nutrient is added in two stages: the first stage is added immediately upon yeast inoculation, and the second stage is added during the later stages of fermentation, when the grape juice sugar content has reached 36-40 wt%.

[0036] Furthermore, in step D, when simultaneous inoculation is used, the mass ratio of non-Saccharomyces cerevisiae to Saccharomyces cerevisiae is 1:10 to 1:4.

[0037] Furthermore, in step D, when using interval inoculation, first inoculate 5-100 parts of non-sacchariculture yeast, ferment for 48-72 hours, and then inoculate 50-200 parts of sacchariculture yeast.

[0038] Furthermore, step E is carried out in a sealed fermentation tank, with static or light stirring, 1-2 times daily.

[0039] Furthermore, in step E, after fermentation, the resulting wine is cold-stabilized for 3-7 days at 0-4°C.

[0040] The reaction mechanism of this invention:

[0041] Synergistic metabolism and flavor building of complex yeasts: Non-sacchariculture yeasts and sacchariculture yeasts work together. Non-sacchariculture yeasts secrete esterases, glycosidases, etc., to convert grape substances into flavor substances such as esters and free terpenes, producing polyols and organic acids to improve the body of the wine. Sacchariculture yeasts carry out alcoholic fermentation, producing higher alcohols that form the aroma skeleton. The metabolites of non-sacchariculture yeasts and sacchariculture yeasts interact to form a complex aroma network.

[0042] The synergistic effect of thiol-olefin addition reaction on nutritional flavor: Under weakly alkaline conditions, the thiol group of cysteine ​​is converted into a thiol anion, which undergoes a nucleophilic addition reaction with the double bond of limonene to generate a cysteine-limonene conjugate. This conjugate decomposes during fermentation, and the limonene derivative, as a terpene precursor, is converted into monoterpenoids, imparting characteristic flavors to the wine. Simultaneously, the phosphate buffer maintains pH stability.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1. Compared with pure fermentation using a single brewing yeast, this invention significantly increases the total ester content, specific ethyl esters by ≥30%, and terpenes by a significant amount, while maintaining or slightly reducing the levels of higher alcohols such as isoamyl alcohol and isobutanol. The aroma is more complex and layered, the taste is smoother and more delicate, and the finish is longer.

[0045] 2. Significantly enhanced flavor: Through the synergistic fermentation of compound yeast and the decomposition of coupling compounds to generate flavor substances, the content of esters and terpenes in the wine is increased, adding new aroma layers such as floral and tropical fruit aromas, resulting in a fuller taste and a smoother acidity.

[0046] 3. Stable and controllable quality: By precisely controlling the inoculation method, fermentation conditions and the use of additives, the risk of oxidation and the generation of undesirable flavors are reduced, the shelf life of the finished wine is extended by 10-15%, and the flavor can be customized according to the grape variety, realizing the industrialized and stable production of high-quality wines. Detailed Implementation

[0047] The following provides embodiments of the present invention, clearly and completely describing the technical solutions in these embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0048] It should be noted that in the following examples and comparative examples, Hansenula spp. refers to Hansenula yeast, Metschnikowia pulcherrima refers to Metschnikowia pulcherrima, and Lachancea thermotolerans refers to Lachancea thermotolerans. Therefore, only the Chinese names are used.

[0049] Example 1

[0050] A. Raw material preparation: Prepare 1000g of grape juice.

[0051] B. Screening and preparation of strains: Take 50g of Saccharomyces cerevisiae and 5g of non-Saccharomyces cerevisiae, specifically Hansenula polymorpha; the Saccharomyces cerevisiae shall be in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g, non-Saccharomyces cerevisiae in dry powder form, activity ≥10 8 CFU / g.

[0052] C. Auxiliary materials:

[0053] 20g of sulfur dioxide (calculated as SO2) is added after the grape juice in step A is put into the tank;

[0054] The yeast nutrient solution (5g) was prepared as follows: 8g of L-cysteine ​​hydrochloride was dissolved in 70g of phosphate buffer, and the pH was adjusted to 7.2 to obtain solution A. 8g of limonene was added to solution A, and the mixture was stirred at 130 rpm for 2.5 hours at 38℃ to generate a cysteine-limonene conjugate, yielding solution B. Solution B was then spray-dried. The inlet air temperature for this spray drying process was 145℃, and the outlet air temperature was 72℃. The yeast nutrient solution was obtained by adjusting the feed rate and atomization pressure. The atomization pressure was 0.2MPa. The yeast nutrient solution was added in two stages: the first addition was immediately upon yeast inoculation, and the second addition was made during the later stages of fermentation, when 36wt% of the grape juice sugar had been consumed.

[0055] D. Yeast inoculation method: Intermittent inoculation is adopted. First, 5g of non-brewing yeast is added to the grape juice, and after fermentation for 48 hours, 50g of brewing yeast is added and fermentation continues.

[0056] E. Fermentation conditions:

[0057] Fermentation temperature was controlled at 15℃;

[0058] Fermentation time is 7 days, until the specific gravity of the fermentation liquid is ≤1.000;

[0059] The pH of the fermentation broth is 3.0;

[0060] Step E above is carried out in a sealed fermentation tank with gentle stirring twice a day.

[0061] Example 2

[0062] A. Raw material preparation: Prepare 1000g of grape juice.

[0063] B. Screening and preparation of bacterial strains: Take 125g of brewer's yeast and 52.5g of non-brewing yeast, the non-brewing yeast being selected as *Saccharomyces cerevisiae*; the brewer's yeast is in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g, non-Saccharomyces cerevisiae in dry powder form, activity ≥10 8 CFU / g.

[0064] C. Auxiliary materials:

[0065] 60g of sulfur dioxide (calculated as SO2) is added after the grape juice in step A is put into the tank;

[0066] 27.5g of yeast nutrient solution was prepared as follows: 15g of L-cysteine ​​hydrochloride was dissolved in 100g of phosphate buffer, and the pH was adjusted to 7.75; 15g of limonene was added, and the mixture was stirred at 200 rpm for 3 hours at 42.5℃; subsequently, spray drying was performed with an inlet air temperature of 150℃ and an outlet air temperature of 75℃, achieved by adjusting the feed rate and atomization pressure of 0.4MPa. The solution was added in two stages: the first stage was added during yeast inoculation, and the second stage was added during the later stages of fermentation, when approximately 38wt% of the grape juice sugar had been consumed.

[0067] D. Yeast inoculation method: Simultaneous inoculation is adopted, with the mass ratio of non-brewing yeast to brewing yeast being 1:5, and both are inoculated into the grape juice for fermentation.

[0068] E. Fermentation conditions:

[0069] Fermentation temperature was controlled at 18℃;

[0070] Fermentation time is 18 days, until the specific gravity of the fermentation liquid is ≤1.000;

[0071] The pH of the fermentation broth is 3.4;

[0072] Step E above is carried out in a sealed fermentation tank with gentle stirring twice a day.

[0073] Example 3

[0074] A. Raw material preparation: Prepare 1000g of grape juice.

[0075] B. Screening and preparation of strains: Take 175g of *Saccharomyces cerevisiae* and 77.5g of non-*Saccharomyces cerevisiae*, the non-*Saccharomyces cerevisiae* being the heat-resistant strain; the *Saccharomyces cerevisiae* is in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g, non-Saccharomyces cerevisiae in dry powder form, activity ≥10 8 CFU / g.

[0076] C. Auxiliary materials:

[0077] 80g of sulfur dioxide (calculated as SO2) is added after the grape juice in step A is put into the tank;

[0078] 42.5g of yeast nutrient solution was prepared as follows: 20g of L-cysteine ​​hydrochloride was dissolved in 120g of phosphate buffer, and the pH was adjusted to 8.0. 20g of limonene was added to the solution, and the mixture was stirred at 240 rpm for 3.25 hours at 45℃ to generate a cysteine-limonene conjugate. The homogeneous solution was then spray-dried at an inlet air temperature of 153℃ and an outlet air temperature of 76℃. The yeast nutrient solution was obtained by adjusting the feed rate and the atomization pressure to 0.5MPa. The yeast nutrient solution was added in two stages: the first stage was added immediately upon yeast inoculation, and the second stage was added during the later stages of fermentation, when approximately 39wt% of the grape juice sugar had been consumed.

[0079] D. Yeast inoculation method: Intermittent inoculation is adopted. First, 77.5g of non-brewing yeast is added to the grape juice, and after fermentation for 60 hours, 175g of brewing yeast is added to continue fermentation.

[0080] E. Fermentation conditions:

[0081] Fermentation temperature was controlled at 22℃;

[0082] Fermentation time is 24 days, until the specific gravity of the fermentation liquid is ≤1.000;

[0083] The pH of the fermentation broth is 3.6;

[0084] Step E above is carried out in a sealed fermentation tank with gentle stirring twice a day.

[0085] Example 4

[0086] A. Raw material preparation: Prepare 1000g of grape juice.

[0087] B. Screening and preparation of strains: Take 200g of *Saccharomyces cerevisiae* and 100g of a non-*Saccharomyces cerevisiae* strain, the non-*Saccharomyces cerevisiae* being *Hansenula polymorpha*; the *Saccharomyces cerevisiae* strain is in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g, non-Saccharomyces cerevisiae in dry powder form, activity ≥10 8 CFU / g.

[0088] C. Auxiliary materials:

[0089] 100g of sulfur dioxide (calculated as SO2) is added after the grape juice in step A is put into the tank;

[0090] The yeast nutrient solution (50g) was prepared as follows: 22g of L-cysteine ​​hydrochloride was dissolved in 130g of phosphate buffer, and the pH was adjusted to 8.3; 22g of limonene was added, and the mixture was stirred at 270 rpm for 3.5 hours at 47℃; spray drying was then carried out with an inlet air temperature of 155℃ and an outlet air temperature of 78℃, adjusting the feed rate and atomization pressure to 0.6MPa. It was added in two stages: the first time during yeast inoculation, and the second time during the later stages of fermentation, when approximately 40wt% of the grape juice sugar had been consumed.

[0091] D. Yeast inoculation method: Inoculate simultaneously, with the mass ratio of non-brewing yeast to brewing yeast being 1:4, and inoculate together with the grape juice for fermentation.

[0092] E. Fermentation conditions:

[0093] Fermentation temperature is controlled at 25℃;

[0094] Fermentation time is 30 days, until the specific gravity of the fermentation liquid is ≤1.000;

[0095] The pH of the fermentation broth is 3.8;

[0096] Step E above is carried out in a sealed fermentation tank with gentle stirring twice a day.

[0097] Comparative Example 1

[0098] A. Raw material preparation: Prepare 1000g of grape juice.

[0099] B. Screening and preparation of strains: Take 50g of Saccharomyces cerevisiae and 5g of non-Saccharomyces cerevisiae, specifically Hansenula polymorpha; the Saccharomyces cerevisiae shall be in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g, non-Saccharomyces cerevisiae in dry powder form, activity ≥10 8 CFU / g.

[0100] C. Auxiliary materials:

[0101] 20g of sulfur dioxide (calculated as SO2) is added after the grape juice in step A is put into the tank;

[0102] The yeast nutrient solution (5g) was prepared as follows: 8g of limonene was added to 70g of phosphate buffer solution, the pH was adjusted to 7.2, and the mixture was stirred at 130 rpm for 2.5 hours at 38℃. After the reaction, the homogeneous solution was spray-dried at an inlet air temperature of 145℃ and an outlet air temperature of 72℃. The yeast nutrient solution was obtained by adjusting the feed rate and the atomization pressure of 0.2MPa. The yeast nutrient solution was added in two stages: the first stage was added immediately upon yeast inoculation, and the second stage was added during the later stages of fermentation, when approximately 36wt% of the grape juice sugar had been consumed.

[0103] D. Yeast inoculation method: Intermittent inoculation is adopted. First, 5g of non-brewing yeast is added to the grape juice, and after fermentation for 48 hours, 50g of brewing yeast is added to continue fermentation.

[0104] E. Fermentation conditions:

[0105] The temperature should be controlled at 15℃;

[0106] Fermentation time is 7 days, until the specific gravity of the fermentation liquid is ≤1.000;

[0107] The pH of the fermentation broth is 3.0;

[0108] Step E above is carried out in a sealed fermentation tank with gentle stirring twice a day.

[0109] Comparative Example 2

[0110] A. Raw material preparation: Prepare 1000g of grape juice.

[0111] B. Screening and preparation of strains: Take 50g of Saccharomyces cerevisiae and 5g of non-Saccharomyces cerevisiae, specifically Hansenula polymorpha; the Saccharomyces cerevisiae shall be in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g, non-Saccharomyces cerevisiae in dry powder form, activity ≥10 8 CFU / g.

[0112] C. Auxiliary materials:

[0113] 20g of sulfur dioxide (calculated as SO2) is added after the grape juice in step A is put into the tank;

[0114] The yeast nutrient solution (5g) was prepared as follows: 8g of L-cysteine ​​hydrochloride was added to 70g of phosphate buffer, the pH was adjusted to 7.2, and the mixture was stirred at 130 rpm for 2.5 hours at 38℃. After the reaction, the homogeneous solution was spray-dried at an inlet air temperature of 145℃ and an outlet air temperature of 72℃. The yeast nutrient solution was obtained by adjusting the feed rate and the atomization pressure of 0.2MPa. The yeast nutrient solution was added in two stages: the first stage was added immediately upon yeast inoculation, and the second stage was added during the later stages of fermentation, when approximately 36wt% of the grape juice sugar had been consumed.

[0115] D. Yeast inoculation method: Intermittent inoculation is adopted. First, 5g of non-brewing yeast is added to the grape juice, and after fermentation for 48 hours, 50g of brewing yeast is added to continue fermentation.

[0116] E. Fermentation conditions:

[0117] The temperature should be controlled at 15℃;

[0118] Fermentation time is 7 days, until the specific gravity of the fermentation liquid is ≤1.000;

[0119] The pH of the fermentation broth is 3.0;

[0120] Step E above is carried out in a sealed fermentation tank with gentle stirring twice a day.

[0121] The test method and results of this invention:

[0122] 1) Sample preparation:

[0123] The fermented wine sample was extracted using liquid-liquid extraction (with dichloromethane as solvent and 1-octanol as internal standard), concentrated, and then analyzed. The method was validated and showed good linearity and high repeatability.

[0124] Volatile aroma compounds were pre-concentrated using the HS-SPME method, followed by quantification using GC-MS.

[0125] 2) Quantitative analysis:

[0126] Total esters and phenethyl acetate were quantified by GC-MS and calibrated using standards; β-damascene terpenes were evaluated using OAV (aroma activity value); higher alcohols (isoamyl alcohol) and volatile acids (such as caprylic acid and acetic acid) were measured using methods recommended by the International Organisation of Vine and Wine (OIV).

[0127] 3) Sensory evaluation

[0128] This study employed 15 professional wine tasters for blind tasting. The scoring dimensions included aroma complexity, fruit and floral notes, smoothness on the palate, balance of structure, and finish. Scoring was conducted on a 0-100 point scale. Details are shown in Tables 1 and 2.

[0129] Table 1 Quantitative Test Results

[0130]

[0131] Table 2 Sensory evaluation results

[0132]

[0133] As can be seen from the test results of the above embodiments and comparative examples, the present invention can effectively increase the total ester content, making the aroma of wine more complex and layered, the taste smoother and more delicate, and the aftertaste longer.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing wine using compound yeast to enhance flavor, characterized in that: Based on parts by weight, the following steps are included: A. Raw material preparation: 1000 servings of grape juice; B. Screening and preparing bacterial strains: 50-200 parts of brewing yeast; 5-100 parts of non-brewing yeast; C. Auxiliary materials: Sulfur dioxide 20-100 parts, added after the grape juice in step A is put into the tank; Add 5-50 parts of yeast nutrient solution in two separate applications, with the amount added in each application being the same. D. Vaccination method: The bacterial strains were inoculated using either simultaneous or spaced-out inoculation methods. Simultaneous inoculation: Non-brewing yeast and brewing yeast are inoculated together into the grape juice at the same mass ratio for fermentation; Intermittent inoculation: First, non-brewing yeast is added to the grape juice, and then brewing yeast is added to continue fermentation; E. Fermentation conditions: Fermentation temperature: 15-25℃; Fermentation time: 7-30 days, until the specific gravity of the fermentation liquid is ≤1.000; Fermentation broth pH: 3.0-3.8; After fermentation, a wine with enhanced flavor from compound yeast is produced; The method for preparing the yeast nutrient includes, by mass fraction: H1. Reaction steps: Dissolve 8-22 parts of L-cysteine ​​salt in 70-130 parts of phosphate buffer, adjust the pH to 7.2-8.3 to obtain solution A; add 8-22 parts of limonene to solution A, and stir at 130-270 rpm for 2.5-3.5 hours at 38-47℃ to generate cysteine-limonene conjugate to obtain solution B; H2. Post-processing steps: The solution B obtained in step H1 is subjected to spray drying. The inlet air temperature of the spray drying process is 145-155℃, and the outlet air temperature is 72-78℃. Yeast nutrients are obtained by adjusting the feed rate and atomization pressure. The atomization pressure is 0.2-0.6MPa.

2. The method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: The brewing yeast is in dry powder form with an activity ≥20×10⁻⁶. 9 CFU / g.

3. The method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: The non-brewing yeast is in dry powder form with an activity ≥10. 8 CFU / g.

4. The method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: The non-brewing yeast is selected from one of Hansenula polymorpha, Magemont yeast, and thermostable Lachnos yeast.

5. The method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: The yeast nutrient is added in two stages: the first stage is added immediately upon yeast inoculation, and the second stage is added during the later stages of fermentation, when the grape juice sugar content has reached 36-40 wt%.

6. The method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: In step D, when simultaneous inoculation is used, the mass ratio of non-Saccharomyces cerevisiae to Saccharomyces cerevisiae is 1:10 to 1:

4.

7. The method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: In step D, when using intermittent inoculation, first inoculate 5-100 parts of non-brewing yeast, ferment for 48-72 hours, and then inoculate 50-200 parts of brewing yeast.

8. The method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: Step E is carried out in a sealed fermentation tank, with static or light stirring, 1-2 times daily.

9. A method for preparing wine using compound yeast to enhance flavor according to claim 1, characterized in that: In step E, after fermentation, the resulting wine is cold-stabilized for 3-7 days at 0-4℃.

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