Fermented sour cherry fruit wine and brewing method thereof

Abstract

The invention provides fermented sour cherry fruit wine and a brewing method thereof. According to the invention, the frozen European acid cherry fruits with poor fresh taste are used as raw materials, a novel fermentation type acid cherry fruit wine brewing process is developed, the acid cherry fruit wine with clear color, full wine body, rich aroma levels, prominent flavor typicality and stable quality is developed, the transformation of the acid cherries from non-fresh superior raw materials to high-added-value processed products is promoted, and the acid cherry fruit wine is suitable for large-scale production. The process framework can be further expanded to development of other high-acid characteristic fruit resources, and the method has important industrial value for promoting deep processing of characteristic agricultural products and enriching healthy drink categories.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to fermented sour cherry wine and a brewing method thereof. Background Art

[0002] Tart cherries (Prunus cerasus L.) are the fruit of a deciduous tree in the Rosaceae family, native to the Black Sea coast of Anatolia. Due to its early ripening period, it is known as the "first fruit of early spring." With its vibrant color and unique flavor, tart cherries are rich in polyphenols, protein, vitamins, calcium, iron, and other nutrients, making them a valuable source of phytochemicals. In recent years, tart cherries have been highly praised as a "superfruit," with numerous publications reporting their nutritional benefits, including modulating inflammatory factors, preventing cardiovascular and cerebrovascular diseases, improving sleep quality, and facilitating exercise recovery.

[0003] Sour cherries have high acidity and low sugar content, and their low sugar-to-acid ratio makes them unsuitable for fresh consumption. As a non-climacteric stone fruit, sour cherries can only be stored under refrigeration for a week. Their low osmotic resistance and high respiration rate lead to rapid softening and water loss after harvest, resulting in a rapid decline in quality and a short shelf life and storage period. Therefore, the greatest obstacles to the growth of global fresh sour cherry consumption are the fruit's poor taste, perishability, and limited storage technology. Given these characteristics, sour cherry processing has become an effective means of extending its industrial chain. Sour cherries are widely used in the food industry to produce common foods such as preserved fruit (frozen, dried, or canned), beverages (juices or alcoholic beverages), sweets (jams, candies, and jellies), and natural colorants. Summary of the Invention

[0004] The purpose of the present invention is to develop a fermented sour cherry wine with a typical sour cherry flavor using European sour cherry industrial frozen fruit as a main raw material, so as to overcome the application difficulties of sour cherry resources such as high acidity and short shelf life, improve utilization rate and reduce resource waste.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A method for brewing fermented sour cherry wine comprises the following steps:

[0007] 1) removing stems and pits from sour cherries, and crushing them at low temperature to obtain a mixture of sour cherry peels and sour cherry juice, i.e., cherry mash;

[0008] 2) Pour the obtained cherry mash into a fermentation tank, dilute with water, stir well, add pectinase, and perform enzymatic hydrolysis;

[0009] 3) Sulfur dioxide (SO2) treatment is performed after enzymatic hydrolysis;

[0010] 4) Activation of dry yeast powder: Add active dry yeast powder to the diluted sour cherry juice (crushed at low temperature) at a constant temperature and allow to stand to obtain a yeast activation solution;

[0011] 5) adjusting the cherry mash obtained in step 3) to the target sugar content, adding yeast activation solution, and initiating alcohol fermentation;

[0012] 6) Separation of skins and dregs: Stop maceration before the end of fermentation, perform preliminary coarse filtration on the fermentation liquid, collect the wine that flows directly out without pressing (free-flow wine) and the pressed wine obtained after pressing the skins and dregs, mix them, and let them settle naturally;

[0013] 7) Filtration and transfer: When the sugar content of the system no longer decreases, the fruit wine fermentation activity is completed, the upper layer of sake is separated, and the resulting sake is transferred to a new fermentation tank for full storage;

[0014] 8) Initiation of malic acid-lactic acid fermentation: Dissolve Viniflora CH11 Oenococcus oeni powder and inoculate it into sake to initiate malic acid-lactic acid fermentation;

[0015] 9) terminating the fermentation;

[0016] 10) Adjust the acidity to 5-6 g / L, bottle, and age.

[0017] The above method further comprises, before step 1), sterilizing the containers for alcohol fermentation and malic acid-lactic acid fermentation, all fermentation vessels and tools, wherein the sterilization may be specifically performed at 105° C. for 10 minutes;

[0018] In step 1), the sour cherry raw material is freshly picked European sour cherry fruits and / or European sour cherry industrial frozen fruits;

[0019] Do not crush the peel during the low-temperature crushing process;

[0020] In step 2), water is added to dilute the material liquid in a weight ratio of 3:1 to 4:1 (i.e., 1 part water is added to 4 parts cherry mash);

[0021] The volume of cherry mash (i.e. fermented juice) after dilution with water shall not exceed 80% of the tank capacity;

[0022] Based on the weight of the fermented juice, the amount of pectinase added was 0.1% (0.1 g pectinase for 100 g fermented juice). The pectinase was Lallzyme EX-V pectinase with an enzyme activity of ≥26000 PGLALu / g.

[0023] The enzymatic hydrolysis is as follows: enzymatic hydrolysis is carried out in a constant temperature water bath at 37°C for 2 to 3 hours to promote maceration and increase juice yield;

[0024] Excessively high enzymatic hydrolysis temperature may cause polyphenols to oxidize and brown, thus destroying the color quality of the juice;

[0025] The operation of step 3) of the above method is as follows: after the enzymatic hydrolysis is completed, food-grade potassium metabisulfite powder is added, the container is sealed, and the sour cherry mash is subjected to cold maceration treatment;

[0026] The amount of food-grade potassium metabisulfite powder added is 86.85-104.21 mg / L (86.85-104.21 mg / L of food-grade potassium metabisulfite powder added to 1L of sour cherry mash after enzymatic hydrolysis), which is equivalent to 50-60 mg / L of SO2 addition;

[0027] The cold soaking treatment is carried out at a temperature below 10°C;

[0028] The cold soaking treatment may last for 24 to 48 hours, specifically 28 hours.

[0029] In step 4) of the above method, the active dry yeast powder can specifically be Angel Wine Active Dry Yeast Powder CECA;

[0030] Add 10 times the yeast weight of sour cherry juice (3 times diluted with water) (meaning 1g of yeast is activated with 10g of 3-fold diluted low-temperature crushed sour cherry juice) to 37°C, add the yeast, and let it stand in a 37°C constant temperature incubator for 15-30 minutes to complete activation, thereby obtaining a yeast activation solution.

[0031] In step 5) of the above method, the cherry mash after cold soaking is adjusted to the target sugar content using white sugar or glucose.

[0032] The target sugar content is 21.3°Brix;

[0033] The yeast inoculum was 0.012% (based on 100 g of the cold-macerated cherry mash obtained in step 3, and 0.012 g of active dry yeast was added);

[0034] The temperature of the alcohol fermentation may be 20-30°C;

[0035] 3-4 hours after adding the yeast activation solution, obvious fermentation can be seen. The yeast ferments rapidly to produce bubbles, and the fermented liquid begins to separate into layers. The upper part forms a scum cap, and the color of the original juice in the lower part gradually deepens, and the flavor shows a winey taste.

[0036] During the alcoholic fermentation process, the fermentation liquid was placed at 20-30°C for fermentation, and the fermentation temperature and sugar content were monitored every 8 hours. At the same time, the pressed skin cap was immersed in sour cherry juice to promote maceration.

[0037] Alcoholic fermentation lasts 5 to 7 days;

[0038] In step 6) of the above method, maceration is stopped before the end of the fermentation activity, and the fermentation liquid is initially coarsely filtered using a 100-mesh sterile filter bag. The wine that flows out directly without being pressed is called free-flow wine, which generally accounts for more than 80% of the total amount. The pressed wine obtained after pressing the skins and residues generally accounts for 15%; the last pressed wine is controlled at about 2%.

[0039] In step 7) of the above method, the fermentation is nearing the end when: a small amount of bubbles occasionally appear on the liquid surface, mostly concentrated on the bottle wall; the fruit wine begins to separate, and the sludge is deposited at the bottom; the specific gravity of the wine drops to 0.992-0.996;

[0040] Use a 200-300 mesh strainer to separate the upper layer of sake;

[0041] In step 8) of the above method, Viniflora CH11 Oenococcus oeni powder is dissolved in water at a ratio of 1:1000, and inoculated into sake at a ratio of 4% (4g of Viniflora CH11 Oenococcus oeni powder aqueous solution is added to 100g of sake) to initiate malic acid-lactic acid fermentation;

[0042] During the malic acid-lactic acid fermentation, the temperature is controlled at 18-25°C, the container is kept sealed, and fermentation is carried out under anaerobic conditions for 10-15 days;

[0043] In step 9) of the above method, after the malic acid-lactic acid fermentation is completed, 86.85-104.21 mg / L potassium metabisulfite is added to terminate the fermentation;

[0044] In step 10) of the above method, the total acid content in the fruit wine is determined, and the amount of reagent is calculated according to the acid reduction amount of sodium carbonate - the amount added equation y = 1.2039x + 0.1323. According to the required acid reduction amount (y value), the corresponding food-grade sodium carbonate dosage (x value) is added to reduce the acidity of the final sour cherry wine to 5-6 g (total acid content) / L, thereby completing the acid reduction treatment;

[0045] The brewed sour cherry wine is bottled and aged in a low-temperature, dark environment for 2 to 4 months.

[0046] The sour cherry wine prepared by the above method also belongs to the protection scope of the present invention

[0047] The sour cherry wine has a bright color, a full body, rich aroma layers, a prominent typical flavor and stable quality.

[0048] The pH of sour cherry juice provides ideal growth conditions for brewer's yeast, resulting in stable yields and a distinct cherry aroma. This not only ensures the alcohol and acidity in wine, but also helps shape the unique flavor of sour cherries, making it a high-quality winemaking ingredient. Developing sour cherry resources into fermented sour cherry wine not only provides a new application path for sour cherry raw materials, overcoming the bottleneck of high acidity and short shelf life, and increasing its added value, but also provides a sour cherry wine brewing process for the fruit wine and beverage industry, providing a theoretical basis and technical reference for the development of high-acid fruit resources.

[0049] The beneficial effects of the present invention are as follows: the present invention utilizes European sour cherry jelly fruit raw materials with poor fresh taste to develop a new fermented sour cherry wine brewing process, and develops sour cherry wine with clear color, full body, rich aroma layers, outstanding typical flavor and stable quality. It not only promotes the transformation of sour cherry from a non-fresh food advantage raw material to a high-value-added processed product, but its process framework can also be expanded to the development of other high-acid specialty fruit resources, which has important industrial value for promoting the deep processing of specialty agricultural products and enriching the category of healthy drinks. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The figure shows the effect of different pectinase addition amounts on the juice yield of sour cherry jelly in Example 1 of the present invention.

[0051] Figure 2 The figure shows the effect of different pectinase addition amounts on the clarity of sour cherry jelly in Example 1 of the present invention.

[0052] Figure 3 The figure shows the effect of different initial sugar contents on the alcohol content of sour cherry wine in Example 2 of the present invention.

[0053] Figure 4 The following is the effect of different initial sugar contents on the sensory quality of sour cherry wine in Example 2 of the present invention.

[0054] Figure 5 The following is the effect of different material-liquid ratios on the residual sugar content and alcohol content of sour cherry wine in Example 3 of the present invention.

[0055] Figure 6 The following is the effect of different material-liquid ratios on the sensory quality of sour cherry wine in Example 3 of the present invention.

[0056] Figure 7 The figure shows the effect of different cold soaking times on the total phenol content of sour cherry wine in Example 4 of the present invention.

[0057] Figure 8 The following is the effect of different cold soaking times on the anthocyanin content of sour cherry wine in Example 4 of the present invention.

[0058] Figure 9The following is the effect of different cold soaking times on the sensory quality of sour cherry wine in Example 4 of the present invention.

[0059] Figure 10 The figure shows the effect of different yeast inoculum amounts on the alcohol content of sour cherry wine in Example 5 of the present invention.

[0060] Figure 11 The following is the effect of different yeast inoculum amounts on the sensory quality of sour cherry wine in Example 5 of the present invention.

[0061] Figure 12 The effects of different acid reduction methods on the acidity, phenolic retention and overall sensory evaluation of sour cherry wine in Example 6 of the present invention are shown.

[0062] Figure 13 The following is the effect of different acid reduction methods on the sensory quality of sour cherry wine in Example 6 of the present invention.

[0063] Figure 14 The figure shows the effects of different acid reduction methods on the volatile aroma substances of sour cherry wine in Example 6 of the present invention. DETAILED DESCRIPTION

[0064] The present invention will be further described in detail below in conjunction with specific embodiments. The examples provided are only for illustrating the present invention and are not intended to limit the scope of the present invention. The examples provided below can serve as a guide for further improvements by those skilled in the art and are not intended to limit the present invention in any way.

[0065] Unless otherwise specified, the experimental methods in the following examples are conventional methods and were performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials and reagents used in the following examples, unless otherwise specified, were all commercially available.

[0066] The present invention discloses a brewing method of fermented sour cherry wine, which comprises the following specific steps:

[0067] Container preparation → destemming and crushing → diluting with water → adding pectinase (enzymatic hydrolysis) → sulfur dioxide treatment → yeast activation → starting alcohol fermentation → fermentation monitoring → separating skins and residues → filtering and transferring to tanks → starting malic acid-lactic acid fermentation → terminating fermentation → adjusting acidity → bottling and storage.

[0068] Step 1: Container preparation: Use a 20L glass fermentation tank for alcohol fermentation and an 8L glass fermentation tank for malic acid-lactic acid fermentation. Store the finished fruit wine in 187mL brown wine bottles. Sterilize all fermentation vessels and tools at 105℃ for 10 minutes before use.

[0069] Step 2: Destemming and Crushing: After removing the stems and pits from the sour cherry jelly, quickly crush the cherries by hand at low temperatures, avoiding crushing the skins. The mixture of sour cherry skins and sour cherry juice is called cherry mash, which is then poured into the fermentation tank.

[0070] Step 3: dilute with water and stir evenly. The volume of the fermented juice should be controlled to be about half of the tank capacity (10L).

[0071] Step 4: Add pectinase, stir to dissolve, seal the container, and perform enzymolysis in a constant temperature water bath at 37°C for 3 hours.

[0072] Step 5, sulfur dioxide (SO2) treatment: Food-grade potassium metabisulfite is used to provide SO2. After the enzymatic hydrolysis is completed, 104.21 mg / L K2S2O5 powder (equivalent to 60 mg / L SO2 addition) is quickly added. After sealing, the sour cherry mash is placed in a 4°C refrigerator for cold maceration.

[0073] Step 6. Activate dry yeast powder: Weigh a certain amount of Angel wine active dry yeast powder CECA, adjust the temperature of 10 times the yeast weight of 3 times diluted sour cherry juice to 37°C, add the yeast, and let it stand in a 37°C constant temperature incubator for 15 minutes. After taking it out and stirring slightly, the yeast activation is completed.

[0074] Step 7: Start alcohol fermentation: Use white sugar to adjust the cherry mash to the target sugar content, add yeast activation liquid, and start alcohol fermentation.

[0075] Step 8, fermentation monitoring: ferment the fermentation liquid at room temperature of 20-30°C, monitor the fermentation temperature and sugar content every 8 hours, draw a fermentation curve, and at the same time press the skin cap and immerse it in sour cherry juice to promote maceration.

[0076] Step 9, separation of skin residue: stop maceration before the end of fermentation, use 100 mesh sterile filter bag to separate the fermentation liquid from the upper skin residue, and control the final pressing wine to about 2%.

[0077] Step 10, filtration and tank transfer: When the sugar content no longer decreases, the fruit wine fermentation activity is completed. At this time, use a 300-mesh filter to separate the upper layer of sake and transfer the sake to a clean, sterile 8L fermentation tank for full storage.

[0078] Step 11: Initiate malolactic fermentation: Weigh 0.1g of Viniflora CH11 Oenococcus oeni powder and dissolve it in water at a ratio of 1:1000. Inoculate the sake at a 4% concentration (4g of Viniflora CH11 Oenococcus oeni powder in water per 100g of sake) to initiate malolactic fermentation. Maintain the temperature at 24°C in a sealed container and ferment under anaerobic conditions for 15 days.

[0079] Step 12, termination of fermentation: After the malolactic fermentation is completed, 104.21 mg / L potassium metabisulfite is added to each tank to terminate the fermentation.

[0080] Step 13, acidity adjustment: Determine the total acid content in the wine, calculate the reagent dosage according to the sodium carbonate acid reduction amount-addition amount equation y = 1.2039x + 0.1323, add the corresponding food-grade sodium carbonate dosage (x value) according to the required acid reduction amount (y value), so that the acidity of the final sour cherry wine is reduced to 5.5 g / L, completing the acid reduction treatment.

[0081] Step 14, bottling and storage: The fruit wine is divided into 187 mL brown wine bottles, 2 g / L French medium-toasted oak chips are added into the bottles as an aging material, and the bottles are sealed with heat shrink caps and sealed with heat shrink caps. The bottles are placed in a low temperature (10-15°C) and light-proof environment, and the humidity is maintained at 60% to 70%.

[0082] Preferably, in step three, water is added to dilute the feed liquid at a weight ratio of 4:1.

[0083] Preferably, in step 4, the amount of pectinase added is 0.1%.

[0084] Preferably, in step five, the cold soaking time is 28 hours.

[0085] Preferably, in step seven, the initial target sugar content of the fermented juice is adjusted to 21.3° Brix.

[0086] Preferably, in step seven, the yeast inoculation amount is 0.012%.

[0087] The technical solution of the present invention will be further described below in conjunction with specific experiments.

[0088] In order to further verify that the fermented sour cherry wine prepared by the present invention has excellent technical effects, the inventors also conducted the following measurement experiments.

[0089] Sensory evaluation: Evaluators with good tasting stability and consistency were selected to form a reliable and stable tasting panel. A scoring method (10-point system) was used to score the five items of fruit wine appearance, aroma, taste, typicality and overall evaluation according to the scoring criteria in Table 1, and the average of the scoring results was taken.

[0090] Table 1 Sensory evaluation table

[0091]

[0092]

[0093] The pectinase used in the following examples: Product model LALLZYME EX-V TM, purchased from Lallemand Inc., USA;

[0094] Wine active dry yeast powder CECA was purchased from Angel Yeast Co., Ltd.;

[0095] Oenococcus oeni: Product model Viniflora CH11 was purchased from Novonesis, Denmark.

[0096] Example 1: Effect of different pectinase addition amounts on the quality of sour cherry jelly juice

[0097] This example explores the effects of different pectinase addition amounts (0%, 0.05%, 0.10%, 0.15%, 0.20%) on the juice yield, transmittance, and turbidity of sour cherry mash. For specific measurement experiments and result data, see Figure 1 、 Figure 2 .

[0098] Figure 1 The results showed that the juice yield of the fruit before enzymatic hydrolysis was only 56.63±0.98%, but it increased significantly after enzymatic hydrolysis. When the enzyme addition was 0.10%, the juice yield of sour cherry fruit reached a peak (70.08±0.54%). There was no significant difference in the juice yield when the enzyme addition was 0.05%, 0.15% and 0.20%. The reason for this may be that after pectinase decomposes macromolecules such as pectin, the composition and pH of the fruit wine change significantly, which affects the activity of pectinase and reduces the juice yield. Figure 2 The changes in transmittance and turbidity showed that when the enzyme addition amount was greater than 0.10%, the transmittance and turbidity of the sour cherry juice were not significantly different from those of the blank group. However, when the enzyme addition amount was 0.05%, the transmittance of the juice was 80.65±0.66% and the turbidity reached 19.35±0.66%. In comparison, the transmittance was the worst and the turbidity was the highest.

[0099] According to the above results, when the pectinase addition amount was 0.10%, the juice yield of sour cherry fruit was the highest, and enzymatic hydrolysis had no obvious effect on the clarity and color quality of the juice. Therefore, this condition was used for enzymatic hydrolysis in subsequent experiments.

[0100] Example 2: Effect of different initial sugar contents on the quality of sour cherry wine

[0101] This example explores the effects of different initial sugar contents (17.8°Brix, 18.8°Brix, 19.8°Brix, 20.8°Brix, and 21.8°Brix) on the alcohol content and sensory scores of the final wine after the completion of alcoholic fermentation. For specific measurement experiments and result data, see Figure 3 、 Figure 4 .

[0102] observe Figure 3The alcohol content change curve shows that when the initial sugar content is ≤19.8, the alcohol content generated by fermentation does not change significantly. When the sugar content is ≥19.8, the alcohol content shows a clear upward trend. When the initial sugar content is 21.8°Brix, the alcohol content reaches the highest point of 10.26±0.29°Brix. Figure 4 Sensory evaluation results showed that as the initial sugar content increased, the alcohol content and fermentation broth sugar content gradually accumulated, the fruit wine aroma became richer, the flavor richness improved, and the taste and overall evaluation scores gradually increased. The optimal initial sugar content treatment in the single-factor experiment was determined to be 21.8°Brix. Therefore, orthogonal experiment recipe optimization was carried out with initial sugar content values of 21.3°Brix, 21.8°Brix, and 22.3°Brix.

[0103] Example 3: Effect of different material-liquid ratios (referring to the weight ratio of water added to dilute the material-liquid in step 2) on the quality of sour cherry wine

[0104] This example explores the effects of different material-liquid ratios (160g:0g, 140g:20g, 120g:40g, 100g:60g, 80g:80g) on the residual sugar content, alcohol content, and sensory score of fruit wine after fermentation (alcohol fermentation with active dry yeast). For specific measurement experiments and result data, see Figure 5 、 Figure 6 .

[0105] Depend on Figure 5 From the third day of fermentation, as the amount of water added increased, the residual sugar content gradually decreased from 3.95±0.19g / L to 2.24±0.03g / L. The change in alcohol content showed an opposite trend to the sugar content: with increasing dilution, the alcohol content at the end of fermentation gradually increased. This result suggests that diluted fermentation increases sugar consumption and leads to more thorough fermentation. Figure 6 The sensory evaluation results showed that the appearance characteristics of the fruit wine scored the highest at a material-liquid ratio of 120g:40g, while the original fruit fermentation group scored the lowest; the taste scores of the original fruit fermentation group and the 120g:40g treatment group were the highest, and as the dilution ratio increased, the taste score gradually decreased, becoming bland and thin; as the dilution amount increased, the aroma score decreased, and the aroma intensity gradually weakened; the flavor typicality of the undiluted group was prominent, and as the dilution ratio increased, the typicality score decreased, and the sour cherry flavor characteristics gradually weakened; the fruit wine obtained the lowest overall score (6.5±0.17) in the 80g:80g material-liquid ratio group, and there was no significant difference in the total scores of the other groups.

[0106] Based on the above results, the optimal material-liquid ratio was initially determined to be 120g:40g (i.e., a weight ratio of 3:1). This significantly improved the fermentation rate and infusion effect while minimizing flavor loss. Therefore, orthogonal experiment formulation optimization was conducted with material-liquid weight ratios of 2:1, 3:1, and 4:1.

[0107] Example 4: Effect of Different Cold Soaking Times (Referring to the Cold Soaking Time in the Sulfur Dioxide Treatment) on the Quality of Sour Cherry Wine

[0108] This example investigates the effects of different cold soaking times (0d, 1d, 2d, 3d) on the total phenol content, total anthocyanin content, and sensory scores of the final wine after fermentation (alcoholic fermentation with active dry yeast). For specific measurement experiments and result data, see Figure 7 、 Figure 8 and Figure 9 .

[0109] Depend on Figure 7 、 Figure 8 After the end of alcoholic fermentation, the total phenolic and anthocyanin contents of the wines were significantly increased after maceration with the skins, demonstrating that maceration effectively increases the extraction rate of phenolic compounds from the skins, improves sensory quality, and enhances the fullness of the wine. The order of total phenol extraction efficiency is 1 day > 0 day > 2 days > 3 days. When the cold maceration duration is 1 day, the total phenol extraction of the wine is the highest, reaching 1.34±0.02 g / L. As the cold maceration duration exceeds 1 day, the maceration efficiency gradually decreases. The anthocyanin content of the wines is highest when the cold maceration duration is 1 day and 2 days, followed by 1 day, and 3 days is the worst. These results indicate that the highest phenolic extraction is achieved when the cold maceration duration is 1 to 2 days, while the extraction efficiency of both total phenols and anthocyanins decreases when the maceration time is extended to 3 days. Excessive maceration time is detrimental to the stability of the phenolic compounds in sour cherry wines. Figure 9 The sensory index scores of the fruit wines from each fermentation group are shown in Figure 2. The appearance score was ranked as 0 days > 2 days > 1 day > 3 days. Based on aroma, flavor, typicality, and overall scores, the 2-day cold soaking treatment showed the best sensory quality, followed by the 1-day treatment, and the 3-day cold soaking treatment had the worst sensory quality.

[0110] According to the above test results, the optimal cold soaking time for the single factor experiment was determined to be 1d and 2d. Therefore, the cold soaking time of 28h, 36h, and 44h was selected for orthogonal experiment formula optimization.

[0111] Example 5: Effect of different yeast inoculation amounts on the quality of sour cherry wine

[0112] This example investigates the effects of different yeast inoculation amounts (0.005%, 0.01%, 0.02%, 0.03%, and 0.04%) on the alcohol content and sensory scores of the final wine after fermentation (alcohol fermentation with active dry yeast). For specific measurement experiments and result data, see Figure 10 、 Figure 11 .

[0113] Depend on Figure 10As can be seen, there was no significant difference in the alcohol content produced by fermentation when the yeast addition amount was 0.005%, 0.01%, and 0.02%, reaching a peak of 5.99±0.00%vol at 0.01%. When the inoculum amount exceeded 0.02%, the alcohol content showed a certain downward trend. Excessive yeast growth and reproduction consumed a large amount of nutrients in the raw materials, resulting in insufficient raw materials for alcohol fermentation, thereby reducing the amount of alcohol produced. Figure 11 Sensory evaluation results showed that the 0.005% yeast inoculum exhibited slightly inferior sensory quality compared to the other groups, with an overall score of only 4.35±0.47. Therefore, the optimal yeast inoculum levels in the single-factor experiment were 0.01% and 0.02%, and orthogonal experiments were conducted to optimize the formulation using yeast additions at 0.012%, 0.015%, and 0.018%.

[0114] Example 6: Orthogonal experiment to optimize fruit wine fermentation conditions

[0115] Based on the preliminary screening results of the single factor test, this example used the solid-liquid ratio, initial sugar content, cold soaking time, and yeast inoculation amount as factors to conduct a four-factor three-level L9 (3 4 An orthogonal experiment was conducted. After fermentation (alcoholic fermentation with active dry yeast), wine samples were centrifuged and filtered. Residual sugar content, alcohol content, total phenolic content, and total flavonoid content were measured, and sensory scores were performed. The data for each indicator were standardized using the normalization method. The weight coefficients of the five indicators were determined using the Analytic Hierarchy Process (AHP) method. A weighted comprehensive score was calculated, and the optimal fermentation process was determined based on the final score. The orthogonal experiment factor levels are shown in Table 2, and the comprehensive score calculation results are shown in Table 3.

[0116] Table 2 Orthogonal test factors and levels Table L9(3 4 )

[0117]

[0118] Table 3 Comprehensive evaluation of orthogonal experimental design results

[0119]

[0120] The R value can be used to determine the influence of various factors on the overall wine score. According to the results in the table, the order of factors influencing overall quality is: B (material-liquid ratio) > C (cold maceration time) > A (initial sugar content) > D (yeast inoculum size). Comparison of K values reveals the optimal combination to be A1B3C1D1, i.e., an initial sugar content of 21.3°Brix, a dilution material-liquid weight ratio of 4:1, a cold maceration time of 28 hours, and a yeast inoculum size of 0.012%. Under these optimal process conditions, the physical and chemical properties of the sour cherry wine after alcoholic fermentation were as follows: residual sugar content of 7.87±0.20 g / L, meeting the characteristics of an off-dry wine; alcohol content of 9.48±0.80%vol; total phenolic content of 1.52±0.13 g / L; total flavonoid content of 2.28±0.23 g / L; and a sensory score of 8.60±0.49. The finished product was a bright ruby red with a full body and clear color.

[0121] Example 7: Effects of different acid reduction methods on the quality of sour cherry wine

[0122] The present invention uses a chemical acid reduction method (sodium carbonate, adding 3.98g / L sodium carbonate to 30mL of sour cherry wine after alcohol fermentation to reduce the acidity of the wine to about 6.5g / L, and centrifuging), a physical acid reduction method (IRA67 resin, accurately weighing 1.0g of the pretreated resin, transferring it to a 100mL conical flask, adding 30mL of sour cherry wine after alcohol fermentation, stirring at a low speed of 120r / min on a magnetic stirrer for 24 hours, and then centrifuging), and a biological acid reduction method (malic acid-alcohol fermentation, weighing 10g of Lalvin 71B acid-reducing yeast powder, dissolving it in water at a ratio of 1:10, and then activating it in a constant temperature incubator at 37°C for 30 minutes, and inoculating the activated solution into 150mL of sour cherry wine sample at a ratio of 4% to start malic acid-alcohol fermentation; for malic acid-lactic acid fermentation, weighing 0.1g of Viniflora CH11 Oenococcus oeni powder was dissolved in water at a ratio of 1:1000. The powder solution was inoculated into 150 mL of sour cherry wine sample at a ratio of 4% to initiate malic acid-lactic acid fermentation. The wine was fermented for 15 days in each group. The wine was then subjected to acid reduction treatment. The total acid reduction, pH, total phenolic and total flavonoid retention rates of the wine were measured. Sensory evaluation was performed, and the acid reduction performance and quality impact of the three processes were compared. The changes in volatile organic compounds in the wine after acid reduction were analyzed using a GC-IMS flavor analyzer. Finally, the most suitable acid reduction method for sour cherry wine was determined. The specific determination experiments and results are shown in the table. Figure 12 、 Figure 13 and Figure 14 .

[0123] Effects of different acid reduction methods on pH, acid reduction amount, total phenol retention rate and total flavonoid retention rate of sour cherry wine Figure 12As for the acid-reducing effect, sodium carbonate treatment caused the greatest reduction in acidity, reaching 5.51±0.02 g / L. There was no significant difference in the acid-reducing amount between IRA67 resin treatment (4.93±0.20 g / L) and CH11 Oenococcus oeni inoculation (4.90±0.02 g / L). Comparison of the retention rates of total phenols and total flavonoids showed that IRA67 resin treatment seriously reduced the total phenols and total flavonoids contents in fruit wine, with the remaining amounts being 56.05±0.52% and 49.43±0.97%, respectively. After fermentation by 71B yeast and CH11 Oenococcus oeni, the total phenol retention rates in fruit wine were 84.31±0.00% and 88.87±0.58%, respectively, and the total flavonoid retention rates were 85.95±0.60% and 99.48±3.28%, respectively, indicating that biological acidification had a slight effect on their contents, and the retention rate of phenolic substances by CH11 Oenococcus oeni was higher than that of yeast. After sodium carbonate treatment, the retention rates of total phenols and total flavonoids were 101.03±0.39% and 103.91±2.14%, respectively, indicating that sodium carbonate treatment had no significant effect on the phenolic content of fruit wine.

[0124] The sensory quality of sour cherry wine treated with different acid reduction methods was evaluated. Figure 13 As shown in the sensory score radar chart, the chemical (sodium carbonate) treatment resulted in the highest overall sensory score and the best flavor. The CH11 Oenococcus oeni acid reduction group had a sensory score similar to the sodium carbonate treatment group, while also imparting frankincense and a distinct secondary aroma (fermentation aroma) to the wine, resulting in a richer aroma layer and the highest aroma score. The resin (IRA67) acid reduction treatment resulted in a significantly lighter color and an unpleasant resinous flavor, resulting in the worst sensory quality.

[0125] In order to confirm the differences among chemical, physical and biological methods of acid reduction on the aroma quality of sour cherry wine, GC-IMS flavor analyzer was used to detect the aroma components of each group of wine samples and draw a two-dimensional fingerprint. Figure 14As shown. In the figure, the label 0 represents the blank group wine sample without acid reduction, the label Na represents the wine sample in the Na2CO3 acid reduction treatment group, and the label Na+CH11 means that the wine sample was first inoculated with CH11 Oenococcus oeni, and then Na2CO3 was added to adjust the acidity to a palatable level. Each horizontal row represents the different volatile substances contained in the wine sample, and each vertical column represents the difference in the content of the corresponding compound in different wine samples. The flavor analysis results detected a total of 75 volatile organic compounds, including 17 alcohols, 9 ketones, 15 esters, 6 aldehydes, 3 hydrocarbons, 5 terpenes, 2 organic acids, 11 heterocyclic compounds, 6 sulfur-containing compounds and 1 nitrogen-containing compound. In summary, sodium carbonate acid reduction treatment had no significant effect on the aroma of sour cherry wine; IRA67 resin had a good adsorption effect on sharp irritating gases such as 3-methyl-2-butanol, ethyl valerate, decahydronaphthalene, geosmin, pyridine and dipropyl disulfide, but also released unpleasant pungent flavors such as (E,E)-2,4-hexadienal, 2-methylpropionic acid and diethyl disulfide; although the metabolic activity of 71B yeast could reduce the content of 3-methyl-2-butanol, geosmin and dipropyl disulfide to a certain extent, it produced a large amount of 2-methylisoborneol and ethyl valerate, which made the wine have a prominent earthy, musty and pungent fatty taste; in contrast, the malolactic fermentation activity of CH11 Oenococcus oeni not only reduced the content of sour cherry wine, but also The volatile compounds with undesirable flavors, such as spicy and irritating taste (3-methyl-2-butanol, (E,E)-2,4-hexadienal, 2-methylpropionic acid, pyridine, dipropyl disulfide, etc.), earthy smell (geosmin), spice and mint flavor (sotolon, isophorone, decahydronaphthalene), etc., were increased, while the mature fruity aroma of fruit wine, such as soft fruity aroma (1-hexanol, 2-heptanone, propyl succinate), rose and honey sweet aroma (butyl phenylacetate), black pepper (2-methylhexyl butyrate), fresh fragrance (butyraldehyde), floral fragrance (allyl acetic acid), and nutty and cocoa-like aroma (2-ethylpyrazine), was enhanced, forming a complex second-class aroma (fermentation aroma of fruit wine); while the aroma of fruit wine in the CH11 Oenococcus oenii + sodium carbonate group after treatment had no significant difference from that in the Oenococcus oenii fermentation group.

[0126] The quality changes of sour cherry wine in the above acid reduction experiments are summarized as follows: sodium carbonate has a high acid reduction rate, minimal impact on wine quality, and good sensory evaluation, but it fails to improve the wine's aroma, and the high addition level imparts an unpleasant saltiness. Although CH11 Oenococcus oeni can enrich the wine's aroma, its acid reduction ability is lower than that of sodium carbonate. IRA67 resin performs poorly in all performance indicators, with poor sensory quality, weak acid reduction effect, and low phenolic retention, making it unsuitable for actual winemaking. Ultimately, a combined acid reduction process using sodium carbonate and CH11 Oenococcus oeni was selected as the most suitable acid reduction process for sour cherry wine. After the alcoholic fermentation, the sour cherry wine was inoculated with CH11 Oenococcus oeni for approximately 10 days of malic acid-lactic acid fermentation. After fermentation, sodium carbonate was added to adjust the total acid content to 5.5 g / L.

[0127] Example 8: Brewing of fermented sour cherry wine

[0128] In a 20L glass fermenter, 8kg of European sour cherry jelly was destemmed and crushed, then poured into the fermenter. 2kg of drinking water was added. 10g of pectinase (Lallzyme EX-V pectinase, activity ≥26,000 PGLALu / g) was added, stirred to dissolve, and then sealed. Enzymatic hydrolysis was performed in a 37°C waterbath for 3 hours. 1.042g of food-grade potassium metabisulfite was quickly added after hydrolysis. The sour cherry mash was sealed and placed in a 4°C refrigerator for cold maceration for 28 hours. 1.2g of Angel Wine Active Dry Yeast (CECA) was weighed, and 12g of sour cherry juice (diluted 3x with water) was tempered to 37°C. The yeast was then added and activated in a 37°C incubator for 15 minutes. The cherry mash was adjusted to 21.3° Brix with white sugar, and yeast activation solution was added to initiate alcoholic fermentation. The room temperature was maintained at 24°C for 7 days. The day before fermentation ended, maceration was stopped and the fermentation liquid was squeezed and separated from the upper layer of pomace using a 100-mesh sterile filter bag. When the sugar content no longer decreased, the wine fermentation was completed. The upper layer of clear wine was separated using a 300-mesh filter and transferred to a clean, sterile 6-L fermenter for full storage. 0.24g of Viniflora CH11 Oenococcus oeni powder was weighed and dissolved in water at a ratio of 1:1000. The culture solution was inoculated into the sour cherry wine at a 4% ratio (240mL of the culture solution was inoculated into the sour cherry wine) to initiate malolactic fermentation. The temperature was controlled at 24°C during fermentation, and the container was kept sealed. Fermentation was carried out under anaerobic conditions for 15 days. After the malolactic fermentation was completed, 625.26mg of potassium metabisulfite powder was added to terminate the fermentation. The total acid content of the wine was determined to be 6.5 g / L. 4.32 g of food-grade sodium carbonate powder was added to reduce the acidity of the final sour cherry wine to 5.51 ± 0.02 g / L, completing the acid reduction treatment. The 6 L of acid-reduced wine was divided into empty brown bottles, each containing 187 mL. The bottles were sealed with heat shrink caps and stored in a dark environment at a low temperature (10°C to 15°C) with a humidity of 60% to 70%.

[0129] Under the optimal process conditions, the physical and chemical indicators of sour cherry wine were measured as follows: reducing sugar content was 7.87±0.20 g / L, alcohol content was 9.48±0.80% vol, total phenol content was 1.52±0.13 g / L, total flavonoids content was 2.28±0.23 g / L, and sensory score was 8.60±0.49.

[0130] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that further improvements can be made to the present invention. In short, according to the principles of the present invention, this application is intended to include any changes, uses or improvements to the present invention, including changes that depart from the disclosed scope in this application and are made using conventional techniques known in the art.

Claims

1. A method for brewing fermented sour cherry wine, comprising the following steps: 1) removing stems and pits from sour cherries, and crushing them at low temperature to obtain a mixture of sour cherry peels and sour cherry juice, i.e., cherry mash; 2) Pour the obtained cherry mash into a fermentation tank, dilute with water, stir well, add pectinase, and perform enzymatic hydrolysis; 3) sulfur dioxide treatment after enzymatic hydrolysis; 4) Activation of dry yeast powder: Add active dry yeast powder to the diluted sour cherry juice (crushed at low temperature) at a constant temperature and allow to stand to obtain a yeast activation solution; 5) adjusting the cherry mash obtained in step 3) to the target sugar content, adding yeast activation solution, and initiating alcohol fermentation; 6) Separation of skins and dregs: Stop maceration before the end of fermentation, perform preliminary coarse filtration on the fermentation liquid, collect the wine that flows directly out without pressing and the pressed wine obtained after pressing the skins and dregs, mix them, and let them settle naturally; 7) Filtration and transfer: When the sugar content of the system no longer decreases, the fruit wine fermentation activity is completed, the upper layer of sake is separated, and the resulting sake is transferred to a new fermentation tank for full storage; 8) Initiation of malic acid-lactic acid fermentation: Dissolve Viniflora CH11 Oenococcus oeni powder and inoculate it into sake to initiate malic acid-lactic acid fermentation; 9) terminating the fermentation; 10) Adjust the acidity to 5-6 g / L, bottle, and age.

2. The method according to claim 1, characterized in that In step 1), the sour cherry raw material is freshly picked European sour cherry fruits and / or European sour cherry industrial frozen fruits.

3. The method according to claim 1, characterized in that In step 2), water is added to dilute the feed liquid to a weight ratio of 3:1 to 4:1; Based on the weight of the fermented juice, the added amount of pectinase is 0.1%, and the pectinase is Lallzyme EX-V pectinase with an enzyme activity of ≥26000PGLALu / g; The enzymatic hydrolysis is carried out in a constant temperature water bath at 37° C. for 2 to 3 hours.

4. The method according to claim 1, wherein The operation of step 3) is as follows: after the enzymatic hydrolysis is completed, food-grade potassium metabisulfite powder is added, the container is sealed, and the sour cherry mash is cold-macerated; The amount of food-grade potassium metabisulfite powder added is 86.85-104.21 mg / L, which is equivalent to 50-60 mg / L SO2 addition; The cold soaking treatment is carried out at a temperature below 10°C; The cold soaking treatment lasts for 24 to 48 hours.

5. The method according to claim 1, wherein In step 4), tart cherry juice (3-fold dilution) with a volume of 10 times the weight of the yeast is adjusted to 37° C., and then the yeast is added. The mixture is allowed to stand in a 37° C. constant temperature incubator for 15 to 30 minutes to complete activation, thereby obtaining a yeast activation solution.

6. The method according to claim 1, characterized in that In step 5), the cherry mash after cold soaking is adjusted to the target sugar content using white sugar or glucose. The target sugar content is 21.3°Brix.

7. The method according to claim 1, characterized in that In step 5), the yeast inoculation amount is 0.012%; The temperature of the alcohol fermentation is 20-30°C; Alcoholic fermentation lasts for 5 to 7 days.

8. The method according to claim 1, characterized in that In step 6), the immersion is stopped before the fermentation activity is completed, and the fermentation liquid is subjected to preliminary coarse filtration using a 100-mesh sterile filter bag; In step 7), the upper layer of sake is separated using a 200-300 mesh filter.

9. The method according to claim 1, characterized in that In step 8), Viniflora CH11 oeni powder is dissolved in water at a ratio of 1:1000 and inoculated into sake at a ratio of 4% to initiate malic acid-lactic acid fermentation; During the malic acid-lactic acid fermentation, the temperature is controlled at 18-25°C, the container is kept sealed, and fermentation is carried out under anaerobic conditions for 10-15 days; In step 9), after the malic acid-lactic acid fermentation is completed, 86.85-104.21 mg / L potassium metabisulfite is added to terminate the fermentation; In step 10), the total acid content in the wine is determined, and the amount of reagent is calculated according to the acid reduction amount of sodium carbonate-addition amount equation y=1.2039x+0.1323. The corresponding food-grade sodium carbonate dosage (x value) is added according to the required acid reduction amount (y value) to reduce the acidity of the final sour cherry wine to 5-6 g (total acid content) / L, thereby completing the acid reduction treatment; The brewed sour cherry wine is bottled and aged in a low-temperature, dark environment for 2 to 4 months.

10. Sour cherry wine brewed by the method according to any one of claims 1 to 9.

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