Red jujube and sand jujube fruit wine and preparation method thereof

Abstract

This invention relates to the field of fruit wine brewing technology, and discloses a jujube and jujube fruit wine and its brewing method. The brewing method for jujube and jujube fruit wine includes the following steps: Step S1: Select jujubes and jujubes, wash them, remove the pits, cut them into pieces, add water, boil, filter through gauze, and cool to obtain a liquid for later use; Step S2: Add pectinase to the liquid for enzymatic hydrolysis, then add DL-malic acid to adjust the pH, add white sugar to adjust the sugar content of the juice, and add sulfur dioxide for sterilization and antioxidation; Step S3: Inoculate with activated brewing yeast and *C. sacchariformis* to ferment and obtain a fermentation liquid; Step S4: Centrifuge the fermentation liquid to obtain the fruit wine. This invention uses a compound formula of jujubes and jujubes as raw materials, and uses brewing yeast and *C. sacchariformis* for fermentation, achieving complementarity of nutrients and metabolic substrates, improving raw material utilization, resulting in a more harmonious flavor profile and improved overall quality.

Description

Technical Field

[0001] This invention relates to the field of fruit wine brewing technology, and discloses a jujube and jujube fruit wine and its brewing method. Background Technology

[0002] Red dates, the mature fruit of plants in the genus Ziziphus of the family Rhamnaceae, are a highly representative food and medicinal resource. Rich in vitamins, minerals, dietary fiber, polyphenols, flavonoids, polysaccharides, and other nutrients and functional active ingredients, red dates possess extremely high nutritional value and potential for deep processing. However, fresh red dates have poor storage resistance after harvesting, and are prone to quality deterioration during transportation and storage, such as softening of the flesh, browning of the fruit, and nutrient loss, significantly reducing their commercial value and hindering the industrial promotion of fresh red dates.

[0003] Large-fruited Elaeagnus angustifolia is a superior cultivated variety belonging to the Elaeagnaceae family and the Elaeagnus genus, possessing significant ecological and economic value. The fruit is rich in nutrients such as sugars, proteins, amino acids, lipids, minerals, and vitamins, offering a comprehensive nutritional profile. However, due to limitations in fruit texture and flavor, the direct consumption experience of large-fruited Elaeagnus angustifolia is poor, resulting in low market acceptance and a narrow market for fresh consumption. Currently, research on deep processing technologies and the development of high-value-added products for large-fruited Elaeagnus angustifolia are still lacking, leading to a significant waste of resources. Therefore, developing high-value processing technologies and products for large-fruited Elaeagnus angustifolia is of great practical significance for revitalizing Elaeagnus angustifolia resources, achieving efficient industrial utilization, and improving the economic benefits of Elaeagnus angustifolia cultivation.

[0004] Fermented fruit wine is a low-alcohol beverage made primarily from fresh fruit or fruit juice (pulp) through microbial alcoholic fermentation. It retains the original nutrients and flavor of the fruit, and moderate consumption is beneficial to health. Compared to single-fruit wines, compound-fermented fruit wines combine the nutritional advantages and flavor characteristics of multiple fruits, overcoming the shortcomings of single-origin wines in terms of flavor and nutritional content. This results in superior taste and quality, and a promising market outlook. Malolactic fermentation (MLF) is an indispensable biological deacidification and flavor improvement process in fruit wine production. This process, through the metabolic action of lactic acid bacteria, converts the highly irritating L-malic acid in fruit wine into the milder L-lactic acid, effectively optimizing the organic acid composition of the wine, reducing its astringency, enriching flavor compounds, and enhancing the overall quality of the wine. It is a core technology for improving the sensory quality and storage stability of fruit wine.

[0005] Currently, there are a few reports on research into single-fruit wines made from jujube and jujube, but research on the co-fermentation of these two fruits as main ingredients to prepare compound fruit wines remains lacking. The combined resource advantages of these two distinctive fruits have not yet been explored and utilized. Therefore, it is necessary to provide a jujube and jujube fruit wine and its brewing method to solve the aforementioned technical problems. Summary of the Invention

[0006] The main objective of this invention is to provide a jujube and jujube fruit wine and its brewing method, aiming to solve the problems of limited development of jujube and jujube products and low resource utilization.

[0007] To achieve the above objectives, the present invention provides a method for brewing jujube and red date wine, comprising the following steps: Step S1: Select red dates and sand dates, wash them, remove the pits, cut them into pieces and prepare the ingredients. Add water and boil them, then filter them through gauze and cool them to obtain the liquid. The mass ratio of red dates to sand dates is 1:0.5-2. The ratio of raw materials to hot water in the liquid is 1:3-1:7. Step S2: Add pectinase to the liquid for enzymatic hydrolysis, then add DL-malic acid to adjust the pH, add white sugar to adjust the sugar content of the juice, and add sulfur dioxide for sterilization and anti-oxidation. Step S3: Inoculate the activated brewing yeast and *Coccus faecium* into the liquid treated in step S2 to obtain a fermentation broth. The amount of brewing yeast inoculated is 0.3-0.7% of the fermentation broth volume, and the amount of *Coccus faecium* inoculated is 1.0-2.2% of the fermentation broth volume. Step S4: Centrifuge the fermentation liquid to obtain fruit wine.

[0008] Optionally, the fermentation in step S3 is specifically carried out at a temperature of 20-30℃ for 6-8 days.

[0009] Optionally, the brewing yeast in step S3 is specifically Angel Fruit Wine Yeast, and the inoculation amount of Angel Fruit Wine Yeast is 0.5%.

[0010] Optionally, the amount of *Chlorella vulgaris* inoculated in step S3 is 1.6%.

[0011] Optionally, in step S1, the mass ratio of red dates and sand dates is 1:1; and the material-to-liquid ratio of raw materials to water is 1:5.

[0012] Optionally, the boiling time in step S1 is 40-50 minutes, and the cooling temperature is 36-40°C.

[0013] Optionally, in step S2, the amount of pectinase added is 0.3 g / L, the enzymatic hydrolysis temperature is 45°C, and the enzymatic hydrolysis time is 4 h.

[0014] Optionally, in step S2, the pH is adjusted to 3.6-4.4; the sugar content of the fruit juice is adjusted to 15-21°Bx; and the amount of sulfur dioxide added is 40 mg / L based on the volume of the liquid.

[0015] Optionally, the centrifugation process in step S4 specifically involves centrifuging the fermentation broth for 10 minutes at 4°C and 8000 r / min.

[0016] The present invention also provides a jujube and jujube fruit wine prepared using the above-described brewing method.

[0017] The application of the technical solution of the present invention has at least the following beneficial effects: (1) This invention addresses the problem of low utilization rate of jujube and sand date resources by developing fruit wine products through compound fermentation, thereby improving the comprehensive utilization rate of jujube and sand date raw materials, expanding their deep processing and utilization pathways, increasing product added value, and enriching the types of fruit wine products.

[0018] (2) This invention uses a combination of red dates and sand dates as raw materials, and combines brewing yeast and wine co-fermentation to make full use of the sugars, phenols, amino acids and other nutrients and flavor precursors in the two raw materials, promote the transformation of multiple substances during fermentation, improve the flavor quality and antioxidant capacity of the fruit wine, and promote the generation of volatile aroma substances such as alcohols and esters during fermentation, giving the fruit wine a rich fruit aroma and a harmonious fermentation aroma, and improving the overall flavor quality of the product.

[0019] (3) This invention introduces *Oenococcus oeni* during the fermentation process. *Oenococcus oeni* has strong tolerance to stress environments such as low pH, high ethanol, and SO2, and is often used in malolactic fermentation. Malolactic fermentation is an important biological acid reduction process in fruit wine brewing. Lactic acid bacteria can convert L-malic acid to L-lactic acid through malate-lactic acid enzymes, thereby reducing acidity and improving the harmony of the wine. In addition to biological acid reduction, lactic acid bacteria can also regulate the formation of aroma substances through metabolic activities, promote the enhancement of aroma characteristics such as fruit and floral aromas, and improve the body structure and aftertaste of fruit wine.

[0020] (4) This invention utilizes a blend of jujube and jujube as raw materials, and employs brewing yeast and *Saccharomyces cerevisiae* for synergistic fermentation to regulate the transformation of multiple components. The introduction of *Saccharomyces cerevisiae* for malic-lactic acid fermentation allows for a more complete conversion of malic acid to lactic acid, significantly altering the composition of organic acids. Simultaneously, it promotes the release and transformation of some bound phenolic substances, thereby improving raw material utilization. Compared to fermentation using only jujube or jujube as raw materials, the blend of jujube and jujube enables the complementarity of nutrients and metabolic substrates. Furthermore, the fermentation process promotes the generation of volatile aroma compounds such as alcohols and esters, endowing the fruit wine with richer fruit and fermentation aromas, resulting in a more harmonious flavor profile and improved overall quality.

[0021] (5) The brewing method of red date and sand date wine provided by the present invention has clear operation steps, wide source of raw materials, and is suitable for the preparation and production of compound fruit wine, and has certain industrial application value. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a comparison chart of the reducing sugar content of Example 1 and Comparative Examples 1-4 in this invention; Figure 2 This is a pH comparison chart of Example 1 and Comparative Examples 1-4 in this invention; Figure 3 This is a comparison chart of the total acid content of Example 1 and Comparative Examples 1-4 in this invention; Figure 4 This is a comparison chart of the alcohol content of Example 1 and Comparative Examples 1-4 in this invention; Figure 5 This is a comparison chart of the total phenol content of Example 1 and Comparative Examples 1-4 in this invention; Figure 6 This is a comparison chart of the total flavonoid content in Example 1 and Comparative Examples 1-4 of the present invention; Figure 7 This is a comparison chart of DPPH removal rates between Example 1 and Comparative Examples 1-4 in this invention; Figure 8 This is a comparison chart of ABTS clearance rates in Example 1 and Comparative Examples 1-4 of this invention; Figure 9This is a comparison chart of chromaticity values ​​between Example 1 and Comparative Examples 1-4 in this invention, where L* represents lightness, a* represents the red-green axis parameter, and b* represents the yellow-blue axis parameter.

[0024] Figures 1-9 The significance markers for multiple comparisons were a, b, c, d, ab, and bc. At the p-value < 0.05 level, different lowercase letters indicated significant differences between groups, while the same lowercase letter indicated no significant differences between groups.

[0025] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention proposes a jujube and jujube fruit wine and its brewing method, aiming to solve the problems of limited development of jujube and jujube products and low resource utilization.

[0028] Example 1: This embodiment describes a method for brewing jujube and red date wine, which includes the following steps: Step S1: Select red dates and sand dates free from mold and pests, wash them, remove the pits, and cut them into pieces for preparation; mix the ingredients according to the weight ratio of red dates and sand dates of 1:1, then add water and boil for 50 minutes, with a material-to-liquid ratio of 1:5 (g:mL), filter through gauze, and cool to 36-40°C to obtain the liquid for later use. Step S2: Add 0.3 g / L of pectinase to the liquid, enzymatically hydrolyze at 45°C for 4 hours, filter and set aside; add DL-malic acid to adjust the pH to 4.0, add white sugar to adjust the sugar content of the juice to 18°Bx, and add 40 mg / L of SO2. Step S3: Then add activated brewing yeast at 0.5% of the fermentation liquid volume and activated *Coccus faecium* at 1.6% of the fermentation liquid volume, and ferment at 25°C for 7 days; the *Coccus faecium* was purchased from the China Industrial Microbial Culture Collection Center (CICC), with accession number CICC6066.

[0029] Step S4: After fermentation, centrifuge at 8000 r / min for 10 min at 4℃ to obtain fruit wine.

[0030] Example 2: In this embodiment, a method for brewing jujube and jujube fruit wine is described, wherein the pH is adjusted to 3.6 by DL-malic acid, and the remaining steps and conditions are the same as in Example 1.

[0031] Example 3: In this embodiment, a method for brewing jujube and jujube fruit wine is described, wherein the pH is adjusted to 4.4 by DL-malic acid, and the remaining steps and conditions are the same as in Example 1.

[0032] Example 4: In this embodiment, a method for brewing jujube and sand date wine is described, wherein the sugar content of the fruit juice is adjusted to 15°Bx, and the remaining steps and conditions are the same as in Embodiment 1.

[0033] Example 5: In this embodiment, a method for brewing jujube and jujube fruit wine is described, wherein the sugar content of the fruit juice is adjusted to 21°Bx, and the remaining steps and conditions are the same as in Embodiment 1.

[0034] Example 6: In this embodiment, a method for brewing jujube and jujube fruit wine is described, wherein the amount of brewing yeast inoculated is adjusted to 0.3%, and the remaining steps and conditions are the same as in Example 1.

[0035] Example 7: In this embodiment, a method for brewing jujube and jujube fruit wine is described, wherein the amount of brewing yeast inoculated is adjusted to 0.7%, and the remaining steps and conditions are the same as in Example 1.

[0036] Example 8: In this embodiment, a method for brewing jujube and jujube fruit wine is described, wherein the inoculation amount of tartrazine is adjusted to 1.0%, and the remaining steps and conditions are the same as in Example 1.

[0037] Example 9: In this embodiment, a method for brewing jujube and jujube fruit wine is described, wherein the inoculation amount of tartrazine is adjusted to 2.2%, and the remaining steps and conditions are the same as in Example 1.

[0038] Comparative Example 1: In Comparative Example 1, the fermentation operation in step S3 was omitted, i.e., the mixed fruit juice stock solution with adjusted composition was prepared, and the remaining steps and conditions were the same as in Example 1.

[0039] Comparative Example 2: In Comparative Example 2, only Saccharomyces cerevisiae was inoculated during the fermentation process, without Saccharomyces cerevisiae, and the remaining steps and conditions were the same as in Example 1.

[0040] Comparative Example 3: In Comparative Example 3, only red dates were used as raw materials, and the remaining steps and conditions were the same as in Example 1.

[0041] Comparative Example 4: In Comparative Example 4, only jujubes were used as raw materials, and the remaining steps and conditions were the same as in Example 1.

[0042] The advantages of the method of the present invention in fruit wine brewing were evaluated by measuring the physicochemical indicators related to fruit wine quality of the samples prepared in Examples 1-9 and Comparative Examples 1-4. The specific measurement methods are as follows: 1. Determination of basic physicochemical indicators Alcohol content, reducing sugar, and total acid were determined according to GB / T15038-2006 "General Analytical Methods for Wines and Fruit Wines"; soluble solids were determined using a handheld refractometer; pH was measured directly using a pH meter. The color of the samples was characterized by measuring the CIE-Lab color parameters (L*, a*, b*) using a colorimeter under the CIED65 standard light source and a 10° standard observer angle; where L* represents lightness, a* is the red-green axis parameter, and b* is the yellow-blue axis parameter.

[0043] 2. Sensory evaluation The sensory evaluation of the red date and jujube fruit wine was conducted by a tasting panel of 20 professional judges (10 women and 10 men) who evaluated the wine in four aspects: appearance (0-20), aroma (0-35), taste (0-30), and typicality (0-15). The sensory scores of the jujube wine were obtained according to the evaluation criteria in Table 1.

[0044] Table 1 Sensory Evaluation Scoring Criteria for Jujube and Jujube Fruit Wine

[0045] 3. Determination of total phenol content Mix 0.5 mL of the sample with 2.5 mL of 10% Folin-Schockateol reagent and react at room temperature in the dark for 3 minutes. Then, add 2 mL of 7.5% Na₂CO₃ solution (w / v) to the mixture and let it stand at room temperature in the dark for 1 hour. Detect the absorbance at 765 nm using a microplate reader. Results are expressed as gallic acid equivalents (GAE), in mgGAE / 100 mL.

[0046] 4. Determination of total flavonoids Mix 0.5 mL of 50 g / L NaNO₂ with 4 mL of sample and react in the dark for 5 minutes. Then, add 1 mL of 100 g / L AlCl₃ to the mixture, stir well, and react in the dark for 5 minutes. Afterward, add 2 mL of 2 mol / L sodium hydroxide to the mixture and incubate in the dark for 10 minutes. Measure the absorbance at 510 nm using a microplate reader. The results are expressed as rutin equivalents (RE) in mgRE / L.

[0047] 5. Determination of ABTS's ability to scavenge cationic free radicals Equal volumes of K₂S₂O₈ solution (2.45 mmol / L) and ABTS stock solution (7 mmol / L) were mixed and allowed to stand at room temperature in the dark for 16 hours. When the absorbance of the mixture at 734 nm was 0.70 ± 0.02, it was diluted with anhydrous ethanol. Then, 0.6 mL of the sample was mixed with 5.4 mL of ABTS working solution and allowed to stand in the dark for 6 minutes. Distilled water was used as a blank control. The absorbance at 734 nm was measured using a UV-Vis spectrophotometer. The results were calculated using the following formula and expressed as the scavenging rate of ABTS against free radicals: ; in, A 0 This is the absorbance of the ABTS solution without a sample. A 1 It measures the absorbance of the sample after it reacts with the ABTS solution.

[0048] 6. Determination of DPPH free radical scavenging ability 2.0 mL of the sample and 2.0 mL of a 0.2 mM DPPH-ethanol solution were mixed at 25°C in the dark. Measurements were taken at 517 nm after 30 minutes. The DPPH radical scavenging rate was calculated using the formula:

[0049] in, A a This is the absorbance of the DPPH solution without a sample. A b It measures the absorbance of the sample after it reacts with the DPPH solution. A c It is the absorbance of the test sample after it is mixed with ultrapure water.

[0050] 7. Determination of the content of organic acids and phenolic compounds The contents of organic acids and phenolic compounds in the samples were determined by liquid chromatography-tandem mass spectrometry (LC-MS / MS). The instrument system consisted of an ultra-high performance liquid chromatograph (ACQUITY, Waters, USA) and a triple quadrupole mass spectrometer (ABSciex 4500, USA), with a C18 column (2.1 mm × 50 mm, 1.8 μm, Agilent Technologies, USA).

[0051] Sample and standard curve preparation: The internal standard solution was prepared using a 75% methanol aqueous solution to a final concentration of 250 ng / mL. The mixed standard working solution was mixed with 75% methanol aqueous solution containing the internal standard at a 1:1 (v / v) ratio, and then serially diluted to prepare a series of standard curve solutions. Samples were analyzed after adding the internal standard using the same method.

[0052] The sample pretreatment method is as follows: Take 100 μL of sample, add 300 μL of methanol-water solution, vortex mix for 60 s, centrifuge at 17000×g for 15 min, and take the supernatant for analysis.

[0053] The specific experimental steps are as follows: Take 1 μL of sample supernatant and place it on the instrument for mass spectrometry detection.

[0054] Chromatographic conditions: column temperature 40℃, injection volume 1μL; mobile phase A was 0.1% formic acid aqueous solution, and mobile phase B was acetonitrile.

[0055] Mass spectrometry analysis was performed using electrospray ionization (ESI) and multiple reaction monitoring (MRM) modes for quantitative analysis. The ion source parameters were set as follows: ion source drying gas temperature 500℃, curtain gas 25psi, collision gas 10psi, spray voltage 4500V, and nebulization temperature 500℃.

[0056] Data processing was performed using MultiQuant 3.0.3 software. A standard curve was plotted using the standard response and its corresponding concentration to calculate the sample concentration.

[0057] 8. Determination of free amino acid content A fully automated amino acid analyzer (Biochrom30+, Biochrom Ltd., UK) was used. 1 mL of sample was added to a 5% sulfosalicylic acid solution at a 1:1 ratio and mixed thoroughly. The mixture was centrifuged at 6200×g for 10 min. 1 mL of the supernatant was filtered through a 0.22 μm membrane and fed into the analyzer. The amino acid was detected using a post-column ninhydrin derivatization method.

[0058] Amino acid analyzer conditions: citrate buffer B1 (pH 3.2), B2 (pH 4.25), B5 (pH 6.45), buffer flow rate 25 mL / h, reaction flow rate 10 mL / h, separation column: Na-type cation exchange resin column (200 × 4.6 mm, 8 μm), detection wavelengths 570 nm and 440 nm; column temperature gradient program: initial temperature 44℃, hold for 10 min, increase to 47℃, hold for 13 min, then increase to 98℃, hold for 26 min; reaction chamber temperature 138℃, injection volume 20 μL.

[0059] 9. Determination of volatile organic compounds (VOCs) Volatile organic compounds (VOCs) were detected using headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS). The specific procedure was as follows: 5 mL of wine sample was placed in a headspace vial, 20 μL of 25 μg / mL 2-octanol internal standard and 1 g NaCl were added, and the mixture was shaken at 250 rpm for 5 minutes at 80 °C. The SPME extraction probe was then inserted into the headspace vial, and extraction was performed at 60 °C for 40 minutes. Desorption was then performed by inserting the extraction needle into the GC inlet at 250 °C for 5 minutes.

[0060] Chromatographic column: 19091S-433HP-5MS (30m×0.25mm×0.25μm); Carrier gas: High-purity He (99.999%); Flow rate: 1.0mL / min; Injection mode: Split injection, split ratio: 5:1; Gas phase temperature program: Initial value: 40℃, hold for 3 min; Increase from 40℃ to 80℃ at a rate of 5℃ / min, hold for 0 min; Increase from 80℃ to 220℃ at a rate of 10℃ / min, hold for 2 min; Increase from 220℃ to 320℃ at a rate of 30℃ / min, hold for 5 min. EI ion source: Positive polarity, electron energy: 70eV; Ion source temperature: 240℃, quadrupole temperature: 160℃; Mass scan range: 25-500m / z; Scan rate: 1562u / s, frequency: 2.7 (scans / s), step size: 0.1m / z. Compound identification was based on comparison of the obtained mass spectra with the NIST 2020 library. Qualitative analysis included spectral matching and retention index verification. Volatile compounds were quantified based on peak area relative to an internal standard, calculated as follows: ; in: x For unknown compound concentrations, A The peak area of ​​the compound. c The concentration of the internal standard (2-octanol) A ’ This represents the peak area of ​​the internal standard.

[0061] The above experimental methods were used to test Examples 1-9 and Comparative Examples 1-4, and the experimental test results are shown below: Table 2. Indicators of Jujube and Jujube Fruit Wine from Examples 1-9

[0062] Note: - indicates no detection. As shown in Table 2, the jujube and red date wines prepared using the method of this invention all exhibited good sensory quality. Specifically, Examples 1 and 3 had relatively high pH values ​​and lower total acid content than other examples, indicating that acidification conditions have a certain influence on the acidity characteristics of the wine. Example 5 had a higher alcohol content than other groups, while Example 4 had a significantly lower alcohol content, demonstrating that initial sugar content has a significant impact on the alcoholic fermentation process and alcohol production. In Examples 6 and 7, the yeast inoculation amount differed from other groups, and in Examples 8 and 9, the *Coccus faecium* inoculation amount differed from other groups, with each group exhibiting superior quality. Example 1 was selected as the preferred embodiment of this invention from Examples 1-9. Various physicochemical indicators were tested on this preferred embodiment and Comparative Examples 1-4 to further verify the technical advantages of this invention.

[0063] Physicochemical indicators of Example 1 and Comparative Examples 1-4 were tested, and the basic physicochemical indicators of each group are shown in Table 2. Figures 1-9 As shown. Figure 1 As shown, by detecting the reducing sugar content of Example 1 and Comparative Examples 1-4, it was found that the reducing sugar content of Comparative Example 1 was higher than that of the other four groups, indicating that fermentation treatment can reduce the reducing sugar content. Figure 2 As shown, by measuring the pH values ​​of Example 1 and Comparative Examples 1-4, it was found that the pH values ​​of Example 1 and Comparative Examples 3 and 4 were all higher than those of Comparative Example 1. Figure 3 As shown, by measuring the total acid content of Example 1 and Comparative Examples 1-4, it was found that the total acid content of Example 1 and Comparative Examples 3 and 4 was significantly lower than that of Comparative Example 1 (P<0.05). This may be because malolactic fermentation occurred during the fermentation process after the addition of *Coccus vinifera*. Figure 4 As shown, the alcohol content of the four groups was measured in Example 1 and Comparative Examples 1-4, and the alcohol content was between 7.94 and 8.10% vol, with no significant difference (P>0.05).

[0064] Phenolic compounds are important active substances in fruit wine. For example... Figure 5 As shown, the total phenol content of Example 1 and Comparative Examples 1-4 was measured, and the total phenol content of Example 1 and Comparative Examples 1-4 was 179.03, 220.70, 172.86, 182.73, and 153.63 mg GAE / 100mL, respectively. The total phenol content of the fermentation treatment groups was lower than that of Comparative Example 1. This may be because phenolic compounds are oxidized during the brewing process, leading to a decrease in the total phenol content in the treatment groups. The total phenol content of Example 1 after MLF was higher than that of Comparative Example 2, possibly due to the hydrolysis of bound phenols into free forms by β-glucosidase and esterase secreted by *C. tumefaciens*, and the increased pH after malolactic fermentation leading to increased solubility of condensed tannins, thus enhancing their dissolution.

[0065] like Figure 6 As shown, the total flavonoid content of Examples 1 and Comparative Examples 1-4 was detected, and it was found that the total flavonoid content of each group fluctuated between 168.63 and 721.99 mgRE / L. It was observed that the total flavonoid content decreased after alcoholic fermentation and decreased after MLF. In addition, the total flavonoid content of Comparative Example 1, Example 1, and Comparative Example 2 was significantly higher than that of Comparative Example 3 and Comparative Example 4 (P<0.05). This may be related to the interaction between different plant matrices in the compound fruit juice system.

[0066] The antioxidant activity of Examples 1 and Comparative Examples 1-4 was evaluated using DPPH and ABTS free radical scavenging capacity assays. Figure 7 As shown, Comparative Example 1 exhibited the highest DPPH scavenging rate (67.01%, P<0.05), significantly higher than the treatment group. In contrast, Comparative Example 3 had the lowest DPPH activity, while Example 1 after MLF fermentation showed an increase compared to Comparative Example 2, which underwent simple alcohol fermentation.

[0067] like Figure 8 As shown, the results of the ABTS free radical scavenging ability test showed that, compared with Comparative Example 1, fermentation caused the ABTS free radical scavenging rate of each group to decrease to varying degrees. Among them, Comparative Example 3 had the lowest ABTS scavenging rate. The scavenging rates of each group fluctuated between 48% and 80.73%. The scavenging rate of Example 1 was lower than that of Comparative Example 2. This phenomenon may be related to the degradation and transformation of active phenolic substances and the metabolic effects of microorganisms during fermentation.

[0068] like Figure 9 As shown, compared with Comparative Example 1, the L*, a*, and b* values ​​of each group all showed an increasing trend. An increase in L* value indicates increased brightness of the fruit wine, while increases in a* and b* values ​​indicate enhanced red and yellow hues. This suggests that as fermentation progresses, the colors of each group gradually tend towards brighter red and yellow tones. Comparative Example 4 showed significantly higher L* and b* values ​​than the other groups, indicating it was brighter and more yellow. However, there was no significant color difference between Example 1 and Comparative Example 2 (P>0.05).

[0069] Table 3. Results of organic acid content detection in Example 1 and Comparative Examples 1-4

[0070] Note: ND indicates not detected. Organic acids are closely related to biological metabolic activities during fermentation, serving as raw materials for cellular redox reactions and the tricarboxylic acid cycle, and undergoing interconversion during alcoholic and malolactic fermentation. Table 3 shows that microbial fermentation significantly alters the content and composition of organic acids in the fruit juice. Compared to Comparative Example 1, the citric acid content in Comparative Example 2, after alcoholic fermentation, decreased. After malolactic fermentation, the citric acid content in Example 1 further decreased to 985.18 mg / L, while the citric acid contents in Comparative Examples 3 and 4 were 683.58 mg / L and 857.18 mg / L, respectively. The decrease in citric acid content may be related to the utilization of citric acid by *Saccharomyces cerevisiae* and *Saccharomyces cerevisiae* during fermentation. Simultaneously, their metabolic processes may also generate lactic acid, diacetyl, 2,3-butanediol, and other substances, further affecting the composition of organic acids in the fermentation system.

[0071] The L-malic acid content in Comparative Example 1 was 580.86 mg / L, while in Comparative Example 2 it increased to 637.91 mg / L after alcoholic fermentation. This phenomenon may be related to yeast-mediated organic acid metabolism and the release of bound organic acids during fermentation. During alcoholic fermentation, yeast metabolism, plant cell wall degradation, and ethanol production enhance the system's solubility, which may promote the release of originally bound L-malic acid, thus leading to an increase in the detected content.

[0072] However, after MLF fermentation, the L-malic acid content in Example 1 decreased to 359.91 mg / L, while that in Comparative Examples 3 and 4 were 447.07 mg / L and 284.17 mg / L, respectively. This is mainly because *C. tumefaciens* can decarboxylate L-malic acid to L-lactic acid, thereby reducing the L-malic acid content in the system. As the main product of MLF, the L-lactic acid content increased in all fermentation groups. The L-lactic acid content in Comparative Example 1 was only 7.65 mg / L, while that in Comparative Example 2 increased to 58.27 mg / L; after MLF, the L-lactic acid content in Examples 1, Comparative Examples 3, and Comparative Examples 4 further increased to 347.55 mg / L, 323.82 mg / L, and 346.39 mg / L, respectively. The simultaneous decrease in L-malic acid and increase in L-lactic acid indicates that the MLF process was successful.

[0073] The tartaric acid contents of Comparative Example 1, Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were 4.39, 5.22, 4.07, 7.33 and 2.87 mg / L, respectively. The tartaric acid contents of each group changed little, indicating that tartaric acid has high stability during fermentation.

[0074] The benzoic acid contents were 22.49, 17.10, 14.64, 28.65, and 0 mg / L, respectively. Compared with Comparative Example 1, the fumaric acid content in all groups decreased significantly after fermentation. As an important intermediate metabolite in the TCA cycle, fumaric acid may further participate in the conversion of other organic acids during fermentation, thus its content decreased.

[0075] Conversely, succinic acid content increased during fermentation. Comparative Example 1 had the lowest succinic acid content, at only 15.47 mg / L, while Examples 1 and 2 increased to 202.85 mg / L and 203.22 mg / L, respectively, and Comparative Examples 3 and 4 had contents of 196.43 mg / L and 200.86 mg / L, respectively. Succinic acid is one of the important metabolites in yeast alcoholic fermentation, and its formation is closely related to the TCA cycle, amino acid metabolism, and yeast nitrogen source utilization. Therefore, the large accumulation of succinic acid after fermentation may mainly originate from enhanced yeast metabolic activity.

[0076] Table 4. Detection results of phenolic substance content in Example 1 and Comparative Examples 1-4.

[0077] Note: ND indicates not detected. Phenolic compounds are important functional and flavor-related components in fruit wines. Different fermentation methods and raw material compositions significantly affect the content of phenolic compounds. As shown in Table 5, the fermentation process alters the composition and distribution of phenolic substances, leading to a decrease in the content of some phenolic compounds and a significant increase in the content of others. The content of 11 phenolic compounds in each sample group was detected using LC-MS / MS technology. These 11 phenolic compounds include coumaric acid, ferulic acid, syringic acid, protocatechuic acid, catechin, epicatechin, quercetin, quercetin, vanillic acid, gallic acid, and rutin. Epicatechin, quercetin, and rutin were not detected in Comparative Example 4.

[0078] Both p-coumaric acid and ferulic acid showed a decreasing trend after fermentation. In Comparative Example 1, the contents of p-coumaric acid and ferulic acid were 970.69 μg / L and 842.95 μg / L, respectively. Compared with Comparative Example 1, the contents of p-coumaric acid in Example 1 and Comparative Example 2 decreased to 432.53 μg / L and 269.97 μg / L, respectively, and the contents of ferulic acid decreased to 741.40 μg / L and 533.01 μg / L, respectively. The contents of both p-coumaric acid and ferulic acid in Comparative Example 3 were lower than those in Comparative Example 4. Both p-coumaric acid and ferulic acid belong to hydroxycinnamic acids (HCAs) and can serve as important substrates in the metabolic processes of *C. sacchariformis*. Studies have shown that some *C. sacchariformis* strains possess cinnamoyl esterase activity, which can promote the release of bound hydroxycinnamic acid during malolactic fermentation, thereby increasing the contents of free p-coumaric acid and ferulic acid in the system.

[0079] Syringic acid and vanillic acid increased significantly after fermentation. During winemaking, yeast releases anthocyanins (i.e., anthocyanins) – dimethicone and paeoniflorin – and promotes their decomposition into syringic acid and vanillic acid, respectively. Compared with Comparative Example 1, the vanillic acid content in Examples 1 and Comparative Examples 2-3 was increased. Meanwhile, the ferulic acid content showed a decreasing trend, suggesting that some ferulic acid may have been converted into vanillic acid through microbial metabolic pathways during fermentation.

[0080] Catechins, epicatechin, and quercetin generally decreased after fermentation. Flavanols are another important subclass of flavonoids, possessing a flavan core structure. The main members found in grapes and wines are (+)-catechins and (-)-epicatechins. The decrease in catechins and epicatechins after alcoholic fermentation may be related to their participation in acetaldehyde-mediated polymerization. These flavanols can condense with anthocyanins or other flavanols to form polymeric tannins and polymeric pigments, leading to a decrease in the content of free catechins and epicatechins. Flavonols are an important subclass of flavonoids, and quercetin is one of them. The most significant decrease in quercetin was observed in the group compared to Comparative Example 1 (1454.16 μg / L) to Example 1 (326.10 μg / L).

[0081] Protocatechuic acid and gallic acid were the main phenolic acids in the samples. The content of protocatechuic acid showed little variation in Comparative Example 1, Example 1, and Comparative Example 2, while the content differed significantly in Comparative Example 3 and Comparative Example 4, indicating that the content of protocatechuic acid in the jujube and red date compound formula was more stable compared to Comparative Example 1. The gallic acid content remained consistently high, suggesting that red date may be an important source of gallic acid.

[0082] Quercetin and rutin showed a clear raw material dependence among different samples. Quercetin and rutin were not detected in Comparative Example 4, while the rutin content in Comparative Example 3 was as high as 8088.73 μg / L, far exceeding that of Example 1 (1502.12 μg / L) and Comparative Example 1 (2244.38 μg / L). This result suggests that rutin and quercetin may mainly originate from jujube raw materials.

[0083] Table 5. Results of free amino acid content detection in Example 1 and Comparative Examples 1-4

[0084] Free amino acids have a significant impact on the flavor of fruit wine, not only providing a source of nitrogen compounds necessary for microbial reproduction but also serving as flavor precursors. Table 5 shows that a total of 17 amino acids were identified, including 8 essential amino acids (lysine, phenylalanine, methionine, threonine, isoleucine, leucine, valine, and histidine) and 9 non-essential amino acids. The total amino acid content measured in Comparative Example 1 was 2204.99 μg / mL, with the main free amino acids detected being Pro, Ser, Tyr, Arg, and Phe; the total amino acid content measured in Example 1 was 1222.12 μg / mL, with the main free amino acids detected being Pro, His, Phe, Tyr, and Cys; the total amino acid content measured in Comparative Example 2 was 1139.29 μg / mL, with the main free amino acids detected being Pro, His, Phe, Tyr, and Cys; the total amino acid content measured in Comparative Example 3 was 1590.79 μg / mL, with the main free amino acids detected being Pro, Tyr, Cys, Lys, and Phe; and the total amino acid content measured in Comparative Example 4 was 474.43 μg / mL, with the main free amino acids detected being His, Phe, Tyr, Pro, and Cys.

[0085] Both Example 1 and Comparative Example 2 showed a significant decrease in amino acid content after fermentation. Compared with Comparative Example 1, Ser content decreased by 97.14% and 97.48%, Arg content decreased by 94.40% and 90.21%, Asp content decreased by 92.23% and 94.74%, Tyr content decreased by 85.65% and 88.01%, and Glu content decreased by 84.04% and 88.12%, respectively. Many volatile aroma compounds are related to the amino acid composition of fruit juice. During fermentation, brewer's yeast consumes a large amount of amino acids, converting them into secondary metabolites, which explains the decrease in amino acid content during fruit wine fermentation. The metabolic pathway of amino acids in fruit wine mainly involves two steps. First, branched-chain keto acids are converted into aldehydes by decarboxylases, and then these aldehydes are further converted into alcohols by alcohol dehydrogenases. Second, higher alcohols combine with fatty acid acyl-CoA to form esters by acyltransferases; in addition, phosphotransferases can also catalyze the conversion of higher alcohols into acids. According to literature, based on their taste characteristics, 17 free amino acids (FAAs) are divided into four flavor groups: umami / sour (Asp, Glu), sweet (Ala, Lys, Thr, Pro, Ser, Gly), bitter (Phe, Arg, Ile, Leu, His, Tyr, Met, Val), and tasteless (Cys). The proportions of sweet amino acids in Comparative Example 1, Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 were 63.37%, 78.65%, 79.31%, 92.1%, and 20.67%, respectively. Compared to Comparative Example 1, the proportions of sweet amino acids in Comparative Example 2 and Example 1 were higher, indicating that even small changes in amino acid concentration can significantly affect the formation of aromatic compounds.

[0086] Table 6. Detection results (μg / L) of volatile substances in Example 1 and Comparative Examples 1-4.

[0087] Note: ND indicates not detected. Aroma is a key indicator for evaluating the quality of fruit wine. Headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) was used to analyze the volatile organic compounds (VOCs) in five samples. As shown in Table 6, a total of 80 VOCs were identified in the samples, including 25 alcohols, 21 esters, 20 aldehydes and ketones and related carbonyl compounds (including furans, lactones and heterocyclic derivatives, hereinafter referred to as aldehydes and ketones), and 14 acids.

[0088] Alcohols are secondary metabolites of yeast, synthesized through glycolysis or the dehydrogenation and decarboxylation of amino acids. Their content is affected by the availability of sugars and amino acids. Fermentation significantly alters the composition of alcohol compounds in fruit juice. Compared to Comparative Example 1, all fermentation groups showed a significant increase in higher alcohols and aromatic alcohols. Studies have shown that Saccharomyces cerevisiae can utilize tyrosine to generate higher concentrations of tyrosol via the Ehrlich pathway. The results indicated that a total of 25 alcohols were detected. Compared to Comparative Example 1, the content of phenylethanol in the fermentation groups was significantly increased, with Example 1 showing the highest content. Phenylene alcohol has distinct rose and honey aroma characteristics and is an important contributor to the aroma of fruit wine. α-Methylbenzyl alcohol reached 47106.59 μg / L in Example 1, exhibiting floral and sweet aroma characteristics, and synergistically enhanced the complexity of the fruit aroma with phenylethanol.

[0089] Branched-chain higher alcohols were significantly increased in the fermentation groups. Compared to Comparative Example 1, 2-methyl-1-propanol was detected in all other groups, with Example 1 and Comparative Example 4 showing higher levels of 2-methyl-1-propanol, which may be related to the degradation of valine during yeast fermentation. However, higher alcohols can enhance the complexity of the wine at appropriate concentrations, while excessive accumulation may produce pungent alcoholic odors. Although the higher concentration of higher alcohols in the Example 1 group was higher, concentrations below 300 mg / L could add ideal complexity to the wine, while concentrations above 400 mg / L could have adverse effects, thus potentially adding overall sensory complexity to the fruit wine. Glycerol was detected in Example 1, Comparative Example 3, and Comparative Example 4 groups. Glycerol is a major product of alcoholic fermentation. Although these triols do not directly affect the aroma characteristics of the wine, glycerol can significantly affect the apparent sweetness of the wine depending on its concentration and type. Overall, fermentation significantly promoted the production of aromatic alcohols, especially the accumulation of phenethyl alcohol, which significantly enhanced the floral characteristics of the fruit wine, while the increase in branched-chain higher alcohols reflects enhanced amino acid metabolism.

[0090] Esters are among the most important aroma components in fruit wines. Esters with low perception thresholds are highly volatile and can exhibit sweet, fruity, and floral aromas even at low concentrations. Generally, esters are mainly produced through yeast biosynthesis, a process involving the hydrolysis of short-chain fatty acids by esterases and the catalytic reaction of acetyl-CoA with alcohols by alcohol acetyltransferases to synthesize acetates. Twenty-one esters were detected across the various groups. Compared to Comparative Example 1, fermentation significantly promoted the formation and accumulation of ester compounds. Comparative Example 1 only detected a few esters, including allyl acetate, 2-octyl acetate, 1,6-heptadien-4-ol acetate, and methyl hexadecanoate, and their contents were low, indicating a relatively simple ester composition in the raw fruit juice. After fermentation, the types and contents of esters in all treatment groups significantly increased, indicating that microbial metabolism significantly enhanced esterification reactions and promoted the formation of aroma compounds. Ethyl esters of organic acids, ethyl esters of straight-chain fatty acids (with a relatively low proportion of ethyl esters of branched-chain fatty acids), and acetate esters of higher alcohols also largely determine the fruity aroma of wine, and these aromas are particularly prominent in newly brewed wines.

[0091] Ethyl octanoate was present in the highest concentration in Example 1. Ethyl octanoate belongs to the C6–C10 fatty acid ethyl ester volatiles and is an important fruity aroma compound in fermented wines, exhibiting a distinct fruity aroma. Its formation is related to the hydrolysis of short-chain fatty acids by esterases and the reaction of acetyl-CoA with alcohols catalyzed by alcohol acetyltransferases to synthesize acetate esters. Lactic acid bacteria can produce or alter compounds affecting aroma through their own metabolism. In contrast, ethyl lactate was significantly elevated in Example 1, Comparative Example 3, and Comparative Example 4, far exceeding that in Comparative Example 2, where ethyl lactate was the most abundant aroma compound produced during malolactic fermentation. The formation of ethyl lactate is associated with the formation of lactic acid, and its synthesis amount can be correlated with the degradation rate of malic acid.

[0092] Aromatic esters also exhibited a significant fermentation response. Ethyl phenylpropionate reached a concentration of 98.66 μg / L in Example 1, higher than in Comparative Examples 2 and 3. Ethyl phenylpropionate contributes distinct floral and honey aromas to the wine. Furthermore, 2-phenylethyl acetate reached a concentration of 446.70 μg / L in Example 1, significantly higher than in Comparative Examples 2 and 3. These compounds typically possess honey, fruit, and floral aromas and are important components in enhancing the aroma complexity of fruit wines.

[0093] Aldehydes are formed through the transamination or decomposition of amino acids. Due to the presence of the carbonyl group, they are chemically relatively reactive and easily reduced to alcohols or oxidized to acids. Although the concentration of aldehydes in fruit wine is low, their odor detection threshold is low, playing an important role in the fresh herbal aroma.

[0094] Comparative Example 1 detected high levels of hydroxyacetaldehyde, methylglyoxal, 3-furfural, and various aromatic aldehydes, indicating significant sugar degradation and Maillard reaction-related transformations during the fruit juice boiling process at 100℃. Methylglyoxal, a key early intermediate in the Maillard reaction, mainly originates from the further decomposition of hexose cleavage and Amadori rearrangement products, and can further participate in the Strecker degradation reaction to generate more complex aroma precursor compounds. Meanwhile, furfural, a caramelization and functional intermediate molecule in heated foods, is typically formed from the decomposition of pentoses or hexoses or the further interaction of these sugars with amino acids, imparting certain caramel and roasted aroma characteristics to the sample.

[0095] As fermentation progressed, most heat-processing-related aldehydes and ketones significantly decreased or even disappeared in the fermentation samples, indicating that yeast and *C. tumefaciens* may further utilize these intermediates through metabolic transformation or reduction reactions, thereby reducing their residual levels in the final product. In contrast, phenylacetaldehyde was detected in all groups, with the highest content in Example 1, significantly higher than in Comparative Examples 2-4. Phenylacetaldehyde mainly originates from the degradation products of phenylalanine via the Ehrlich pathway and is a typical aromatic amino acid metabolic intermediate with distinct honey characteristics, making a significant contribution to the overall aroma quality of fruit wine. Furthermore, some furans and lactones (such as 5-methyl-2-furanaldehyde and 5-hexyldihydro-2(3H)-furanone) were mainly detected in the fermentation group, possibly because microbial metabolism further enriched the aroma composition on the basis of heat processing. The heat treatment stage of the juice promoted sugar degradation and the formation of Maillard reaction-related carbonyl compounds, and endowed the juice with certain caramelization and toasting aroma characteristics. The fermentation process alters the composition of volatile components through microbial metabolism and transformation, promoting the formation of fermentation-type aroma substances with floral characteristics, such as phenylacetaldehyde, and driving the evolution of fruit wine aroma characteristics from heat-processed to fermentation-type flavor.

[0096] Acidic substances primarily originate from the fruit itself. They are not only considered aroma compounds but also defined as aroma precursors, synthesized through various biological reactions. Comparative Example 1 mainly detected benzoic acid, hexanoic acid, heptanoic acid, and acetic acid, among other raw material-derived acids. However, the acid composition changed significantly after fermentation, with some original acids decreasing and new metabolism-related acids being generated. Octyl acid was detected in all groups, with higher levels in Example 1 and Comparative Example 4. As an important precursor for the synthesis of fatty acid ethyl esters, it can be converted into octanoate ethyl ester. Overall, fermentation altered the acid composition of the fruit wine, promoting the formation of flavor-related acids.

[0097] As demonstrated in Examples 1-9 and Comparative Examples 1-4, this invention utilizes a blend of jujube and sea buckthorn as raw materials, and employs brewing yeast and *Saccharomyces cerevisiae* for synergistic fermentation, achieving the regulation of multi-component material transformation. Through the detection of basic physicochemical indicators, sensory evaluation, total phenols, total flavonoids, organic acids and phenolic compounds, free amino acid content, ABTS, DPPH, and volatile organic compounds, it was verified from multiple dimensions that compared to fermentation using single jujube or sea buckthorn raw materials, the blend of jujube and sea buckthorn can achieve complementarity in nutrients and metabolic substrates. Simultaneously, the fermentation process promotes the generation of volatile aroma substances such as alcohols and esters, endowing the fruit wine with richer fruit and fermentation aromas, resulting in a more harmonious flavor profile and improved overall quality. The introduction of *Saccharomyces cerevisiae* for malic-lactic fermentation further facilitates the conversion of malic acid to lactic acid in the system, significantly altering the composition of organic acids and promoting the release and conversion of some bound phenolic substances, thereby improving the utilization rate of raw materials.

[0098] The above description is only a preferred embodiment of the present invention and does not limit the scope of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the protection scope of the present invention.

Claims

1. A method for brewing jujube and red date wine, characterized in that, Includes the following steps: Step S1: Select red dates and sand dates, wash them, remove the pits, cut them into pieces and prepare the ingredients. Add water and boil them, then filter them through gauze and cool them to obtain the liquid. The mass ratio of red dates to sand dates is 1:0.5-2. The ratio of raw materials to water in the liquid is 1:3-1:

7. Step S2: Add pectinase to the liquid for enzymatic hydrolysis, then add DL-malic acid to adjust the pH, add white sugar to adjust the sugar content of the juice, and add sulfur dioxide for sterilization and anti-oxidation. Step S3: Inoculate the activated brewing yeast and *Coccus faecium* into the liquid treated in step S2 to obtain a fermentation broth. The amount of brewing yeast inoculated is 0.3-0.7% of the fermentation broth volume, and the amount of *Coccus faecium* inoculated is 1.0-2.2% of the fermentation broth volume. Step S4: Centrifuge the fermentation liquid to obtain fruit wine.

2. The brewing method of jujube and red date wine according to claim 1, characterized in that, In step S3, fermentation specifically involves fermenting at a temperature of 20-30℃ for 6-8 days.

3. The brewing method for jujube and red date wine according to claim 1, characterized in that, The brewing yeast mentioned in step S3 is specifically Angel Fruit Wine Yeast, and the inoculation amount of Angel Fruit Wine Yeast is 0.5%.

4. The brewing method of jujube and red date wine according to claim 1, characterized in that, The inoculation amount of *Chlorella vulgaris* in step S3 is 1.6%.

5. The brewing method of jujube and red date wine according to claim 1, characterized in that, In step S1, the mass ratio of red dates and sand dates is 1:1; the ratio of raw materials to hot water is 1:

5.

6. The brewing method of jujube and red date wine according to claim 1, characterized in that, The boiling time in step S1 is 40-50 minutes, and the cooling temperature is 36-40°C.

7. The brewing method of jujube and red date wine according to claim 1, characterized in that, In step S2, the amount of pectinase added is 0.3 g / L, the enzymatic hydrolysis temperature is 45℃, and the enzymatic hydrolysis time is 4 h.

8. The brewing method of jujube and red date wine according to claim 1, characterized in that, In step S2, the pH is adjusted to 3.6-4.4; the sugar content of the fruit juice is adjusted to 15-21°Bx; and the amount of sulfur dioxide added is 40 mg / L based on the volume of the liquid.

9. The brewing method of jujube and red date wine according to claim 1, characterized in that, The centrifugation process in step S4 specifically involves centrifuging the fermentation broth for 10 minutes at 4°C and 8000 r / min.

10. A jujube and red date wine, characterized in that, It is prepared by the brewing method described in any one of claims 1-9.

Images