Fermentation brewing method for improving quality of red grape mousalaisis

Abstract

The invention relates to the technical field of grape wine, and discloses a fermentation brewing method for improving the quality of red grape mousse, which comprises the following steps: (1) preparing, cleaning and selecting, (2) juicing, precipitating and separating peel residues, (3) heating and concentrating, (4) adjusting components, (5) naturally fermenting, (6) terminating the fermentation, (7) clarifying and filtering, and (8) sterilizing to obtain a finished product. Finished wine is obtained; according to the preparation method disclosed by the invention, the content of phenolic substances in the red grape mousalaisis and the antioxidant activity of the red grape mousalaisis can be remarkably improved, and the economic value of the finished wine is greatly improved; the brewed wine body is bright in color, brick-red in color, full and harmonious in wine body, mellow in taste and distinct in typicality, and the quality and the oxidation resistance of mousalaisi can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of wine brewing, and in particular to a fermentation and brewing method for improving the quality of red grape moussalais. Background Art

[0002] Wine is one of the most important alcoholic beverages in the world, and its quality is determined by many factors, including grape varieties, climate conditions, soil types, cultivation measures, brewing techniques, and aging processes. Phenolic substances are an important factor affecting the quality of wine. These phenolic substances mainly come from grape skins and grape seeds, and enter the wine through the skin-dregs maceration process during the fermentation process. A large number of studies have shown that polyphenols help improve the taste and flavor of wine, stabilize the color of wine, and maintain aroma components. In addition to grape raw materials. During the brewing process, fermentation temperature, skin-dregs maceration time, skin-juice ratio adjustment and other brewing processes will affect the phenolic content in the finished wine.

[0003] Musalaisi wine is a delicious and mellow wine brewed by the Xinjiang Uygur people through the handcraft techniques handed down from generation to generation from local grapes, such as extracting juice, concentrating and naturally fermenting. Musalaisi is mainly brewed with Hetian red grapes as raw materials. In recent years, grape raw materials such as Krisun and Munag have been used to brew Musalaisi. Red grapes are rich in vitamins, minerals, amino acids, etc., and have a sweet taste and excellent taste. They are one of the most precious and commercially valuable representative varieties of fresh-eating grapes, but they have a low sugar content. When used to ferment fruit wine, they have a light taste and insufficient aroma. The application of red grapes in the production of Musalaisi can complement the deficiency of the single raw material for brewing Musalaisi. During the fermentation process of Musalaisi, the skin residue and grape juice are first boiled separately. When the sugar content of the skin residue boiled with water reaches 26-28°Bx, they are mixed and fermented. However, there are few studies on the effects of different treatments of the skin residue at different fermentation stages on the color, sensory quality and phenolic content of Musalaisi.

[0004] In order to solve the above problems, a fermentation brewing method for improving the quality of red grape moussalais is needed. Summary of the invention

[0005] The object of the present invention is to provide a fermentation brewing method for improving the quality of red grape moussalais.

[0006] The scheme of the present invention is:

[0007] A fermentation brewing method for improving the quality of red grape moussalais comprises the following steps:

[0008] 1) Prepare to wash and select red grapes that are fresh, mature, free of rot, deterioration, disease and insect pests;

[0009] 2) Juice extraction, precipitation and skin-dregs separation: the grapes are washed and fully squeezed and crushed, and the skin-dregs are separated by precipitation. The separated grape juice is immersed in low temperature for 20 to 30 hours, and the low temperature range is 10 to 15°C;

[0010] 3) heating and concentrating, mixing the separated skin residue with water and boiling until the sugar content of the juice reaches 11-13°Bx, filtering to remove residue, mixing the filtrate with the grape juice soaked in step 2) and boiling, detecting the sugar content during boiling, and when the sugar content reaches 25°Bx, the concentration is completed, cooling is performed to obtain concentrated juice;

[0011] 4) Ingredient adjustment: the total acid of the concentrated juice is adjusted to pH 3.7;

[0012] 5) Natural fermentation: the adjusted concentrated juice is sent to the fermentation tank, the amount of concentrated juice added is 75-85% of the capacity of the fermentation tank, and the natural fermentation is carried out at a fermentation temperature of 19-21°C, and the residual sugar content is tested every 24 hours;

[0013] 6) Terminate the fermentation. When the residual sugar content drops to 9-11°Bx, turn the can over, remove the sludge, separate the supernatant, add the terminator and cool the wine down. Monitor the changes in the wine and residual sugar every 8 hours until the residual sugar remains basically unchanged.

[0014] 7) clarifying and filtering, aging at 2°C for 2 weeks, during which time the cans are decanted 1-2 times, and filtering through a membrane to obtain red grape moussale;

[0015] 8) sterilizing and finishing the wine, sterilizing the red grape moussalis to obtain a finished wine.

[0016] As a preferred technical solution, the low-temperature immersion in step 2) is performed for 24 hours.

[0017] As a preferred technical solution, in the step 3), the skin residue is mixed with water at a mass ratio of 1:1.5; and the step of filtering and removing the residue uses gauze to filter and remove the residue.

[0018] As a preferred technical solution, the total acid in step 4) is adjusted using tartaric acid.

[0019] As a preferred technical solution, the amount of concentrated juice added in step 5) is 80% of the capacity of the fermentation tank.

[0020] As a preferred technical solution, the terminator in step 6) is 120 mg / L potassium metabisulfite.

[0021] As a preferred technical solution, the membrane in step 7) is a 0.45 um membrane.

[0022] As a preferred technical solution, the temperature is lowered to -10°C in step 6).

[0023] The present invention also discloses a fermentation brewing method for improving the quality of red grape moussalais, comprising the following steps:

[0024] 1) preparing, washing and selecting, selecting fresh, mature, non-rotten, non-deteriorated and pest-free red grapes; 2) juicing, precipitating and separating the skin and residue, washing the grapes and fully squeezing and crushing them, separating the skin and residue by precipitation, and soaking the separated grape juice at low temperature for 20 to 30 hours, the low temperature range is 10 to 15°C; 3) heating and concentrating, mixing the separated skin and residue with water and boiling, boiling until the sugar content of the juice reaches 11 to 13°Bx, filtering to remove residues, mixing the filtrate with the grape juice soaked in step 2) and boiling, detecting the sugar content during boiling, and when the sugar content is 25°Bx, the concentration is completed, cooling treatment is performed to obtain concentrated juice; 4) adjusting the ingredients, the total acidity of the concentrated juice Adjust the pH to 3.7; 5) Natural fermentation, the adjusted concentrated juice is sent to the fermentation tank, the concentrated juice is added in an amount of 75-85% of the fermentation tank capacity, and the natural fermentation is carried out at a fermentation temperature of 19-21°C, and the residual sugar content is detected every 24 hours; 6) Terminate the fermentation, when the residual sugar content drops to 9-11°Bx, invert the tank, remove the sludge, separate the supernatant, add the terminator and cool the wine temperature, monitor the changes of the wine and residual sugar every 8 hours, until the residual sugar remains basically unchanged; 7) Clarification and filtration, aging at 2°C for 2 weeks, inverting the tank 1-2 times during this period, and obtaining red grape moussale after membrane filtration; 8) Sterilization and finished product, the red grape moussale is sterilized to obtain a finished wine.

[0025] Advantages of the present invention:

[0026] The preparation method of the present invention can significantly increase the content of phenolic substances and the antioxidant activity of red grape moussalais, and greatly improve the economic value of the finished wine;

[0027] The wine brewed by the method of the invention has bright color, presents brick red, has a full and coordinated wine body, a mellow taste, has a distinct typicality, and can effectively improve the quality and antioxidant capacity of moussalais. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a comparison chart of the phenolic content of red grape moussae in different fermentation types in the experiment of the present invention;

[0029] Figure 2 The antioxidant capacity of different fermented types of red grape moussae in the experiment of the present invention;

[0030] Figure 3 This is a correlation analysis diagram of phenol, color parameters and antioxidant capacity in the experiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0032] Example:

[0033] A fermentation brewing method for improving the quality of red grape moussalais comprises the following steps:

[0034] 1) Prepare to wash and select red grapes that are fresh, mature, free of rot, deterioration, disease and insect pests;

[0035] 2) Juice extraction, precipitation and skin-dregs separation: the grapes are washed and fully squeezed and crushed, and the skin-dregs are separated by precipitation. The separated grape juice is immersed in low temperature for 24 hours, and the low temperature range is 10-15°C;

[0036] 3) heating and concentrating, mixing the separated skin residue with water and boiling until the sugar content of the juice reaches 11-13°Bx, filtering to remove residue, mixing the filtrate with the grape juice soaked in step 2) and boiling, detecting the sugar content during boiling, and when the sugar content reaches 25°Bx, the concentration is completed, cooling is performed to obtain concentrated juice;

[0037] 4) Ingredient adjustment: the total acid of the concentrated juice is adjusted to pH 3.7;

[0038] 5) Natural fermentation: the adjusted concentrated juice is sent to the fermentation tank, the amount of concentrated juice added is 80% of the capacity of the fermentation tank, and the natural fermentation is carried out at a fermentation temperature of 19-21°C, and the residual sugar content is tested every 24 hours;

[0039] 6) Terminate the fermentation. When the residual sugar content drops to 9-11°Bx, turn the cans over, remove the sludge, separate the supernatant, add the terminator and cool the wine to -10°C. Monitor the changes in the wine and residual sugar every 8 hours until the residual sugar remains basically unchanged.

[0040] 7) clarifying and filtering, aging at 2°C for 2 weeks, during which time the cans are decanted 1-2 times, and filtering through a membrane to obtain red grape moussale;

[0041] 8) sterilizing and finishing the wine, sterilizing the red grape moussalis to obtain a finished wine.

[0042] In the step 3), the skin residue is mixed with water in a mass ratio of 1:1.5; and the step of filtering and removing the residue is performed by filtering with gauze to remove the residue.

[0043] In the step 4), the total acid is adjusted by tartaric acid.

[0044] In the step 6), the terminator is 120 mg / L potassium metabisulfite.

[0045] The membrane in step 7) is a 0.45 um membrane.

[0046] Effects of different skin residue treatments on the quality and antioxidant capacity of red grape moussala

[0047] In this experiment, red grapes were used as raw materials. Different treatments were performed on the red grape skin and residue. The fermentation process of Moussalaise was used to brew the skin and water concentration fermentation, juice concentration fermentation, whole fruit wine fermentation, and skin fermentation Moussalaise. The physicochemical indexes, color changes, phenolic content and antioxidant activity of red grape Moussalaise treated with four different skin and residue treatments were compared, and the raw material treatment method with the highest comprehensive score was selected by principal component analysis.

[0048] 1 Materials and methods

[0049] 1.1 Materials and reagents

[0050] Red grapes: purchased from Jiuding Market in Urumqi, Xinjiang; Folin phenol (analytical grade): Beijing Solebow Technology Co., Ltd.; Potassium metabisulfite: Tianjin Fuchen Chemical Reagent Factory; Anhydrous sodium carbonate (analytical grade): Tianjin Zhiyuan Chemical Reagent Co., Ltd.; Gallic acid standard (purity > 98%): Shanghai Yuanye Biotechnology Co., Ltd.

[0051] 1.2 Instruments and Equipment

[0052] Red grapes: purchased from Jiuding Market in Urumqi, Xinjiang; Folin phenol (analytical grade): Beijing Solebow Technology Co., Ltd.; Potassium metabisulfite: Tianjin Fuchen Chemical Reagent Factory; Anhydrous sodium carbonate (analytical grade): Tianjin Zhiyuan Chemical Reagent Co., Ltd.; Gallic acid standard (purity > 98%): Shanghai Yuanye Biotechnology Co., Ltd.

[0053] 1.3 Methods

[0054] 1.3.1 Brewing process

[0055] Fresh grapes → washing and selecting → juicing → sedimentation → skin and residue separation → heating and concentration → cooling and filtration → ingredient adjustment → natural fermentation → termination of fermentation → clarification and filtration → sterilization → finished wine

[0056] Specific operations:

[0057] 1) Wash and select red grapes that are fresh, mature, free of rot, deterioration, disease and insect pests;

[0058] 2) Juice extraction, precipitation and skin-dregs separation: the grapes are washed and fully squeezed and crushed, and the skin-dregs are separated by precipitation. The separated grape juice is immersed in low temperature for 24 hours, and the low temperature range is 10-15°C;

[0059] 3) heating and concentrating, mixing the skin residue and water in a mass ratio of 1.0:1.5 (g:g) and boiling, heating and boiling the juice with an induction cooker to a sugar content of (12±1)°Bx, filtering with gauze to remove the skin residue after cooling, mixing the filtrate with the above grape juice and boiling, regularly checking the sugar content during the boiling process, and completing the concentration when the sugar content is 25°Bx, and cooling to obtain a concentrated juice;

[0060] 4) Ingredient adjustment: the total acid of the concentrated juice is adjusted to pH 3.7 with tartaric acid;

[0061] 5) Natural fermentation: the adjusted concentrated juice is sent to the fermentation tank, the amount of concentrated juice added is 80% of the capacity of the fermentation tank, and the natural fermentation is carried out at a fermentation temperature of 19-21°C, and the residual sugar content is tested every 24 hours;

[0062] 6) Terminate the fermentation. When the residual sugar content drops to 9-11°Bx, invert the tank, remove the sludge, separate the supernatant, add 120 mg / L potassium metabisulfite, and terminate the fermentation by freezing.

[0063] 7) Clarification and filtration, aging at 2°C for 2 weeks, during which time the cans are poured 1-2 times, and red grape moussale is obtained after filtration through a 0.45 um membrane.

[0064] 1.3.2 Brewing of red grape moussalais with different fermentation types

[0065] Concentrated fermentation of peel residue with water: follow the above specific operation, except that the peel residue is diluted with water at a mass ratio of 1.0:1.5 (g:g), the sugar content is concentrated to 25°Bx, the pH is adjusted to 3.7 after cooling, and fermented at a constant temperature of (20±1)°C. When the residual sugar content of the fermentation liquid reaches (10±1)°Bx, pure peel residue concentrated fermented red grape moussale is obtained by filtering.

[0066] Original juice concentrated fermentation: follow the above-mentioned specific operation, except that the original juice (i.e. the grape juice obtained by squeezing and separation) is concentrated to a sugar content of 25°Bx, the pH is adjusted to 3.7 after cooling, and the fermentation is carried out at a constant temperature of (20±1)°C. When the residual sugar content of the fermentation liquid reaches (10±1)°Bx, it is filtered to obtain the pure juice concentrated fermented red grape Moussalais.

[0067] The skin residue is mixed with water and the original juice is fermented: after the above-mentioned specific operations, red grape moussalaise is obtained.

[0068] Juice concentration and fermentation with skin: The above specific operation is followed, except that the grape juice (grape juice obtained by pressing and separation) is concentrated to 25°Bx in sugar content, and after cooling, red grape skin residue is added in the proportion of 10%, 30%, and 50% of the concentrated juice, and the pH is adjusted to 3.7. Fermentation is carried out at a constant temperature of (20±1)℃. When the residual sugar content of the fermentation liquid reaches (10±1)°Bx, the fermented red grape moussalis with skin is obtained by filtration. (The skin residue of fermentation with skin is not concentrated, and grape skin residue is added in proportion after the juice is concentrated.)

[0069] For the sake of ease of presentation, the four different types of Moussalais are respectively called peel and water fermentation (peel and water concentrated fermentation), skin fermentation (original juice concentrated skin fermentation), whole juice fermentation (original juice concentrated fermentation), whole fruit wine fermentation (skin and residue mixed with water and original juice fermentation). The skin and residue of skin fermentation are not concentrated, and after the juice is concentrated, grape skin and residue are added at a ratio of 10%, 30%, and 50% respectively.

[0070] 1.3.3 Determination of physical and chemical indicators

[0071] Determination of alcohol content: refer to GB5009.225-2016 "National Food Safety Standard Determination of Ethanol Concentration in Wine"; Determination of volatile acid and total acid: determine in accordance with GB / T15038-2006 "General Analysis Method for Grape and Fruit Wine".

[0072] 1.3.4 Determination of chromaticity index

[0073] Aim the measuring head of the colorimeter at the standard white plate or calibration plate for black and white calibration. Place the wine sample under the measuring window of the colorimeter to ensure that the wine sample fills the entire measuring area. Start the colorimeter for measurement and record the values ​​of L* (brightness), a* (red-green intensity), and b* (yellow-blue intensity). Repeat the measurement three times for each sample and take the average value of L*, a*, and b* as the color characteristic of the wine sample.

[0074] 1.3.5 Determination of phenolic content

[0075] Determination of total phenol content: Folin phenol reagent colorimetry was used. The absorbance of the sample was measured at a wavelength of 760 nm, and a gallic acid standard curve was drawn with gallic acid as the standard, gallic acid content (x) as the horizontal coordinate, and absorbance value (y) as the vertical coordinate. The regression equation of the gallic acid standard curve was y=0.1649x+0.1163, and the correlation coefficient R2=0.9953.

[0076] Determination of total flavonoids content: The NaNO2-Al(NO3)3 method was used (Ye Songhua, Wang Xiaoyan, Yang Yingying, et al. Study on the extraction process of total flavonoids from Rosa spicata fruit [J]. Journal of Shanxi Medical University, 2013, 44(7): 535-538). The absorbance value of the sample was measured at a wavelength of 510 nm. Rutin was used as the standard, rutin content (x) as the horizontal coordinate, and absorbance value (y) as the vertical coordinate to draw a rutin standard curve. The regression equation of the rutin standard curve was y=0.3127x+0.0028, and the correlation coefficient R2=0.9989.

[0077] 1.3.6 Antioxidant capacity determination

[0078] Determination of DPPH free radical scavenging rate: refer to the method of Guo Changqing et al. (

[13] Guo Changqing, Xia Shiqi, Shao Qifei, et al. Determination of total flavonoids content and antioxidant effect of different parts of rosewood [J]. Southern Forestry Science, 2023, 51(3): 11-5.) and make slight modifications. Mix 1 mL of the test solution with 1 mL of 0.2 mmol / LDPPH solution, let stand for 30 min, adjust to zero with anhydrous ethanol, and measure the absorbance at a wavelength of 517 nm. The sample absorbance is A1. Mix 1 mL of the test solution with 3 mL of anhydrous ethanol and let stand for 30 min. Under the same conditions, the sample blank absorbance is A2. Mix 1 mL of anhydrous ethanol distilled water with 3 mL of 0.2 mg / mL DPPH solution and let stand for 30 min. Under the same conditions, the control group absorbance is A0.

[0079] HASR hydroxyl radical determination: refer to the method of Wu Hong et al. (Wu Hong, Huang Qiong, Li Dengming. Functional components and antioxidant activity of blueberry products at different fermentation stages [J]. Chinese Condiments, 2023, 48(9): 94-103.) with slight modifications. Take a 10mL test tube and add 1mL 9mmol / L salicylic acid solution, 1mL alcohol sample, 1mL 8.8mmol / L hydrogen peroxide solution and 1mL 9mmol / L ferrous sulfate solution; add 1mL 9mmol / L salicylic acid solution, 1mL alcohol sample, 1mL 8.8mmol / L hydrogen peroxide solution; add 1mL 9mmol / L salicylic acid solution, 1mL alcohol sample, 1mL 8.8mmol / L hydrogen peroxide solution and 1mL 9mmol / L ferrous sulfate solution; add 1mL 9mmol / L salicylic acid solution, 1mL alcohol sample, 1mL 8.8mmol / L hydrogen peroxide solution in a 10mL test tube as a blank group; after mixing, take the supernatant and measure its absorbance at 510nm.

[0080] F3 +Reducing ability: Take 1 mL of the wine sample to be tested, add 2.5 ml of pH 6.6 phosphate buffer and 2.5 ml of 1% potassium ferricyanide solution, mix in a 50°C water bath for 20 min, then add 2.5 ml of 10% trichloroacetic acid solution to terminate the reaction. After mixing the reaction solution, centrifuge at 3000 rpm for 10 min, accurately aspirate 5 ml of the supernatant, add 5 ml of distilled water and 0.5 ml of 0.1% ferric chloride solution, mix thoroughly, and measure the absorbance of the reaction solution at 700 nm (Li Yong. Research on the determination method of antioxidant activity of wine [D]. Yangling: Northwest Agriculture and Forestry University, 2011.).

[0081] 1.3.7 Fuzzy Mathematics Sensory Evaluation of Different Fermentation Types of Red Grape Moussala

[0082] Referring to the method of Zhang Xun et al. (Zhang Xun, Zhang Lixia, Luxin, et al. Combining mixing test with fuzzy evaluation to optimize the process of extruded puffed sesame products [J]. Food Science, 2018, 39(4): 248-253.), the factors are represented by set U, then U = {u1, u2, u3, u4} = {color, aroma, taste, style}, and the comments are represented by set V, V = {v1, v2, v3, v4} = {excellent, good, medium, poor}, the test The four levels of medium, excellent, good and medium-poor correspond to 90, 80, 70 and 60 points respectively, the evaluation V = {v1, v2, v3, v4} = {90, 80, 70, 60}, the weight set Y = {y1, y2, y3, y4} = {0.15, 0.30, 0.30, 0.25} and the matrix multiplication is used according to the fuzzy mathematics change principle to obtain the comprehensive membership Ri of the wine sample to the four factors.

[0083] The evaluation panel consisted of 10 people with fruit wine tasting qualifications. They scored the three wine samples based on four evaluation indicators: color, aroma, taste, and typicality. The scoring levels were excellent, good, medium, and poor. The evaluation criteria are shown in Table 1.

[0084] Table 1 Sensory evaluation standards of redgrape Musalais

[0085]

[0086] 1.3.8 Data processing and analysis

[0087] Excel 2019 was used to process the data; SPSS29.0 software was used for statistical analysis; and Origin 2021 was used for drawing.

[0088] 2 Results and analysis

[0089] 2.1 Analysis of physical and chemical indicators of red grape moussalais from different fermentation types

[0090] The results of basic physical and chemical indicators of the 6 wine samples are shown in the table. The reducing sugar content is 12.60-14.70 g / L, the alcohol content is 10.52-11.08% vol, the total acid content is 7.27-8.60 g / L, and the pH value is 3.39-3.52. This may be because fermentation with skins is conducive to the fermentation process. The fermentation liquid fermented with grape skins added after grape juice concentration ferments faster than other fermentation groups.

[0091] Table 2 Analysis of physicochemical indexes of red grape moussalais in different fermentation types

[0092] Table 2 Analysis of Physical and chemical Indicators in different fermentation varieties of red grape Musalais

[0093]

[0094] 2.2 Color parameters of red grape moussalais of different fermentation types

[0095] The L* value is inversely proportional to the color depth of the fruit wine. The lower the L* value, the darker the color of the wine sample. The higher the a* value, the greater the red component in the wine color. The higher the b* value, the greater the yellow component in the wine color.

[0096] As shown in Table 2, the range of color parameters in different fermentation types of red grape moussalais is L* value: 28.82-31.60, a* value: 1.09-3.59, b* value: -0.02-0.91, ΔE: 29.05-31.62.

[0097] The order of color changes is L* value and ΔE: fermentation with skin > whole juice fermentation > whole fruit wine fermentation > fermentation with skin and water, among which, whole juice fermentation > fermentation with 50% skin > fermentation with 30% skin > fermentation with 10% skin;

[0098] a* value: fermentation with peel and water > fermentation with whole fruit wine > fermentation with peel > fermentation with original juice, among which original juice fermentation > fermentation with 50% peel. The a* values ​​of the six different fermentation matrices are all greater than 0, tending to be red;

[0099] b* value: Except for the b* values ​​of original juice fermentation and 50% fermentation with skins which are <0, the b* values ​​of the other four types of red grape Moussalais are >0 and tend to be yellowish. The reason for this phenomenon may be that after the skin residue and juice are concentrated, the carbonyl-amine reaction between reducing sugars reduces the amino acid content, causing adverse changes in color, resulting in darker wine color, a red hue, and increased yellowing.

[0100] Table 3 Color parameters in different fermentation varieties of red grape Musalais

[0101]

[0102] 2.3 Comparison of phenolic content in red grape mousseline from different fermentation types

[0103] Total phenols and flavonoids are one of the important functional ingredients in fruit wine. They not only play a role in the antioxidant properties of fruit wine, but also play an important role in the color and smell of fruit wine. Under the same initial conditions, the total phenols and flavonoids contents of different fermented types of red grape mussels are different after fermentation.

[0104] Effects of different raw material processing methods on antioxidant substances in red grape moussalais Figure 1 The order of total phenol content is peel and water fermentation > whole fruit wine fermentation > whole juice fermentation > fermentation with peel; the order of total flavonoid content is peel and water fermentation > whole fruit wine fermentation > fermentation with skin > whole juice fermentation.

[0105] Fermentation with residue can better extract the nutrients in the peel and pulp, and increase the content of phenolic compounds in the wine. During the fermentation of red grape moussalaise, with the increase of the amount of peel residue (without concentration treatment), the content of phenolic substances decreased. It may be that the large amount of peel residue has a certain inhibitory effect on the activity of yeast, which is not conducive to the fermentation. In contrast, the concentrated red grape peel residue can better promote the extraction of phenolic substances in the peel, thereby increasing the content of phenolic substances in the fruit wine.

[0106] 2.4 Analysis of antioxidant activity of red grape moussae from different fermentation types

[0107] The antioxidant activity of wine is affected by many factors, which is mainly closely related to the types and total content of phenolic substances widely present in wine. Figure 2As shown in the figure, the hydroxyl radical scavenging rate, DPPH radical scavenging rate and iron reducing capacity of the peel and water fermentation were higher than those of other treatment groups, followed by whole fruit wine fermentation, and the hydroxyl radical scavenging rate and iron reducing capacity of whole juice fermentation were the lowest. The DPPH radical scavenging rate and iron reducing capacity of 50% fermentation with skin were lower than those of other treatment groups, indicating that the antioxidant capacity of red grape Moussalais fermented with skin was generally lower than that of whole juice fermentation and whole fruit fermentation. It may be due to the massive growth and reproduction of yeast and the metabolic transformation of substances during natural fermentation with skin, which caused the loss of antioxidant components and led to the decrease of antioxidant performance of fermentation liquid. The concentrated peel contains more phenolic and flavonoid substances, which will be continuously precipitated during the fermentation process and dissolved in the fruit wine, thereby improving the antioxidant capacity. It shows that compared with other types of wine, the wine fermented with peel and water has better antioxidant properties.

[0108] 2.5 Sensory characteristics of red grape moussalais of different fermentation types

[0109] 2.5.1 Fuzzy Mathematics Sensory Evaluation Results

[0110] The fuzzy mathematical sensory results of the six wine samples are shown in Table 4. Excellent, good, fair, and poor were assigned scores of 90, 80, 70, and 60 points respectively.

[0111] Table 4 Fuzzy mathematical sensory results of different fermentation types of red grape moussala

[0112] Table 4Fuzzy mathematical densory results in different types of offered red

[0113] grape Musalais

[0114]

[0115]

[0116] Through the analysis of wine sample No. 1 in Table 3, an evaluation matrix of four single factors, namely color, aroma, taste and style, was established: U1 appearance = (0.50 0.30 0.20 0.00); U1 aroma = (0.70 0.20 0.10 0.00); U1 taste = (0.200.40 0.300.10); U1 typicality = (0.30 0.20 0.40 0.10).

[0117] 2.5.2 Comprehensive sensory evaluation based on fuzzy mathematics

[0118] According to the tasting scores, the sensory comprehensive evaluation results and fuzzy mathematical evaluation matrix were obtained. Taking the No. 1 (U1) wine sample as an example, the comprehensive membership R1 is as follows:

[0119]

[0120] The fuzzy evaluation results of the wine samples were calculated, and the final sensory scores of each sample were obtained after addition. For example, the final sensory score of wine sample No. 1 (U1) was Y1=0.420×90+0.275×80+0.250×70+0.055×60=81.65; similarly, the final sensory scores of wine samples Y2 to Y6 were: Y2=82.55, Y3=81.5, Y4=79.56, Y5=75.5, Y6=85.6, and the order of comprehensive evaluation scores was: Y6>Y2>Y1>Y3>Y4>Y5

[0121] The whole fruit wine fermentation product of Musalais is more popular than the fermentation of peel and water, original juice, and fermentation with skin. The wine is bright red, clear and transparent, with good color, mellow body, and relatively rich taste; the fermentation of peel and water, the wine is dark in color, sour and astringent in taste, and the fruit aroma covers the wine aroma, indicating that the fermentation of peel and water can increase the fruit aroma of red grape Musalais; the original juice fermentation wine is clear and bright, but the fruit aroma is insufficient, and the mellow aroma covers the fruit aroma; with the increase of the amount of skin residue added, the color of the fermented wine is lighter, the wine is lighter, and the aroma is insufficient. This shows that the wine obtained by boiling the skin residue with water and mixing it with grape juice for fermentation has a better fusion of fruit aroma and mellow aroma.

[0122] 2.6 Principal component analysis of red grape moussalas from different fermentation types

[0123] In order to analyze the internal relationship between the color index, phenolic substances and antioxidant capacity of red grape Moussalais, the correlation analysis of the color index, phenolic substance content and antioxidant capacity of wine was carried out. The relationship between the color, phenolic substance content and antioxidant capacity of red grape Moussalais in different fermentation types (skin and water fermentation, whole juice fermentation, whole fruit wine fermentation, skin fermentation) was analyzed respectively. The correlation coefficients are shown in Table 1. Figure 3 There was a very significant positive correlation between total phenol content and flavonoids content, DPPH free radical scavenging rate, hydroxyl free radical scavenging ability and iron reducing ability, and b* value, and between flavonoids and hydroxyl free radical scavenging rate (P<0.01); there was a significant positive correlation between total phenol content and hydroxyl free radicals and a* value (p<0.05); there was a very significant negative correlation between L* value and ΔE and total phenol, DPPH free radical scavenging rate, iron reducing ability, and b* value (P<0.01); there was a significant negative correlation between L* value and ΔE and total flavonoids, hydroxyl free radical scavenging rate and a* value (p<0.05).

[0124] After concentration, the brightness of the grape juice will decrease, the yellowing will intensify, and the overall color will appear reddish brown. During the concentrated fermentation process of the juice, the pigment may be concentrated, oxidized, and the color may change.

[0125] In order to intuitively analyze the effects of different skin residue treatments on red grape moussalais, the nine indicators of six different fermented types of moussalais were subjected to principal component analysis, and the results are shown in Table 5. The eigenvalues ​​of the first two principal components were 5.554 and 3.222, respectively, of which PC1 (the first principal component) was 61.7% and PC2 (the second principal component) was 32.8%, and the cumulative variance contribution rate reached 97.5%.

[0126] Table 5 Eigenvalues ​​and contribution rates of principal components

[0127]

[0128] Table 6 Load matrices of principal components

[0129]

[0130] The color change, phenolic content, and antioxidant capacity of red grape moussals from different fermentation types were comprehensively analyzed. The scores of each principal component and the comprehensive score are shown in Table 7. The top three comprehensive rankings are fermentation with skin residue and water (0.946), whole fruit wine fermentation (0.574), and fermentation with 10% skin (0.258). The difference in ranking between fermentation with skin and whole juice fermentation may be that some antioxidants in the red grape skin residue were not detected by the total antioxidant capacity, which improved the overall effect. This further illustrates that the principal component analysis of red grape moussals from different fermentation types can be comprehensively analyzed to screen out the best fermentation matrix.

[0131] Table 7 Main component score and comprehensive score of red grape musalais cider

[0132]

[0133]

[0134] 3. Conclusion

[0135] The study on the effects of different methods on the treatment of red grape skin residue showed that these treatments can significantly affect the content of phenolic substances and its antioxidant activity in red grape Moussalais. The Moussalais wine brewed from concentrated peels has a higher content of total phenols and flavonoids. There was no significant difference in the DPPH free radical scavenging ability among the data of each group, but the hydroxyl free radical scavenging ability (HRSA) and iron ion reducing power showed certain differences, especially the Moussalais fermented with concentrated peels and water (no grape juice was added, and the skin residue was directly fermented after concentration with water), the phenolic content and antioxidant capacity were better than those of other treatments; for the fermentation group with skin, with the increase of the amount of skin residue added, the phenolic content and antioxidant capacity showed a downward trend, and the Moussalais fermented with whole fruit performed best in sensory scores. Based on the results of comprehensive color, sensory evaluation and principal component analysis, the whole-fruit fermented Moussalais performed the best overall. The wine obtained by this brewing method is bright in color, brick red, full-bodied and harmonious, with a mellow taste and distinctive typicality, which can effectively improve the quality and antioxidant capacity of Moussalais.

[0136] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A fermentation brewing method for improving the quality of red grape moussalais, characterized in that: The following steps are involved: 1) Prepare to wash and select red grapes that are fresh, mature, free of rot, deterioration, disease and insect pests; 2) Juice extraction, precipitation and skin-dregs separation: the grapes are washed and fully squeezed and crushed, and the skin-dregs are separated by precipitation. The separated grape juice is immersed in low temperature for 20 to 30 hours, and the low temperature range is 10 to 15°C; 3) heating and concentrating, mixing the separated skin residue with water and boiling until the sugar content of the juice reaches 11-13°Bx, filtering to remove residue, mixing the filtrate with the grape juice soaked in step 2) and boiling, detecting the sugar content during boiling, and when the sugar content reaches 25°Bx, the concentration is completed, cooling is performed to obtain concentrated juice; 4) Ingredient adjustment: the total acid of the concentrated juice is adjusted to pH 3.7; 5) Natural fermentation: the adjusted concentrated juice is sent to the fermentation tank, the amount of concentrated juice added is 75-85% of the capacity of the fermentation tank, and the natural fermentation is carried out at a fermentation temperature of 19-21°C, and the residual sugar content is tested every 24 hours; 6) Terminate the fermentation. When the residual sugar content drops to 9-11°Bx, turn the can over, remove the sludge, separate the supernatant, add the terminator and cool the wine down. Monitor the changes in the wine and residual sugar every 8 hours until the residual sugar remains basically unchanged. 7) clarifying and filtering, aging at 2°C for 2 weeks, during which time the cans are decanted 1-2 times, and filtering through a membrane to obtain red grape moussale; 8) sterilizing and finishing the wine, sterilizing the red grape moussalis to obtain a finished wine.

2. A fermentation brewing method for improving the quality of red grape moussalais according to claim 1, characterized in that: In the step 2), the mixture is immersed in water at low temperature for 24 hours.

3. A fermentation brewing method for improving the quality of red grape moussale according to claim 1, characterized in that: In the step 3), the skin residue is mixed with water in a mass ratio of 1:1.5; and the step of filtering and removing the residue is performed by filtering with gauze to remove the residue.

4. A fermentation brewing method for improving the quality of red grape moussalais according to claim 1, characterized in that: In the step 4), the total acid is adjusted by tartaric acid.

5. A fermentation brewing method for improving the quality of red grape moussale according to claim 1, characterized in that: In step 5), the amount of concentrated juice added is 80% of the capacity of the fermentation tank.

6. A fermentation brewing method for improving the quality of red grape moussale according to claim 1, characterized in that: In the step 6), the terminator is 120 mg / L potassium metabisulfite.

7. A fermentation brewing method for improving the quality of red grape moussale according to claim 1, characterized in that: The membrane in step 7) is a 0.45 um membrane.

8. A fermentation brewing method for improving the quality of red grape moussale according to claim 1, characterized in that: In the step 6), the temperature is lowered to -10°C.

Images