Blueberry wine added with pitaya wine residues for auxiliary fermentation and brewing method of blueberry wine

Abstract

The invention relates to the technical field of blueberry wine brewing, in particular to blueberry wine added with pitaya wine residues for auxiliary fermentation and a brewing method of the blueberry wine. The brewing method comprises the following steps: S1, pretreating pitaya wine residues; step S2, fermenting the blueberry wine; and step S3, sterilizing and canning. According to the brewing method disclosed by the invention, pitaya wine residues subjected to ultrasonic treatment are selected as an auxiliary substrate and are subjected to compound fermentation with sliced blueberry fruits, so that the content of antioxidant active substances such as anthocyanin and total polyphenol in the finished blueberry wine is increased, and volatile aroma components in the finished blueberry wine are also increased; in addition, the compound clarifying agent is adopted, so that a good clarifying effect on a compound fermentation system is achieved, and the taste of the finished blueberry wine is enriched.

Description

Technical Field

[0001] The invention relates to the technical field of blueberry wine brewing, in particular to blueberry wine with pitaya residue added to assist in fermentation and a brewing method thereof. Background Art

[0002] The wine industry is booming. If the wine residues produced by a large amount of brewing are discarded at will, it will not only occupy precious land resources, but also breed bacteria and mosquitoes due to natural fermentation and decay, causing pollution to the surrounding ecological environment and increasing the cost of environmental protection. From the perspective of economic value, wine residues are by no means worthless waste. They are rich in nutrients and active substances such as anthocyanins, dietary fiber, and polyphenols. After extraction and processing, these ingredients can be used again in the fields of food, cosmetics, and health products to make jams, facial masks, dietary supplements and other products, opening up new profit channels for enterprises and reducing raw material costs. In addition, the society's call for natural, green, and healthy products is growing. The rational use of wine residues to develop derivative products just meets market demand, improves consumers' overall satisfaction with the industrial chain, and promotes a virtuous cycle of the industry. It can be seen that its effective use is imperative.

[0003] In the traditional brewing process, from the screening and crushing of fruit raw materials to a series of processes such as fermentation and aging, many factors cause a large loss of some antioxidant-reducing substances. Taking common fruit wine as an example, the storage time after the fruit is picked, the temperature control during the processing, and the role of microorganisms will cause the antioxidant-reducing substances such as anthocyanins and flavonoids, which were originally not high in content, to gradually lose, and when the brewing is completed, there will be very little left. However, these substances are of great significance to human health. They can effectively remove free radicals, delay aging, and prevent chronic diseases. In view of this, in order to meet the growing health demands of consumers and ensure the nutritional and health functions of fruit wine, on the basis of following food safety regulations and brewing scientific principles, by adding antioxidant-reducing substances from natural sources and strictly tested, it has become a necessary way to promote the upgrading of the fruit wine industry and create high-quality fruit wine products. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to overcome the deficiencies in the prior art and provide a blueberry wine with pitaya dregs added for auxiliary fermentation and a brewing method thereof. The brewing method uses fresh blueberries and pitaya dregs as raw materials, adds composite yeast for fermentation, uses a composite clarifier to clarify the wine, and then determines physical and chemical indicators, etc., so as to reasonably utilize resources. The obtained blueberry wine has rich taste, high content of antioxidant active substances and sufficient aroma.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A method for brewing blueberry wine by adding pitaya wine residue to assist fermentation, specifically comprising the following steps:

[0007] Step S1, pretreatment of pitaya wine residue, quickly washing the blueberry wine residue after preliminary filtration with distilled water to remove sugar, alcohol and impurities attached to the surface to prevent microbial growth; then spreading it on a clean gauze, draining the water naturally, turning it over in time during the process to ensure uniform drying, and controlling the drying time within 30 minutes to prevent the oxidation loss of effective ingredients; using a small grinder to grind the drained blueberry wine residue into powder, passing it through a 60-mesh sieve to make the wine residue particles uniform in size, intermittently grinding to control the temperature to prevent the denaturation of antioxidants due to frictional heat, placing it in an ultrasonic device, ultrasonicating it at room temperature for 55 minutes, and setting it aside;

[0008] Step S2, blueberry wine fermentation;

[0009] Step S3, sterilization and canning, the filtered blueberry wine is instantaneously sterilized and analyzed and then canned to obtain blueberry wine;

[0010] Wherein, the step S2 specifically includes the following steps:

[0011] Step S21, washing: selecting unbroken fresh blueberries, washing them with potassium metabisulfite solution, and picking out floating shrunken fruits and small fruits;

[0012] Step S22: crushing: a slicer cuts and crushes the blueberry fruit into slices;

[0013] Step S23, adjusting the ingredients, putting the crushed blueberry pulp into a sterilized stainless steel fermentation tank, adding yellow crystal sugar, honey, pectinase, compound yeast, yeast nutrient, adjusting the acidity, and mixing evenly to obtain a mixed system;

[0014] Step S24, temperature-controlled main fermentation: placing the mixed system obtained in step S23 at a low temperature of 14-16° C., and when the alcohol content reaches 6% vol, adding dragon fruit wine residue into the fermentation tank, mixing well, and continuing fermentation under the same conditions;

[0015] Step S25, monitoring the fermentation process, monitoring the fermentation progress by measuring specific gravity, sugar content, acidity and alcohol content, and determining whether the main fermentation has stopped;

[0016] Step S26, post-fermentation temperature control, after the main fermentation stops, the mixed system obtained in step S25 is placed in an environment of 18-22° C. for post-fermentation, so that the pitaya wine residues continue to extract redox substances and flavor components in the ethanol solution produced by the blueberry wine, the post-fermentation time lasts for 3 months, and the canning time is determined by continuous monitoring and regular tasting to obtain the first-grade blueberry wine;

[0017] Step S27, aging, pouring the blueberry wine obtained in step S26 into a new fermentation tank, aging for 6 months at 10-15° C. and 70% air humidity, removing the wine lees, and obtaining a blueberry wine intermediate;

[0018] Step S28, clarification and filtration: adding a composite clarifier to the blueberry wine intermediate obtained in step S27, leaving it for 10 days, clarifying the wine by natural sedimentation, and filtering to obtain clarified blueberry wine;

[0019] Step S3, sterilization and canning, the filtered clarified blueberry wine is instantaneously sterilized and analyzed and then canned to obtain a finished blueberry wine.

[0020] Furthermore, in step S21, the mass percentage of potassium pyrosulfite in the potassium pyrosulfite solution is 0.05-0.08%.

[0021] Furthermore, in step S22, the thickness of the blueberry fruit slices is 0.5 cm.

[0022] Furthermore, in step S23, the mass ratio of blueberry pulp, yellow crystal sugar, honey, pectinase, compound yeast, and yeast nutrient is 1000:150:100:10:10:3; the acidity is adjusted specifically by adding citric acid or tartaric acid to adjust the pH value of the mixed system to 3.3-3.8.

[0023] Furthermore, in step S23, the pectinase is one of pectinesterase, protopectinase, polygalacturonase and pectin lyase.

[0024] Furthermore, in step S24, the volume ratio of blueberry pulp to pitaya dregs is 1:(10-20).

[0025] Furthermore, in step S24, the composite yeast includes brewer's yeast, non-brewer's yeast RM12, and DE yeast, and the mass ratio of brewer's yeast, non-brewer's yeast RM12, and DE yeast is 1:(0.25-1):(0.25-1).

[0026] Furthermore, in step S25, the specific operation of monitoring the fermentation process is: stirring the fermentation barrel once every two days, when the specific gravity drops to 1.100, the sugar content drops below 170g / L, and a large number of bubbles are generated and gradually decrease, it indicates that the main fermentation gradually stops.

[0027] Furthermore, in step S28, the composite clarifier includes pectinase and gelatin, and the mass ratio of pectinase to gelatin is 1:(2-5).

[0028] The invention discloses a blueberry wine with pitaya dregs added to assist fermentation, which is prepared by adopting the brewing method.

[0029] The beneficial effects of the present invention are as follows: the brewing method of the present invention is simple and has the following advantages:

[0030] (1) In the brewing method of the present invention, the dragon fruit wine residue after ultrasonic treatment is selected as the auxiliary substrate, and the blueberry slices are fermented together, which not only increases the content of anthocyanins, total polyphenols and other antioxidant active substances in the finished blueberry wine, but also increases the volatile aroma components in the finished blueberry wine; in addition, the composite clarifier is used, which has a good clarification effect on the composite fermentation system and enriches the taste of the finished blueberry wine;

[0031] (2) In the brewing method of the present invention, pitaya wine residue is used as a co-substrate to carry out composite fermentation with sliced ​​blueberry fruit, so as to recycle the wine residue resources, further explore the antioxidant active substances rich in the wine residue waste, and improve the resource utilization rate;

[0032] (3) In the brewing method of the present invention, the taste and flavor of blueberry wine can be retained to the greatest extent through continuous low-temperature fermentation, and there is no blending in the brewing process, which retains the original aroma components of blueberries during fermentation and enriches the types of flavor substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 This is a comparison chart of the antioxidant reducing substance content of the blueberry wine (T) with added pitaya dregs prepared in Example 1 and the original blueberry wine (CK) prepared in Comparative Example 1. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] 1. Materials and equipment

[0040] 1.1 Materials and reagents

[0041] Blueberry wine: homemade in the laboratory; Folin phenol standard, gallic acid, Shanghai McLean Biochemical Technology Co., Ltd.; phenol, Shanghai Lingfeng Chemical Reagent Co., Ltd.; malic acid, citric acid, lactic acid, acetic acid, Shanghai Aladdin Biochemical Technology Co., Ltd.; diphenylpicrylhydrazyl (DPPH), Sigma, USA; plate count agar medium, Bengal red medium, Beijing Luqiao Technology Co., Ltd.

[0042] 1.2 Instruments and Equipment

[0043] Leici PHS-3E pH meter, Shanghai Yidian Company; PAL-1 handheld sugar meter, Japan ATAGO Company; Neofugel5R magnetic stirrer, Shanghai Lixin Company; ML204T analytical balance, Shanghai Mettler Company; R201C constant temperature water bath, Gongyi Yuhua Company; UV2600 ultraviolet spectrophotometer, Japan Shimadzu Corporation; VD-650 sterile operating table, Suzhou Purification Equipment Co., Ltd.; HB600-S electric constant temperature incubator, Shanghai Yuejin Medical Equipment Factory.

[0044] 2. A method for brewing blueberry wine by adding pitaya dregs to assist fermentation, specifically comprising:

[0045] Step S1, pretreatment of pitaya wine residue, quickly washing the blueberry wine residue after preliminary filtration with distilled water to remove sugar, alcohol and impurities attached to the surface to prevent microbial growth; then spreading it on a clean gauze, draining the water naturally, turning it over in time during the process to ensure uniform drying, and controlling the drying time within 30 minutes to prevent the oxidation loss of effective ingredients; using a small grinder to grind the drained blueberry wine residue into powder, passing it through a 60-mesh sieve to make the wine residue particle size uniform, intermittently grinding to control the temperature to prevent the denaturation of antioxidants due to frictional heat, placing it in an ultrasonic device with a frequency of 40kHz, and ultrasonicating it at room temperature for 55 minutes for standby;

[0046] Step S2: blueberry wine fermentation,

[0047] Step S21, washing, selecting unbroken fresh blueberries, washing with potassium metabisulfite solution, picking out floating shrunken fruits and small fruits; stirring and washing the fresh blueberries with the potassium metabisulfite solution and soaking them for more than 15 minutes, wherein the mass percentage of potassium metabisulfite in the potassium metabisulfite solution is 0.05-0.08%;

[0048] Step S22, breaking, the slicer breaks the blueberry fruit into slices, the slicer breaks the blueberry fruit slices into slices, and the blueberry fruit thickness is 0.5 cm;

[0049] Step S23, adjusting the ingredients, loading the crushed blueberry pulp together with the juice into a sterilized 500L stainless steel fermentation tank, adding 150g / L yellow rock sugar, 100g / L honey, 0.03g / L pectinase, 0.03g / L compound yeast, and 3g / L yeast nutrient according to the volume of the stainless steel fermentation tank, and then adding citric acid or tartaric acid to make the pH value of the mixed system 3.3-3.8, mixing evenly, and obtaining a mixed system; the mass ratio of brewer's yeast, non-brewer's yeast RM12 and DE yeast is 1:0.25:0.5, and the pectinase is pectinesterase;

[0050] Step S24, temperature-controlled main fermentation: placing the mixed system obtained in step S23 for low-temperature fermentation at an ambient temperature of 14-16° C., and when the alcohol content reaches 6% vol (maximum fermentation rate), adding pitaya dregs to the fermentation tank at a volume ratio of 1:10 between pitaya dregs and blueberry slices, mixing well, and continuing fermentation under the same conditions;

[0051] Step S25, monitoring the fermentation progress: stirring the fermentation barrel once every two days, using a hydrometer, a PAL-1 handheld sugar meter, GB / T 15038-2006 "General Analysis Method for Wine", GB 5009.225-2016 "National Food Safety Standard for Ethanol Concentration in Wine", and measuring specific gravity, sugar content, acidity, alcohol content and other indicators to monitor the fermentation progress. When the specific gravity drops to nearly 1.100, the sugar content drops to below 170g / L and remains unchanged for a period of time, the acidity remains unchanged for a period of time, and a large number of bubbles are generated and gradually decrease within a period of time, it indicates that the main fermentation gradually stops;

[0052] Step S26, post-fermentation temperature control, after the main fermentation stops, the mixed system obtained in step S25 is placed in an environment of 18-22° C. for post-fermentation, so that the pitaya wine residues continue to extract redox substances and flavor components in the ethanol solution produced by the blueberry wine, the post-fermentation time lasts for 3 months, and the canning time is determined by continuous monitoring and regular tasting to obtain the first-grade blueberry wine;

[0053] Step S27, aging, pouring the blueberry wine obtained in step S26 into a new fermentation tank, aging for 6 months at 10-15° C. and 70% air humidity, removing the wine lees, and obtaining a blueberry wine intermediate;

[0054] Step S28, clarification and filtration: adding a composite clarifier to the blueberry wine intermediate obtained in step S27, leaving it for 10 days, clarifying the wine by natural sedimentation, and filtering to obtain clarified blueberry wine; the composite clarifier comprises pectinase and gelatin, and the mass ratio of pectinase to gelatin is 1:3;

[0055] Step S3, sterilization and canning, the filtered clarified blueberry wine is instantaneously sterilized and analyzed and then canned to obtain a finished blueberry wine.

[0056] 3. Determination of physical and chemical indicators of blueberry wine

[0057] 3.1. Detection of total colony count

[0058] According to the provisions of GB / T 27588-2011 "Liquor" on microorganisms, when the alcohol content is ≤24%vol, it shall be implemented in accordance with GB2758-2012 "Fermented wine and its blended wine". The total colony count determination is completed in accordance with GB 4789-2016 "National Food Safety Standard Food Microbiology Test Total Colony Count Determination".

[0059] 3.2 Determination of physical and chemical indicators

[0060] The soluble solids, pH value, total acid, volatile acid, SO2 content, etc. of blueberry wine were determined according to the series of methods in GB / T 15038-2006 General Methods for Analysis of Wine [5]. The alcohol content was determined according to GB 5009.225-2016 National Food Safety Standard for Ethanol Concentration in Wine. The methanol content was determined according to GB 5009-2016 National Food Safety Standard for Determination of Methanol in Food. The color difference of blueberry wine was determined using an LS 173 colorimeter.

[0061] 4. Determination of phenolic substances content

[0062] 4.1 Determination of anthocyanin content in blueberry wine

[0063] Using the pH differential method, take two 10mL volumetric flasks, add 1mL of blueberry wine sample to each, and use pH 1.0 (0.2mol / L KCl:0.2mol / L HCl=25:67 (V / V)) and pH 4.5 buffer solutions, make up to volume and mix evenly, let stand at 4°C for 2h, and measure the absorbance of the samples in pH 1.0 and pH 4.5 buffer solutions at wavelengths of 510nm and 700nm, respectively. The anthocyanin content is calculated using the following formula.

[0064] Anthocyanin content / (mg / L)=(A×449.2×n)×1000 / 26900;

[0065] Where: A is the absorbance difference at different pH values.

[0066] 4.2 Determination of total polyphenol content in blueberry wine

[0067] The Folin-ciocaileu method was used to measure the sample absorbance at a wavelength of 760 nm. The gallic acid standard was prepared into different concentrations, with the concentration C (μg / mL) as the horizontal axis and the absorbance A as the vertical axis. The measurement was repeated three times in parallel to draw the gallic acid standard curve. The regression equation of the standard curve was y=0.1399x+0.0045, R 2 =0.9991.

[0068] 4.3 Determination of total flavonoids content in blueberry wine

[0069] The NaNO3-Al(NO3)3 method was used to determine the sample absorbance at a wavelength of 510 nm. The rutin standard was prepared into different concentrations, with the rutin concentration C (μg / mL) as the horizontal axis and the absorbance A as the vertical axis. The measurement was repeated three times in parallel to draw the rutin standard curve. The regression equation of the standard curve was (y=8.0571x+0.4262, R 2 =0.9997.

[0070] 5. Determination of antioxidant capacity of blueberry wine

[0071] 5.1. Determination of DPPH free radical scavenging rate of blueberry wine

[0072] Determination of DPPH value free radical scavenging rate The DPPH free radical scavenging activity was determined according to the methods of Carmona-Jimenez et al. and Wang Chun et al. The absorbance Ai of sample solutions of different concentrations at 517 nm was measured by a spectrophotometer. Methanol was used instead of the sample in the control group to measure the absorbance A0. The formula for DPPH free radical scavenging rate is as follows.

[0073] DPPH free radical scavenging rate / % = [A0-(A i -A j )] / A0×100.

[0074] 5.2. Determination of ferric reducing ability (FRAP)

[0075] The iron ion reducing capacity was determined by referring to the method of RUPASINGHEHPV. The concentration of ferrous sulfate solution was used as the horizontal coordinate and the absorbance was used as the vertical coordinate. The standard curve was drawn by parallel determination for 3 times. The regression equation of the standard curve was y=0.6039x+0.0812, R 2=0.999.

[0076] 6. Volatile component analysis

[0077] 6.1 Extraction conditions

[0078] Take the blueberry wine and filter it. Pour the filtrate into a separatory funnel, add 20 mL of dichloromethane three times, shake it back and forth repeatedly for 5 minutes, place it on an iron stand and wait for stratification, prepare a volumetric flask for collection, open the valve of the separatory funnel, take the lower dichloromethane phase, combine and collect the dichloromethane phases extracted three times, remove the upper aqueous phase, add anhydrous sodium sulfate to dry, wait until it is fully dried, pour it into a rotary bottle, concentrate it to 1 mL on a rotary evaporator, filter it with a 0.22 μm needle filter organic membrane, and provide GC-MS analysis.

[0079] 6.2 Gas Chromatography Conditions

[0080] Capillary column VF-WaX (30m×0.25mm×0.25μm); injection port temperature 250℃; carrier gas helium; flow rate 1mL / min; injection volume 2μL; column temperature program: 60℃ for 3min,

[0081] The temperature was raised to 120°C at 6°C / min and maintained for 2 min, then raised to 230°C at 8°C / min and maintained at this temperature for 20 min. The ion source temperature was 230°C; the transfer line temperature was 250°C; and the scanning range was m / z 40-450.

[0082] 7. Data processing

[0083] Origin 2024 was used for drawing, SPSS23.0 was used for data processing, and the results were expressed as mean ± standard deviation. One-way ANOVA, Duncan's new multiple range method and Pearson correlation analysis were used, and P < 0.05 indicated significant differences.

[0084] Embodiment 2 to Embodiment 9

[0085] In order to investigate the optimal components and optimal ratios of the composite yeast, Examples 2 to 9 differ from Example 1 in that the components and ratios of the composite yeast, other components, brewing methods and determination methods of Examples 2 to 9 are the same as those of Example 1, and indicators such as soluble solids of composite yeast with different composition ratios are shown in Table 1.

[0086] Table 1 Soluble solids and other indicators in Examples 2 to 9

[0087]

[0088] As can be seen from Table 1 above, during the fermentation of a single or composite yeast, the soluble solids precipitated are less. The soluble solids produced by the fermentation of a single brewer's yeast are only 7.34 g / L, the alcohol content is also lower than 10% vol, and the sugar content is higher than 170 g / L. The soluble solids content of the fermentation containing three fermentation yeasts is all above 8.7 g / L. In addition, due to the addition of pitaya residue, the fermentation process has the characteristics of a long cycle, a low alcohol content, and incomplete conversion of sugar content consumption, which leads to increased pressure on the fermentation system. The use of mixed fermentation can well alleviate the fermentation pressure, increase the fermentation speed and ensure complete fermentation. According to the main indicator soluble solids content preferred embodiment 1, brewer's yeast: non-brewer's yeast RM12: DE yeast: =1:0.25:0.5.

[0089] Example 10 to Example 13

[0090] In order to investigate the optimal volume ratio of pitaya wine residue to blueberry, Examples 10 to 13 differ from Example 1 in the following: the volume ratio of pitaya wine residue to blueberry. Other components, brewing methods and determination methods of Examples 10 to 13 are the same as those of Example 1. Indicators such as soluble solids of pitaya wine residue to blueberry at different volume ratios are shown in Table 2.

[0091] Table 2 Indicators of soluble solids in Examples 10 to 13

[0092]

[0093] As can be seen from Table 2, according to the soluble solid content, the optimal volume ratio is 1:10, at which the sugar content can reach 159.00 g / L, because a large amount of dregs contain substances such as cellulose that cannot be decomposed, which occupies the fermentation space of blueberry wine. According to the preferred embodiment 1 of the main indicator soluble solid content, the volume ratio of pitaya dregs to blueberries is 1:10.

[0094] Example 14 to Example 19

[0095] In order to investigate the optimal components and optimal ratios of the composite clarifier, Examples 14 to 19 differ from Example 1 in that the components and ratios of the composite clarifiers, other components, brewing methods and measurement methods of Examples 14 to 19 are the same as those of Example 1, and indicators such as soluble solids of different composite clarifiers are shown in Table 3.

[0096] Table 3 Soluble solids and other indicators in Examples 14 to 19

[0097] Example Composite clarifier Proportion L* Value a* value b* value ΔE value Embodiment 14 Pectinase 1 19.65 2.1 -2.34 — Embodiment 15 Pectinase and Gelatin 2:1 19.61 2.11 -2.35 0.32 Example 16 Pectinase and Gelatin 1:1 19.41 2.07 -2.21 0.27 Embodiment 17 Pectinase and Gelatin 1:2 19.55 2.04 -2.27 0.14 Example 1 Pectinase and Gelatin 1:3 19.66 2.18 -2.33 0.08 Embodiment 18 Pectinase and Gelatin 1:3.5 19.57 2.13 -2.33 0.09 Embodiment 19 Pectinase and Gelatin 1:4 19.49 2.11 -2.29 0.17

[0098] It can be seen from Table 3 above that when a single pectinase is used as a clarifier as a control, when the proportion of gelatin increases, the chromaticity of the blueberry wine changes, and the a* value increases, indicating that its color is far away from red. When the proportion of pectinase increases, the L* value shows a decreasing trend, and the ΔE value gradually decreases. When the ratio exceeds 1:3, the ΔE value shows an increasing trend, indicating that the original chromaticity of the blueberry wine can be better presented at a ratio of 1:3. Therefore, the composite clarifier of Example 1, that is, the mass ratio of pectinase and gelatin is preferably 1:3.

[0099] Comparative Example 1

[0100] Comparative Example 1 and Examples 1 to 19 use the same brewing method; the difference is that: Comparative Example 1 does not add dragon fruit wine residue to participate in the fermentation, and other conditions are the same.

[0101] The blueberry wine (T) with added pitaya dregs prepared in Example 1 was compared with the original blueberry wine (CK) prepared in Comparative Example 1, and the antioxidant reducing substances content of the two were compared as follows: Figure 1 The comparison of the volatile aroma component contents of the two is shown in Table 4.

[0102] Table 4 Volatile aroma component content of Example 1 and Comparative Example 1

[0103]

[0104] Depend on Figure 1 It can be seen that in the test results of antioxidant reducing substances in blueberry wine after adding pitaya dregs, the contents of total flavonoids, total polyphenols and anthocyanins increased by 16.09%, 14.60% and 3.28% respectively.

[0105] As can be seen from Table 4, esters are the most abundant and important components, which are mainly produced during the fermentation and aging period. During this period, some substances can also be transformed because of partial acidic hydrolysis and oxidation. A large number of esters are formed after the fermentation of fruit wine. The precursor components of esters are fermented by microorganisms, and more esters are generated. A variety of esters make the aroma mellow and diverse. Ethyl esters with carbon chain lengths generally between C4-C10 give fruit wine a charming fruity aroma. Although the content of other esters is not high, they add rich flavor to the aroma of the wine.

[0106] Alcohol substances are mainly cedarwood alcohol, pinene alcohol, etc., among which cedarwood alcohol has a wide range of pharmacological effects, such as anti-inflammatory, antibacterial, sedative, anti-spasmodic, anti-cardiovascular disease, anti-aging and anti-tumor, etc. Pinene alcohol can be used for anti-oxidation and anti-inflammatory in vitro, and effectively improve high-fat diet, indicating that adding pitaya wine residue under compound fermentation conditions can effectively improve the health value of blueberry wine.

[0107] Aldehydes and ketones can give blueberry wine a unique aroma. Among them, 6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-carboxaldehyde can be used as an antitumor agent. The phenolic substances after sterilization are mainly 2,5-di-tert-butylphenol, which has a strong alkylphenol smell and can play a good bactericidal role; and the strong antioxidant and antibacterial effects of phenolic substances can play a very high role in preserving fruit wine. Tetradecamethylcycloheptasiloxane, hexamethylcyclotrisiloxane, etc. are a kind of volatile alkylene oxide mixture, which is often used in food additives to improve the emulsification properties of food, so that oil and water can be better mixed, and the texture and stability of food can be improved. In the fermentation of blueberry wine, it mainly plays a role in making the wine transparent and uniform in texture, and the taste is dense and smooth. Most of these similar components with more than ten carbons can form esters, and their existence alone has little effect on the aroma components of fruit wine. Other ingredients such as 2,6-dimethylnaphthalene will not have adverse effects on the wine if the content is moderate. However, if the content is greater than the threshold, it will have a certain impact on food safety. For example, it may cause cumulative damage to the liver and kidneys, and has potential carcinogenicity and teratogenicity, which will increase the risk of cancer and fetal malformations. Therefore, this item is included in the special inspection to avoid excessive content of this volatile ingredient.

[0108] Therefore, the blueberry wine with pitaya lees added prepared in Example 1 uses pitaya lees as an auxiliary material to participate in the blueberry wine fermentation process, and adopts a low-temperature full-monitoring fermentation mode. A total of 35 volatile aroma components are detected in the finished blueberry wine, including 13 ester substances, with a large number of effective ingredients, and the physical and chemical indicators meet the requirements. The antioxidant active substances are significantly improved compared with the single blueberry wine.

[0109] In summary, the brewing method of the present invention is simple and has the following advantages:

[0110] (1) In the brewing method of the present invention, the dragon fruit wine residue after ultrasonic treatment is selected as the auxiliary substrate, and the blueberry slices are fermented together, which not only increases the content of anthocyanins, total polyphenols and other antioxidant active substances in the finished blueberry wine, but also increases the volatile aroma components in the finished blueberry wine; in addition, the composite clarifier is used, which has a good clarification effect on the composite fermentation system and enriches the taste of the finished blueberry wine;

[0111] (2) In the brewing method of the present invention, pitaya wine residue is used as a co-substrate to carry out composite fermentation with sliced ​​blueberry fruit, so as to recycle the wine residue resources, further explore the antioxidant active substances rich in the wine residue waste, and improve the resource utilization rate;

[0112] (3) In the brewing method of the present invention, the taste and flavor of blueberry wine can be retained to the greatest extent through continuous low-temperature fermentation, and there is no blending in the brewing process, which retains the original aroma components of blueberries during fermentation and enriches the types of flavor substances.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for brewing blueberry wine by adding pitaya wine residue to assist fermentation, characterized in that: The specific steps include: Step S1, pretreatment of pitaya wine residue, quickly washing the blueberry wine residue after preliminary filtration with distilled water to remove sugar, alcohol and impurities attached to the surface to prevent microbial growth; then spreading it on a clean gauze, draining the water naturally, turning it over in time during the process to ensure uniform drying, and controlling the drying time within 30 minutes to prevent the oxidation loss of effective ingredients; using a small grinder to grind the drained blueberry wine residue into powder, passing it through a 60-mesh sieve to make the wine residue particles uniform in size, intermittently grinding to control the temperature to prevent the denaturation of antioxidants due to frictional heat, placing it in an ultrasonic device, ultrasonicating it at room temperature for 55 minutes, and setting it aside; Step S2, blueberry wine fermentation; Step S3, sterilization and canning, the filtered blueberry wine is instantaneously sterilized and analyzed and then canned to obtain blueberry wine; Wherein, the step S2 specifically includes the following steps: Step S21, washing: selecting unbroken fresh blueberries, washing them with a potassium metabisulfite solution, and picking out floating shrunken fruits and small fruits; Step S22: crushing: a slicer cuts and crushes the blueberry fruit into slices; Step S23, adjusting the ingredients, putting the crushed blueberry pulp into a sterilized stainless steel fermentation tank, adding yellow crystal sugar, honey, pectinase, compound yeast, yeast nutrient, adjusting the acidity, and mixing evenly to obtain a mixed system; Step S24, temperature-controlled main fermentation: placing the mixed system obtained in step S23 in an environment of 14-16° C. for low-temperature fermentation, using a hydrometer to measure the alcohol content, and when it reaches 6% vol, adding dragon fruit wine residue to the fermentation tank, mixing well, and continuing to ferment under the same conditions; Step S25, monitoring the fermentation process, monitoring the fermentation progress by measuring specific gravity, sugar content, acidity and alcohol content, and determining whether the main fermentation has stopped; Step S26, post-fermentation temperature control, after the main fermentation stops, the mixed system obtained in step S25 is placed in an environment of 18-22° C. for post-fermentation, so that the pitaya wine residues continue to extract redox substances and flavor components in the ethanol solution produced by the blueberry wine, the post-fermentation time lasts for 3 months, and the canning time is determined by continuous monitoring and regular tasting to obtain the first-grade blueberry wine; Step S27, aging, pouring the blueberry wine obtained in step S26 into a new fermentation tank, aging for 6 months at 10-15° C. and 70% air humidity, removing the lees, and obtaining a blueberry wine intermediate; Step S28, clarification and filtration: adding a composite clarifier to the blueberry wine intermediate obtained in step S27, leaving it for 10 days, clarifying the wine by natural sedimentation, and filtering to obtain clarified blueberry wine; Step S3, sterilization and canning, the filtered clarified blueberry wine is instantaneously sterilized and analyzed and then canned to obtain a finished blueberry wine.

2. The method for brewing blueberry wine with dragon fruit lees added to assist fermentation according to claim 1, characterized in that: In the step S21, the mass percentage of potassium pyrosulfite in the potassium pyrosulfite solution is 0.05-0.08%.

3. The method for brewing blueberry wine with dragon fruit dregs added to assist fermentation according to claim 1, characterized in that: In step S22, the thickness of the blueberry fruit slices is 0.5 cm.

4. The method for brewing blueberry wine with dragon fruit dregs added to assist fermentation according to claim 1, characterized in that: In step S23, the mass ratio of blueberry pulp, yellow crystal sugar, honey, pectinase, compound yeast and yeast nutrient is 1000:150:100:10:10:3; the acidity is adjusted by adding citric acid or tartaric acid to adjust the pH value of the mixed system to 3.3-3.

8.

5. The method for brewing blueberry wine with dragon fruit dregs added to assist fermentation according to claim 1, characterized in that: In the step S23, the pectinase is one of pectinesterase, protopectinase, polygalacturonase and pectin lyase.

6. The method for brewing blueberry wine with dragon fruit dregs added to assist fermentation according to claim 1, characterized in that: In the step S23, the composite yeast includes brewer's yeast, non-brewer's yeast RM12 and DE yeast, and the mass ratio of brewer's yeast, non-brewer's yeast RM12 and DE yeast is 1: (0.25-1): (0.25-1).

7. The method for brewing blueberry wine with dragon fruit dregs added to assist fermentation according to claim 1, characterized in that: In step S24, the volume ratio of blueberry pulp to pitaya residue is 1:(10-20).

8. The method for brewing blueberry wine with dragon fruit dregs added to assist fermentation according to claim 1, characterized in that: In step S25, the specific operation of monitoring the fermentation process is: stirring the fermentation barrel once every two days. When the specific gravity drops to 1.100, the sugar content drops to 170g / L, and a large number of bubbles are generated and gradually decrease, it indicates that the main fermentation gradually stops.

9. The method for brewing blueberry wine with dragon fruit dregs added to assist fermentation according to claim 1, characterized in that: In the step S28, the composite clarifier includes pectinase and gelatin, and the mass ratio of pectinase to gelatin is 1:(2-5).

10. A blueberry wine with dragon fruit dregs added to assist fermentation, characterized in that: The blueberry wine is prepared by the brewing method according to any one of claims 1 to 9.

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