A method for brewing blackcurrant wine

Abstract

The application discloses a kind of blackcurrant ice wine brewing method, it is related to the technical field of food engineering.The method comprises the following steps: raw material pretreatment, blackcurrant fresh fruit fermentation, ice grape fermentation, mixed aging and clarification, filling finished product.The method overcomes the defects of low utilization rate of blackcurrant fresh fruit, complex fermentation flavor conflict, poor nutrient retention and unstable alcohol content in the prior art;It improves the sour taste of blackcurrant fruit wine, and the fresh fruit polyphenol retention rate is more than 80%, while retaining the rich fruit aroma of ice grape;Solve the problem of low juice yield of fresh fruit in the single fermentation process, so that the juice yield of blackcurrant fresh fruit is greater than or equal to 65%;Ensure that the alcohol content of finished product is stable at 10%-11%, the flavor is soft and coordinated, and meets the high-end ice wine standard.

Description

Technical Field

[0001] This invention relates to the technical field of food engineering, specifically a method for brewing black chokeberry ice wine. Background Technology

[0002] Black chokeberry fresh fruit is rich in anthocyanins, proanthocyanidins, and other polyphenolic active ingredients, with a total polyphenol content of 22-32g / kg. The active ingredients are more fully preserved when the fruit is fresh. However, when used alone for winemaking, its high tannin content can result in a rough and astringent taste, and a thin aroma profile. Ice grapes, on the other hand, are characterized by high sugar content (250-300g / L) and rich fruit aromas (pear and citrus-like aroma compounds), making them a core ingredient in traditional high-end ice wines. However, they suffer from a lower polyphenol content (only 5-8g / kg).

[0003] Existing blended ice wine brewing techniques have significant drawbacks: First, most processes involve fermenting dried black chokeberry or its juice with ice grapes, neglecting the advantages of the active ingredients in fresh fruit. Furthermore, blended fermentation can lead to a conflict between the astringency of black chokeberry and the fruity aroma of ice grapes, with polyphenol oxidation exceeding 35%. Second, a few attempts at single-fermentation processes have failed to optimize parameters for the characteristics of fresh black chokeberry, resulting in low juice yield (less than 55%) and severe damage to nutrients during fermentation. Third, the finished product exhibits large fluctuations in alcohol content (9-14%) and poor flavor stability, making it difficult to meet the quality requirements of high-end ice wine. Summary of the Invention

[0004] To address the aforementioned problems, specifically those raised in the background section, this invention proposes a method for brewing black chokeberry ice wine, the specific technical solution of which is as follows: A method for making black chokeberry ice wine, the method comprising the following steps: Raw material pretreatment: Select fresh black chokeberry fruit and ice grapes, screen the fresh fruit of appropriate size, and perform fresh fruit color protection treatment on the black chokeberry fruit to complete the raw material pretreatment; Fermentation of fresh black chokeberry: After color protection, fresh black chokeberry is pressed at low temperature, tannins and pectinase are added for enzymatic hydrolysis to reduce astringency, and then fermented with low-temperature resistant yeast to obtain fermented black chokeberry wine. Fermented ice grapes: Ice grapes are pressed at low temperatures, and pectinase and β-glucosidase are added for enzymatic hydrolysis and aroma enhancement. Yeast is then inoculated for fermentation to obtain fermented ice grape wine. Blending and clarification: Black chokeberry fermented wine and ice grape fermented wine are blended and stirred evenly, sulfur dioxide is added for aging, and after aging, the wine is clarified and filtered to obtain a clarified liquid, which is then bottled into brown light-proof glass bottles to complete the production of black chokeberry ice wine.

[0005] Furthermore, in step (1), after the black chokeberry fruit matures in October-November each year, select fresh fruit without mold or damage, and complete the processing within 24 hours after harvesting to avoid spoilage of the fresh fruit; select ice grapes with a minimum temperature of ≤-8℃ for 3 consecutive days during the same period, and the fruit branches are naturally frozen for more than 24 hours, with the temperature throughout the process ≤-5℃; select black chokeberry fresh fruit with a diameter of 8mm or more, and ice grapes with a diameter of 10mm or more, and remove impurities and unqualified fruit respectively; add 0.02% vitamin C solution to the black chokeberry fresh fruit and soak for 10 minutes to prevent oxidation and browning of the fresh fruit, and drain the water for later use.

[0006] Further, in step (2), the fresh black chokeberry fruit is placed in a pressing device at -3℃ to -5℃, and the pressing juice is collected by gradient pressure. Tanninase and pectinase are added to the pressing juice, and the mixture is enzymatically hydrolyzed at 15℃ for 3 hours. The mixture is stirred once every 1 hour, and potassium metabisulfite is added to make the sulfur dioxide reach 65mg / L. After standing for 10 hours, NW-3 low-temperature resistant yeast is inoculated, and fermentation is carried out at 14-16℃ for 7-8 days. The specific gravity is measured daily during the period until the specific gravity stabilizes, and black chokeberry fermented wine is obtained.

[0007] Furthermore, the gradient pressurization process specifically involves initially maintaining a pressure of 0.3 MPa for 10 minutes, then increasing to 0.6 MPa and maintaining it for 20 minutes, resulting in a juice yield of ≥65%. The amount of tanninase added is 0.015 g / L, the amount of pectinase added is 0.02 g / L, the stirring rate is 50 r / min, the inoculation amount of NW-3 low-temperature resistant yeast is 180 mg / L, the specific gravity stability condition is a change of ≤0.002 over 24 hours, and the resulting black chokeberry fermented wine has an alcohol content of 9-10%.

[0008] Furthermore, in step (3), the ice grapes are placed in a pressing device at -4℃ to -6℃ and pressed at a constant pressure of 0.4MPa for 35 minutes. The pressed juice is collected, and pectinase and β-glucosidase are added. The mixture is enzymatically hydrolyzed at 18℃ for 2 hours, and stirred once every 30 minutes. Potassium metabisulfite is added to make the free sulfur dioxide reach 70mg / L. After standing for 12 hours, SY-2 yeast is inoculated and fermented at 18-20℃ for 5-6 days until the specific gravity is stable, thus obtaining the ice grape fermented wine.

[0009] Furthermore, the amount of pectinase added is 0.04 g / L, the amount of β-glucosidase added is 0.01 g / L, the stirring rate is 40 r / min, the amount of SY-2 yeast inoculated is 220 mg / L, and the alcohol content of the resulting ice grape fermented wine is 12-13%.

[0010] Further, in step (4), the fermented black chokeberry wine and the fermented ice grape wine are mixed in a mass ratio of 3:7-4:6 and stirred at a speed of 60r / min for 5min until they are evenly mixed. Sulfur dioxide is added to the mixed wine until the final concentration is ≤50mg / L. The wine is then transferred to a French medium-toasted oak barrel and aged at 6-8℃ for 10-12 months. The wine is decanted every 45 days to remove the lees. After that, the wine is frozen and left to stand at -4℃ for 20 days. Then, 0.2g / L of bentonite is added and stirred evenly. The wine is left to stand for 5 days and filtered through a 0.45μm precision filter membrane to obtain a clear wine. The clear wine is then bottled into brown light-proof glass bottles under a Class 10,000 cleanroom sterile environment to obtain black chokeberry ice wine.

[0011] The beneficial technical effects of this invention are as follows: it overcomes the defects of low utilization rate of fresh black chokeberry fruit, conflicting flavors from compound fermentation, poor nutrient retention, and unstable alcohol content in the prior art; it increases the polyphenol retention rate of fresh black chokeberry fruit to over 80%, while retaining the rich fruity aroma of ice grapes; it solves the problem of low juice yield of fresh fruit in the single fermentation process, making the juice yield of fresh black chokeberry fruit ≥65%; and it ensures that the alcohol content of the finished product is stable at 10.0%-11.0%, with a mellow and harmonious flavor that meets the standards of high-end ice wine. Attached Figure Description

[0012] Figure 1 This is an analytical diagram of the gas chromatography-mass spectra of black chokeberry ice wine prepared according to one embodiment of the present invention. Figure 2 A graph showing the flavonoid content in black chokeberry ice wine prepared according to one embodiment of the present invention; Figure 3 A graph showing the anthocyanin content of black chokeberry ice wine prepared according to one embodiment of the present invention; Figure 4 The graph shows the total phenol content of black chokeberry ice wine prepared according to one embodiment of the present invention. Detailed Implementation

[0013] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0014] This invention provides a method for brewing black chokeberry ice wine, the specific method of which is as follows: 1. Raw material pretreatment process Raw material harvesting and screening: Black chokeberry fresh fruit: After the fruit ripens in October-November each year, select fresh fruit that is free from mold and damage, and complete the processing within 24 hours after harvesting to avoid spoilage. Ice grapes: Harvest when the minimum temperature is ≤-8℃ for 3 consecutive days, and the fruit is naturally frozen on the vine for more than 24 hours, with the temperature throughout the process ≤-5℃; Screening: Fresh black chokeberries were screened using an 8mm aperture stainless steel sieve, and frozen grapes were screened using a 10mm aperture sieve to remove impurities and unqualified fruits.

[0015] Color preservation treatment for fresh fruit: Soak fresh black chokeberry fruit in a 0.02% vitamin C solution for 10 minutes to prevent oxidation and browning. Then drain the water to maintain the freshness of the fruit.

[0016] 2. Separate fermentation process Fermentation process of fresh black chokeberry: Low-temperature pressing: The color-protected fresh black chokeberry fruit is placed in a pressing device at -3℃ to -5℃, and gradient pressure is applied (initially 0.3MPa for 10 min, then increased to 0.6MPa for 20 min). The pressing juice is collected, and the juice yield is ≥65%. Enzymatic hydrolysis to reduce astringency: Add tanninase (0.015 g / L) and pectinase (0.02 g / L) to the pressed juice, and hydrolyze at 15°C for 3 hours, stirring once every 1 hour (speed 50 r / min). Inoculation and Fermentation: Add potassium metabisulfite to achieve a free sulfur dioxide concentration of 65 mg / L. After standing for 10 hours, inoculate with NW-3 low-temperature resistant yeast (inoculation amount 180 mg / L). Ferment at 14-16℃ for 7-8 days, measuring the specific gravity daily until it stabilizes (24-hour change ≤ 0.002), yielding black chokeberry fermented wine (alcohol content 11%-12%). Ice Grape Fermentation Process: Low-temperature pressing: Place the frozen grapes in a pressing device at -4℃ to -6℃ and press at a constant pressure of 0.4MPa for 35 minutes. Collect the pressed juice, with a juice yield of ≥50%. Enzymatic hydrolysis for aroma enhancement: Add pectinase (0.04 g / L) and β-glucosidase (0.01 g / L), and hydrolyze at 18°C ​​for 2 hours, stirring once every 30 minutes (at a rate of 40 r / min). Inoculation and fermentation: Add potassium metabisulfite to make the free sulfur dioxide reach 70 mg / L, let stand for 12 hours, then inoculate with SY-2 yeast (inoculation amount 220 mg / L), ferment at 18-20℃ for 5-6 days until the specific gravity is stable, and obtain ice grape fermented wine (alcohol content 12%-13%).

[0017] 3. Blended aging and clarification process Blending: Mix black chokeberry fermented wine and ice grape fermented wine in a mass ratio of 3:7-4:6 and stir well (speed 60r / min, time 5min). Aging process: Add sulfur dioxide to the mixed wine to a final concentration of ≤50mg / L, transfer to medium-toasted French oak barrels, age at 6-8℃ for 10-12 months, decanting every 45 days to remove lees; Clarification and filtration: After aging, freeze at -4℃ for 20 days, then add 0.2g / L bentonite and stir well. Let stand for 5 days, and finally filter with a 0.45μm precision filter membrane to obtain a clear wine.

[0018] In a Class 10,000 cleanroom environment, the clarified wine is bottled into brown, light-proof glass bottles to obtain the finished ice wine made by fermenting fresh black chokeberry fruit and ice grapes separately.

[0019] Black chokeberry ice wine was prepared following the steps outlined above. Parameter testing revealed a polyphenol retention rate of 88-92%, with a total polyphenol content ≥5.2g / L, representing an improvement of over 40% compared to traditional mixed fermentation processes. The total fruit aroma compounds in the finished ice wine reached 1300-1600μg / L, significantly reducing the astringency of black chokeberry. The juice yield from fresh black chokeberry fruit reached 65%-68%, and the alcohol content remained stable at 10%-11%, with fluctuations ≤0.5%vol. The total acid content was 12.0-13.0g / L, the total sugar content was 191.0-194.7g / L, and the volatile acid content was 0.76-0.78g / L.

[0020] The black chokeberry ice wine prepared by the above method was tested to determine the content of its aromatic components. The results are shown in Table 1. Table 1. Analysis of Aromatic Component Spectra

[0021] Flavor analysis: 34 aromatic components were identified, including 5 alcohols (23.33% of peak area), 4 esters (4.79% of peak area), 5 aldehydes (26.58% of peak area), 10 ketones (22.56% of peak area), 7 acids (16.44% of peak area), and 3 other compounds (6.3% of peak area). The aroma is rich and layered. Aldehydes (26.58%), alcohols (23.33%), and ketones / furanones (15.01%) are the core components, with prominent caramel, sweet, and toasty aromas, consistent with the sweet style of ice wine. Esters, acids, and alkanes are well-balanced, resulting in excellent flavor harmony, making this a distinctive and richly flavorful blended wine.

[0022] The gas chromatography-mass spectrometry (GC-MS) analysis of the black chokeberry ice wine prepared by the method described in this invention yielded the following results: Figure 1 As shown.

[0023] The total active ingredient content is as follows: Total phenol content: 2.30-2.40 g / L; total anthocyanin content: 320-330 mg / L; total flavonoids: 260-270 mg / L. Specific chromatograms are shown below. Figure 2 , Figure 3 and Figure 4 As shown.

[0024] Sensory experiments were conducted on the prepared black chokeberry ice wine. 100 participants were selected to taste it. The final sensory score was above 9.1, and the astringency of the black chokeberry was significantly reduced, resulting in a smooth and mellow taste.

[0025] Economically, this will drive the shift of black chokeberry fresh fruit from low-lying, cold-water-grown varieties to high-end, long-term-harvesting products, increasing the economic value of raw materials by more than 35%.

[0026] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0027] In the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.

[0030] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method of brewing a blackcurrant ice wine, characterized by: The method includes the following steps: Raw material pretreatment: Select fresh black chokeberry fruit and ice grapes, screen the fresh fruit of appropriate size, and perform fresh fruit color protection treatment on the black chokeberry fruit to complete the raw material pretreatment; Fermentation of fresh black chokeberry: After color protection, fresh black chokeberry is pressed at low temperature, tannins and pectinase are added for enzymatic hydrolysis to reduce astringency, and then fermented with low-temperature resistant yeast to obtain fermented black chokeberry wine. Fermented ice grapes: Ice grapes are pressed at low temperatures, and pectinase and β-glucosidase are added for enzymatic hydrolysis and aroma enhancement. Yeast is then inoculated for fermentation to obtain fermented ice grape wine. Blending and clarification: Black chokeberry fermented wine and ice grape fermented wine are blended and stirred evenly, sulfur dioxide is added for aging, and after aging, the wine is clarified and filtered to obtain a clarified liquid, which is then bottled into brown light-proof glass bottles to complete the production of black chokeberry ice wine.

2. The method of claim 1, wherein the black chokeberry ice wine is characterized by: In step (1), after the black chokeberry fruit matures in October-November each year, select fresh fruit without mold or damage, and complete the processing within 24 hours after harvesting to avoid spoilage. Select ice grapes with a minimum temperature of ≤-8℃ for 3 consecutive days during the same period and with the fruit branches naturally frozen for more than 24 hours, with the temperature throughout the process ≤-5℃. Select black chokeberry fresh fruit with a diameter of 8mm or more and ice grapes with a diameter of 10mm or more, and remove impurities and unqualified fruit respectively. Soak the black chokeberry fresh fruit in 0.02% vitamin C solution for 10 minutes to prevent oxidation and browning, and drain the water for later use.

3. The method of claim 1, wherein the black chokeberry ice wine is characterized by: In step (2), fresh black chokeberry fruit is placed in a pressing device at -3℃ to -5℃, and gradient pressure is used to collect the pressing juice. Tanninase and pectinase are added to the pressing juice, and the mixture is enzymatically hydrolyzed at 15℃ for 3 hours. The mixture is stirred once every 1 hour, and potassium metabisulfite is added to make the sulfur dioxide reach 65mg / L. After standing for 10 hours, NW-3 low-temperature resistant yeast is inoculated, and fermentation is carried out at 14-16℃ for 7-8 days. The specific gravity is measured daily during the fermentation period until the specific gravity stabilizes, and black chokeberry fermented wine is obtained.

4. The method of claim 3, wherein the black chokeberry ice wine is characterized by: The gradient pressurization process specifically involves initially maintaining a pressure of 0.3 MPa for 10 minutes, then increasing to 0.6 MPa and maintaining it for 20 minutes, resulting in a juice yield of ≥65%. The amount of tanninase added is 0.015 g / L, the amount of pectinase added is 0.02 g / L, the stirring rate is 50 r / min, the inoculation amount of NW-3 low-temperature resistant yeast is 180 mg / L, and the specific gravity stability condition is a change of ≤0.002 over 24 hours. The resulting black chokeberry fermented wine has an alcohol content of 9-10%.

5. The method for brewing black chokeberry ice wine according to claim 1, characterized in that: In step (3), the ice grapes are placed in a pressing device at -4℃ to -6℃ and pressed at a constant pressure of 0.4MPa for 35 minutes. The pressed juice is collected, and pectinase and β-glucosidase are added. The mixture is enzymatically hydrolyzed at 18℃ for 2 hours, and stirred every 30 minutes. Potassium metabisulfite is added to make the free sulfur dioxide reach 70mg / L. After standing for 12 hours, SY-2 yeast is inoculated and fermented at 18-20℃ for 5-6 days until the specific gravity is stable, thus obtaining the ice grape fermented wine.

6. The method for brewing black chokeberry ice wine according to claim 5, characterized in that: The amount of pectinase added was 0.04 g / L, the amount of β-glucosidase added was 0.01 g / L, the stirring rate was 40 r / min, the amount of SY-2 yeast inoculated was 220 mg / L, and the alcohol content of the resulting fermented ice grape wine was 12-13%.

7. The method for brewing black chokeberry ice wine according to claim 1, characterized in that: In step (4), the fermented black chokeberry wine and the fermented ice grape wine are mixed in a mass ratio of 3:7-4:6 and stirred at 60r / min for 5min until uniform. Sulfur dioxide is added to the mixed wine until the final concentration is ≤50mg / L. The wine is then transferred to French medium-toasted oak barrels and aged at 6-8℃ for 10-12 months. The wine is decanted every 45 days to remove lees. After that, the wine is frozen and left to stand at -4℃ for 20 days. Then, 0.2g / L of bentonite is added and stirred until uniform. The wine is left to stand for 5 days and filtered through a 0.45μm precision filter membrane to obtain a clear wine. The clear wine is then bottled into brown light-proof glass bottles under a Class 10,000 cleanroom aseptic environment to obtain black chokeberry ice wine.

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