A brewing method for improving the color stability of red wine

Abstract

The present invention relates to the field of winemaking technology, and more specifically, to a method for improving the color stability of red wine. After red grapes are added to a fermentation tank, white grape seeds are added to the fermentation tank, followed by cold maceration and fermentation to produce red wine. This method, using white grape seeds as a secondary coloring ingredient, provides an additional source of flavanols and condensed tannins for the red wine. This method effectively mitigates the rapid loss of red hue during aging and significantly deepens the color of red wine, particularly red hues. The white grape seeds used in this method are those from the skins and pomace obtained from the brewing of dry white wine. This method not only eliminates the need to obtain white grape seeds but also allows for the reuse of the skins and pomace produced during the white wine brewing process.

Description

Technical Field

[0001] The present invention relates to the technical field of wine brewing, and in particular to a brewing method for improving the color stability of red wine. Background Art

[0002] Color is a key sensory quality of red wine, primarily determined by the composition and content of phenolic compounds, and is a crucial factor in consumer purchasing decisions. However, domestic red wines, and even other berry wines, suffer from a rapid loss of red hue, significantly reducing the product's market life and value.

[0003] Anthocyanins are the main coloring substances in red wine, but monomeric anthocyanins and acylated anthocyanins from grapes are very unstable. During the fermentation and aging process, they rapidly degrade or react with other compounds (such as pyruvic acid, acetaldehyde, phenolic acid, flavan-3-ols, etc.) to form relatively stable wine pigments. Among them, the anthocyanin derivatives formed with flavan-3-ols have a purple-red hue.

[0004] In existing technologies, to improve the color stability of red wine, it is often necessary to add color enhancers. Common color enhancers include organic acids, amino acids, nucleotides, metal ions, alkaloids, and polyphenols. However, the addition of these color enhancers will have varying degrees of impact on other components of the wine, significantly increasing production costs and affecting the overall quality of the wine. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a brewing method for improving the color stability of red wine.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] The present invention provides a brewing method for improving the color stability of red wine. After red grape raw materials are added into a fermentation tank, white grape seeds are added into the fermentation tank, and then cold soaking and fermentation are performed to obtain red wine.

[0008] Furthermore, the white grape seeds are white grape seeds separated from the skins and residues obtained during the brewing of dry white wine.

[0009] Furthermore, the mass ratio of the white grape seeds to the red grape raw material is 3 to 7 g / kg.

[0010] Furthermore, the mass ratio of the white grape seeds to the red grape raw material is 5 g / kg.

[0011] Further, the following steps are included:

[0012] S1. Destemming, screening, and crushing red grapes to obtain the red grape raw material;

[0013] S2. Add the red grape raw material to the fermentation tank, and adjust the free SO2 to 50 mg / L; then add 20 mg / L of pectinase;

[0014] S3, adding the collected white grape seeds into the fermentation tank;

[0015] S4, cold soaking: the temperature of the cold soaking is 5-10°C;

[0016] S5, alcohol fermentation: After the cold soaking is completed, the temperature is adjusted to 25°C, yeast is inoculated, and alcohol fermentation is initiated; during the alcohol fermentation period, the temperature is 22-25°C;

[0017] S6, separating the skin and residue: squeezing the fermented liquor after the alcohol fermentation is completed, and then separating the skin and residue to obtain fermented wine;

[0018] S7, performing malic acid-lactic acid fermentation: adding lactic acid bacteria to the fermented wine to initiate malic acid-lactic acid fermentation, wherein the temperature of the malic acid-lactic acid fermentation is 24-26° C.;

[0019] S8. Free SO2 is adjusted to 35 mg / L, the malic acid-lactic acid fermentation is terminated, and the red wine is obtained.

[0020] Furthermore, in step S4, the cold soaking time is 7 days.

[0021] Furthermore, in step S5, the yeast inoculated is D254 yeast, and the inoculation amount is 200 mg / L.

[0022] Furthermore, in step S5, during the alcohol fermentation, the specific gravity of the fermentation liquid in the fermentation tank is measured. When the specific gravity drops below 1.000 and remains stable, the alcohol fermentation ends.

[0023] Furthermore, in step S7, the amount of lactic acid bacteria added is 6 mg / L.

[0024] Furthermore, in step S7, the malic acid-lactic acid fermentation is carried out for 20 to 30 days.

[0025] The beneficial effects of the present invention are:

[0026] (1) The brewing method for improving the color stability of red wine of the present invention uses white grape seeds as a secondary color raw material to provide an additional source of flavanols and condensed tannins for red wine, which can significantly deepen the color of red wine, especially the red hue;

[0027] (2) The brewing method for improving the color stability of red wine of the present invention can effectively improve the problem of rapid loss of red hue in red wine during aging, so that the red hue of red wine has good stability during aging;

[0028] (3) The method for improving the color stability of red wine according to the present invention uses white grape seeds from the skins and pomace obtained during the brewing of dry white wine. This not only eliminates the need for obtaining white grape seeds, but also allows the skins and pomace obtained during the brewing of white wine to be reused.

[0029] (4) The brewing method for improving the color stability of red wine of the present invention includes adding white grape seeds before cold maceration, and lightly pressing the white grape seeds and red grape raw materials simultaneously. This can promote the dissolution rate of flavanols and condensed tannins in the white grape seeds, and can also effectively integrate the dissolved flavanols and condensed tannins with the grape mash after pressing, thereby making the final red wine have a better color tone and a more complete body.

[0030] (5) The brewing method for improving the color stability of red wine of the present invention has the advantages of low cost, high efficiency and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The invention relates to a method for improving the color stability of red wine. The invention also relates to an embodiment of the invention wherein white grape seeds are added to the wine for fermentation to improve the color stability of the wine. Figure 1 A is the brightness L* value, Figure 1 In the figure, B is the red hue a* value. Figure 1 Middle C is the b* value of yellow hue;

[0032] Figure 2 The invention relates to a method for improving the color stability of red wine. The invention also relates to an example of adding white grape seeds to the wine for fermentation, which shows the effect on the content of monomeric anthocyanins in the wine. Figure 2 A is the total anthocyanin content, Figure 2 B is the content of non-acylated anthocyanin, Figure 2 C in the middle is the content of acetylated anthocyanin; Figure 2 D in the table is the content of coumaroyl anthocyanin;

[0033] Figure 3 The invention relates to a method for improving the color stability of red wine. The invention also relates to an example of adding white grape seeds to the fermentation process to determine the effect on the content of polymerized anthocyanins in the wine. Figure 3 A is the total polymerized anthocyanin content, Figure 3 Where B is the content of polymeric anthocyanins directly or indirectly connected to flavan-3-ols, Figure 3 The content of anthocyanin and flavanol polymers with ethyl / acetaldehyde bridges in C;

[0034] Figure 4 The invention relates to a method for improving the color stability of red wine. The invention also relates to an example of adding white grape seeds to the wine for fermentation, which shows the effect on the content of non-anthocyanin substances in the wine. Figure 4 Where A is the content of flavan-3-ol, Figure 4 B in the middle is the gallation rate, Figure 4 C is the content of flavonols; Figure 4 D is the content of phenolic acid;

[0035] Figure 5 The invention relates to a method for improving the color stability of red wine. The invention also relates to an example of adding white grape seeds to fermentation to determine the effect on the aroma content of the wine. Figure 5 A is the total aroma substance content, Figure 5 B is the content of ester substances, Figure 5 C is the content of alcohol substances, Figure 5 D is the content of aldehydes, Figure 5 E in the equation is the content of norisoprene aroma substances. Figure 5 F in the equation is the terpene aroma content. Figure 5 G in the formula is the content of acid substances. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0037] The brewing method for improving the color stability of red wine of the present invention comprises the following steps: adding red grape raw materials into a fermentation tank, adding white grape seeds into the fermentation tank, and then performing cold soaking and fermentation to obtain the red wine.

[0038] The brewing method of the present invention uses white grape seeds as a color-enhancing ingredient, providing an additional source of flavanols and condensed tannins for red wine. This effectively alleviates the rapid loss of red hue in red wine during aging. The addition of white grape seeds not only enhances color but also prevents excessive levels of flavanols and condensed tannins. Furthermore, as a natural ingredient, the addition of white grape seeds does not negatively impact the red wine, ensuring the high quality and safety of the red wine brewed using this method.

[0039] In the present invention, the white grape seeds can be directly isolated from white grape berries or from the discarded skins and pomace during white winemaking. However, directly isolating the white grape seeds from the white grape berries requires a separate white grape seed separation step, which reduces the efficiency and increases the cost of the present method, and also results in waste of the white grape berries.

[0040] Therefore, preferably, the white grape seeds used in the brewing method of the present invention are white grape seeds from the skins and pomace obtained from the brewing of dry white wine. This not only allows direct access to white grape seeds, but also allows the skins and pomace obtained during the white wine brewing process to be reused.

[0041] Preferably, the mass ratio of white grape seeds to red grape raw materials is 3-7 g / kg. Since white grape seeds are rich in flavanols and condensed tannins, if too much is added, the body of the red wine will contain too much tannin, causing a noticeable astringency and adversely affecting the sensory quality of the red wine. If too little is added, the color-enhancing effect cannot be achieved effectively.

[0042] In addition, although red winemaking is a dynamic process and the quality of the resulting red wine is also affected by the red grape raw materials and the fermentation process, the amount of white grape seeds added has been shown through experiments to provide a similar color-enhancing effect, even when different red grape varieties are used or the specific fermentation process is different. In other words, regardless of the specific red grape variety used or the specific fermentation conditions, the amount of white grape seeds used is generally within the above range.

[0043] More preferably, the mass ratio of the white grape seeds to the red grape raw material is 5 g / kg.

[0044] Preferably, the red wine of the present invention is a dry red wine. Although rosé wine may also require auxiliary coloring in some cases, since rosé wine does not require aging, the stability requirements for the red hue are relatively low, and no special auxiliary coloring is required. However, during the aging process of dry red wine, the body of the wine changes significantly, and the color changes significantly. Whether its red hue is stable is one of the important indicators for measuring its quality.

[0045] More preferably, the red grape varieties used in the present invention are Cabernet Sauvignon, Merlot, and Pinot Noir.

[0046] Preferably, the white grape seeds of the present invention are derived from Chardonnay or Gewürztraminer.

[0047] The brewing method of the present invention adds white grape seeds before cold soaking, and lightly squeezes the white grape seeds and red grape raw materials at the same time, which can promote the dissolution rate of flavanols and condensed tannins in the white grape seeds and effectively integrate the dissolved flavanols and condensed tannins with the grape mash after squeezing, so that the final red wine has a better color tone and a more complete body.

[0048] Preferably, the brewing method for improving the color stability of red wine of the present invention comprises the following steps:

[0049] S1. Destemming, berry screening, and crushing red grapes to obtain red grape raw materials.

[0050] Specifically, the red grapes are hand-picked at maturity and immediately transported to the brewery. They pass through a cluster sorting platform to remove rotten and diseased clusters and debris (such as leaves and insects). After a stemming machine removes the stems, they pass through a grape sorting platform to remove underripe grapes (such as pink grapes) and rotten grapes. Mature, intact, and healthy grapes are retained for feeding.

[0051] S2. Add the red grape raw material into the fermentation tank and adjust the free SO2 to 50 mg / L; then add 20 mg / L of pectinase (Optivin).

[0052] S3. Add the collected white grape seeds into the fermentation tank.

[0053] S4. Cold soaking: the temperature of the cold soaking is 5-10°C; the time of the cold soaking is 7 days.

[0054] S5. Alcoholic fermentation: After the cold soaking, the temperature was adjusted to 25° C., yeast was inoculated, and alcoholic fermentation was initiated; during the alcoholic fermentation, the temperature was 22-25° C.; the yeast inoculated was D254 yeast (Lallemand, France) at an inoculation amount of 200 mg / L.

[0055] During the alcoholic fermentation, the specific gravity of the fermentation liquid in the fermentation tank is measured. When the specific gravity drops below 1.000 and remains stable, the alcoholic fermentation is completed.

[0056] S6. Separating the skin and residue: Pressing the fermentation liquid after the alcohol fermentation is completed, and then separating the skin and residue to obtain fermented wine.

[0057] S7. Malolactic fermentation: Lactic acid bacteria ENARTIS-ML UNO (Enartis, Italy) were added to the fermented wine to initiate malolactic fermentation. The temperature of the malolactic fermentation was 24-26° C. The amount of lactic acid bacteria added was 6 mg / L. The malolactic fermentation lasted for 25 days.

[0058] S8. Adjust the free SO2 to 35 mg / L to terminate the malic acid-lactic acid fermentation and obtain red wine.

[0059] The method and effects of the present invention are described in detail below through examples.

[0060] Example

[0061] In this example, anthocyanins in the wine samples of the following experimental group and control group were determined.

[0062] White grape seed group (SW): Cabernet Sauvignon dry red wine was brewed with white grape seeds added before cold maceration. The brewing process and parameters for this group were identical to those for the CK group, except for the addition of white grape seeds. Specifically, the white grape seeds added to this group were Gewürztraminer grape seeds.

[0063] Control group (CK): Cabernet Sauvignon dry red wine produced by cold soaking process; no white grape seeds were added during the brewing process of this group of dry red wine.

[0064] At the same time, the white grape seed-added group and the control group were further divided into wine samples after the end of malolactic fermentation (EM) and after 4 months of bottle storage (BS).

[0065] In this example, the lightness L*, hue a*, and hue b* values ​​of the wine samples were measured using a CM-3700A spectrophotometer. The monomeric anthocyanins, polymeric anthocyanins, and non-anthocyanin phenols in each of the wine samples were measured after malolactic fermentation (EM) and after four months of bottle storage (BS) using HPLC-QqQ-MS. Aroma compounds in each of the wine samples were measured using a 7890 GC-5975 MS. The specific test results are as follows:

[0066] (1) Results of the color and hue of the wine in each experimental group:

[0067] according to Figure 1 The test results show that after adding white grape seeds, the L* value of the SW group was significantly lower than that of the CK group at the end of malolactic fermentation and after four months of bottle storage, while the a* and b* values ​​were significantly higher than those of the CK group. The L* value represents brightness, the a* value represents red hue, and the b* value represents yellow hue. This indicates that the addition of Gewürztraminer seeds significantly deepens the color of the wine and enhances the red hue, which is beneficial for the stability of the red hue during aging.

[0068] (2) Determination results of monomeric anthocyanins in the wine of each experimental group.

[0069] In this example, the contents of total monomeric anthocyanins, non-acylated anthocyanins, acetylated anthocyanins, and coumaroyl anthocyanins were specifically determined.

[0070] like Figure 2 As shown, after adding white grape seeds, the content of total monomeric anthocyanins, non-acylated anthocyanins, and acetylated anthocyanins in the wine was not significantly different from that in the control group, either at the end of malolactic fermentation or after four months of bottle storage. However, at the end of malolactic fermentation, the content of coumaroyl anthocyanins was significantly higher than that in the control group, indicating that the invention does not negatively affect the content of monomeric anthocyanins.

[0071] (3) Determination results of polymerized anthocyanins in the wine of each experimental group.

[0072] In this example, the content of total polymeric anthocyanins, polymeric anthocyanins directly or indirectly linked to flavan-3-ols, and polymers of anthocyanins and flavanols linked by ethyl / acetaldehyde bridges were specifically determined.

[0073] like Figure 3 As shown in the results, the addition of white grape seeds significantly increased the contents of total polymeric anthocyanins, polymeric anthocyanins directly or indirectly linked to flavan-3-ols, and ethyl / acetaldehyde-bridged anthocyanin and flavanol polymers in the wine at the end of malolactic fermentation and four months of bottle storage. This indicates that the technology of adding white grape seeds to participate in cold maceration and alcoholic fermentation is beneficial to the color stability of aged wine and has a positive effect on slowing down the oxidation and loss of polymeric pigments.

[0074] (4) Determination results of non-anthocyanin phenols in the wine of each experimental group.

[0075] In this example, for non-anthocyanin phenols, flavan-3-ols, flavonols, phenolic acids, and gallation rates were specifically measured.

[0076] like Figure 4 As shown, after adding white grape seeds, the phenolic acid and flavan-3-ol levels in the wine were significantly increased, while the flavonol content and gallation rate were significantly reduced compared to the control group after malolactic fermentation and four months of bottle storage. Flavonols contribute to bitterness, and a higher gallation rate indicates a stronger astringency in wine. Therefore, the white grape seed addition technology of the present invention can further reduce the astringency and bitterness of the wine, improving the smoothness of the wine.

[0077] (5) The results of the determination of the contents of total aroma substances, total esters, total alcohols, total aldehydes, and total isoprenoids in the wine of each experimental group, as well as the contents of most aroma components.

[0078] like Figure 5 As shown in the data, the addition of white grape seeds had no significant effect on the contents of total aroma substances, total esters, total alcohols, total aldehydes and total isoprenoids, as well as the contents of most aroma components, while significantly reduced the content of acid substances. This shows that the addition of white grape seeds to fermentation will not have a negative impact on the aroma substances of wine, and can also effectively reduce the negative sensory experience brought by acid substances.

[0079] The experimental results of the above examples show that the brewing method of the present invention, by adding white grape seeds to the fermentation tank before cold maceration, can significantly deepen the color of red wine, especially the red hue, and ensure good stability of the red hue of the red wine during the aging process.

[0080] There were no negative effects on anthocyanins and flavanols in red wine, indicating that the addition of white grape seeds did not substantially alter the structure of the resulting red wine. Furthermore, the addition of white grape seeds did not significantly negatively impact the aroma content of red wine.

[0081] Therefore, the present invention adds white grape seeds during the brewing process of red wine, which can effectively improve the color of the red wine and make it have good stability during the aging process, while having no negative impact on other sensory qualities of the red wine, such as flavor and aroma.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A brewing method for improving the color stability of red wine, characterized in that: After adding red grape raw materials into a fermentation tank, adding white grape seeds into the fermentation tank, and then cold soaking and fermenting are performed to obtain red wine; the mass ratio of the white grape seeds to the red grape raw materials is 3-7 g / kg; The brewing method comprises the following steps: S1. Destemming, screening, and crushing red grapes to obtain the red grape raw material; S2. Add the red grape raw material to the fermentation tank, and adjust the free SO2 to 50 mg / L; then add 20 mg / L of pectinase; S3, adding the collected white grape seeds into the fermentation tank; S4, cold soaking: the temperature of the cold soaking is 5-10°C; S5, alcohol fermentation: After the cold soaking is completed, the temperature is adjusted to 25°C, yeast is inoculated, and alcohol fermentation is initiated; during the alcohol fermentation period, the temperature is 22-25°C; S6, separating the skin and residue: squeezing the fermented liquor after the alcohol fermentation is completed, and then separating the skin and residue to obtain fermented wine; S7, performing malic acid-lactic acid fermentation: adding lactic acid bacteria to the fermented wine to initiate malic acid-lactic acid fermentation, wherein the temperature of the malic acid-lactic acid fermentation is 24-26° C.; S8. Free SO2 is adjusted to 35 mg / L, the malic acid-lactic acid fermentation is terminated, and the red wine is obtained.

2. A brewing method for improving the color stability of red wine according to claim 1, characterized in that: The white grape seeds are white grape seeds separated from the skin residue obtained by brewing dry white wine.

3. The brewing method for improving the color stability of red wine according to claim 1, characterized in that: The mass ratio of the white grape seeds to the red grape raw material is 5 g / kg.

4. The brewing method for improving the color stability of red wine according to claim 1, characterized in that: In step S4, the cold soaking time is 7 days.

5. A brewing method for improving the color stability of red wine according to claim 4, characterized in that: In step S5, the yeast inoculated is D254 yeast, and the inoculation amount is 200 mg / L.

6. A method for improving the color stability of red wine according to claim 4, characterized in that: In step S5, during the alcohol fermentation, the specific gravity of the fermentation liquid in the fermentation tank is measured. When the specific gravity drops below 1.000 and remains stable, the alcohol fermentation ends.

7. The brewing method for improving the color stability of red wine according to claim 4, characterized in that: In step S7, the amount of lactic acid bacteria added is 6 mg / L.

8. The brewing method for improving the color stability of red wine according to claim 4, characterized in that: In step S7, the malic acid-lactic acid fermentation takes 20 to 30 days.

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