Low-methanol fig wine brewing and clarifying method

Abstract

The invention belongs to the field of fruit processing, and particularly relates to a method for brewing and clarifying low-methanol fig wine. The method comprises the following steps: S1, preparing fig pulp: cleaning fresh or frozen figs, crushing and pulping the figs by using a double-channel pulping machine, adding potassium metabisulfite, rapidly heating for enzyme deactivation, and cooling after enzyme deactivation; s2, performing enzymolysis: adding pectin lyase into the fig pulp, and performing enzymolysis to obtain enzymatic hydrolysate; s3, centrifugal impurity removal: sequentially passing the enzymatic hydrolysate through a horizontal screw centrifuge and a butterfly separator to separate and remove impurities so as to obtain fig juice, and carrying out enzyme deactivation; s4, inoculating brewer's yeast to the fig normal juice, performing temperature-controlled fermentation to obtain fig raw wine, and performing standing for ageing; s5, comprehensive clarification: adding one or more of clarifying agents such as chitosan, bentonite, wine-brewing tannin and vegetable protein into the aged raw wine for comprehensive clarification, and filtering to obtain the clarified fig wine. According to the method, the content of methanol in the fig wine is reduced through enzyme deactivation in advance and enzymolysis with pectate lyase; and a clarifying agent is combined for clarification, so that the clarity of the fig wine is increased, the shelf life and shelf life of the fig wine are prolonged, and the quality and fragrance of the fig wine are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of fruit processing, and particularly relates to a method for preparing low-methanol clarified fig wine. Background Art

[0002] Fig is a perennial woody flowering plant of the genus Ficus in the family Moraceae of the order Rosaceae. The fruit has a sweet taste and has high nutritional and medicinal value. The content of dietary fiber, calcium, selenium, etc. is significantly higher than that of other fruits. It has good effects on preventing cancer, preventing cardiovascular diseases, delaying aging, enhancing digestive function, and promoting defecation.

[0003] Unlike fruits such as tomatoes and bananas which can be picked when green and eaten when ripe, figs can only be picked from the tree when they are edible. It is not obvious whether they are ripe, and they will age quickly after being picked due to many reasons such as seasonal weather. Also, during the picking process, cracks often appear on the round top of the fig, which easily attracts pests and diseases, causing the fruit to rot. These are the reasons why figs are not easy to store.

[0004] In view of the soft texture of figs, its deep processing and utilization are urgently needed. Fig wine is a low-alcohol fruit wine with health benefits obtained by fermenting figs with brewer's yeast.

[0005] CN108587834A discloses a method for preparing fig wine, which is characterized by comprising the following steps: adding 0.2-0.4wt% edible citric acid, water and food-grade pectinase to fig pulp for enzymolysis reaction; the amount of food-grade pectinase added is: adding 10,000-30,000 units of food-grade pectinase per kilogram of fig pulp; adding sugar to the enzymolyzed fig pulp to adjust the sugar content, inoculating a fermentation agent for fermentation. The fermentation agent used is dry yeast.

[0006] CN 113817565 A discloses a method for preparing fig wine, which is characterized by comprising the following steps: S1: preparation of fig pulp: washing and pulping fresh figs, and flash distillation pre-concentration to increase the sugar content of the fig pulp; S2: mixing the fig pulp with pectinase, potassium pyrosulfite and a sweetener, and enzymolyzing the mixture into an enzymolysis liquid; S3: inactivating the enzyme, inoculating lactic acid bacteria powder for anaerobic fermentation; S4: inoculating the fermented material with brewer's yeast for alcohol fermentation to obtain fig wine.

[0007] The above method uses pectinase hydrolysis to increase juice yield and clarity of fruit wine, but this method results in high methanol content in fruit wine, which is not good for human health. Another method uses pectinase hydrolysis and then concentration to remove methanol, although it reduces the methanol content, but the aroma substances evaporate with the methanol, resulting in insufficient aroma of fig wine and poor taste.

[0008] Therefore, it is necessary to improve the defects of the above two methods and invent a fig wine with low methanol content, excellent aroma, palatable taste, good clarity and stable quality during shelf life and a preparation method thereof. Summary of the invention

[0009] In order to solve the above technical problems, the present invention screened a specific and single-component pectinase - pectin lyase, which hydrolyzes fig juice, reduces the viscosity of the pulp, increases the juice yield, and controls the methanol content within a relatively low range; at the same time, one or more of chitosan, bentonite, plant protein, wine tannin, etc. are used to improve the clarity of the fruit wine, improve the stability of the fruit wine, and increase the shelf life of the fig wine.

[0010] The pectin lyase used in the present invention is specific and exclusive. Among all pectinases, only pectin lyase directly degrades pectin polymers through a β-elimination mechanism, resulting in the formation of 4,5-unsaturated oligogalacturonic acid, while other pectinases completely degrade pectin molecules in sequence. Moreover, pectin lyase degrades pectin without interfering with the ester group of the specific aroma of the juice, and will not cause the generation of toxic methanol. Therefore, there is no need to reduce methanol through concentration, thereby better retaining the aroma components of figs and significantly improving the quality of fig wine.

[0011] The method provided by the present invention comprises the following steps: S1: Preparation of fig pulp Fresh or frozen figs are sent to the workshop for processing. After cleaning, they are crushed by a double-pass pulper. During the crushing process, 0.05-0.2kg / T of potassium metabisulfite is added according to the amount of figs. After crushing, a tubular sterilizer is used to inactivate enzymes in the fig pulp at a temperature of 80-100℃ for 10-120 seconds. After the inactivation is completed, the temperature is lowered to 30-60℃ and the pulp is transferred to the enzymolysis tank.

[0012] The function of enzyme inactivation is, firstly, to inactivate the fig's own pectinase and, at the same time, to kill the bacteria caused by the opening of the fig.

[0013] S2: Enzymatic hydrolysis Pectin lyase is added to the fig pulp obtained in S1 in an amount of 0.1 kg / T to 0.9 kg / T. During the enzymolysis process, the temperature is controlled at 45-55° C. for 1-2 hours.

[0014] Pectin lyase can specifically decompose pectin and reduce the viscosity of fruit pulp, making it easier to separate it later. No methanol is produced during the enzymatic hydrolysis, which reduces the methanol content of fruit wine and ensures the safety of the final product.

[0015] S3: Centrifugal cleaning The enzymatic hydrolysate is sequentially passed through a horizontal screw centrifuge to remove large particles and a butterfly separator to separate fine impurities to obtain fig juice, and the added pectin lyase is inactivated in a tubular sterilizer at a temperature of 85-90° C. for 15-30 seconds. After the sterilization is completed, the temperature is lowered to 18-22° C. to obtain fig juice.

[0016] S4 fermentation and aging: add 0.5-3kg / T of naturally extracted tartaric acid to the fig juice obtained in S3, inoculate activated brewer's yeast, add 0.25-0.4kg / T of yeast, add 40-120kg / T of granulated sugar according to the alcohol content of the finished product after fermentation starts; control the temperature at 16-25℃ for fermentation, the fermentation cycle is 7-14 days, and the fermentation ends when the residual sugar drops to 4g / L. After fermentation ends, let it stand for aging, and the aging cycle is 3-12 months. During the aging period, separate the lees once every 1-3 months to prevent yeast autolysis from affecting the taste of fig wine.

[0017] Preferably, in the above step S4, the brewer's yeast is an active dry yeast, and dry white wine brewer's yeast is the best.

[0018] Preferably, in the above step S4, the best time to separate the lees is three times. After the fermentation is completed, most of the yeast is separated to ensure the taste of the fruit wine. After aging for one month, the lees are separated once. Before clarification, the lees are separated once in a tank transfer tank to facilitate the clarification of the fruit wine.

[0019] Adding naturally extracted tartaric acid can lower the pH of the original juice and reduce the risk of the original wine being infected by microorganisms during fermentation and aging, which leads to an increase in volatile acidity. The naturally extracted tartaric acid has a mild and non-irritating sourness, which improves the taste of fig wine.

[0020] S5: Comprehensive clarification After the aging is completed, one or more clarifiers such as chitosan, bentonite, plant protein, and wine tannin are added to the original wine for comprehensive clarification. After the gelling is completed, the wine is allowed to stand for 7-14 days and then filtered to obtain clarified fig wine.

[0021] Preferably, in the above step S5, the addition amount of chitosan is 0.1-0.5kg / T, the addition amount of bentonite is 0.8-2.0kg / T, the addition amount of plant protein is 0.2-1kg / T, and the addition amount of wine tannin is 0.05-0.5kg / T. The best effect is achieved when two or more clarifiers are used in combination.

[0022] Winemaking tannins can absorb excess protein in fruit wine and improve the stability of fruit wine, increase the tannin content of fig wine, make the fig wine fuller, and improve the typicality of fruit wine.

[0023] The beneficial effects of the present invention are: The invention reduces the viscosity of the fig pulp, improves the yield of the fig juice, reduces the pectin content, and improves the stability of the later product by inactivating enzymes in advance and selecting specific pectin lyase to enzymatically hydrolyze the fig pulp.

[0024] Adding naturally extracted tartaric acid in the early stage of fermentation and adding wine tannins during clarification can make the taste of fig wine softer and fuller, while also increasing the stability of the wine in the later stage.

[0025] By adding clarifiers such as chitosan, bentonite, plant protein, and wine tannins, the content of small molecular substances that are easily adsorbed and aggregated is reduced, thereby extending the shelf life of the fruit wine.

Claims

1. A method for brewing and clarifying low-methanol fig wine, comprising the following steps: S1: Preparation of fig pulp: fresh or frozen figs are washed, crushed and pulped with a double-pass pulping machine, potassium metabisulfite is added during the pulping process, the temperature is rapidly raised to inactivate the enzyme, and the temperature is lowered after the enzyme inactivation is completed; S2: Enzymatic hydrolysis: adding pectin lyase to fig pulp, mixing evenly, and performing enzymatic hydrolysis to obtain enzymatic hydrolyzate; S3: Centrifugal removal: The enzymatic hydrolysate is sequentially separated and removed of impurities by a horizontal screw centrifuge and a butterfly separator to obtain fig juice and inactivate the enzyme; S4: Fermentation. Aging: Inoculate the fig juice with brewer's yeast, and ferment it at a controlled temperature to obtain the fig wine. During the fermentation period, add white sugar to ensure that the alcohol content is within the required range. Ferment the wine to separate impurities and let it stand for aging. S5: Comprehensive clarification: After standing, one or more clarifiers such as chitosan, bentonite, plant protein, and wine tannin are added to the original wine for comprehensive clarification, and filtered to obtain clarified fig wine.

2. The method for brewing and clarifying low-methanol fig wine according to claim 1, characterized in that: In the S1, the amount of potassium pyrosulfite added is 0.05-0.2 kg / T, the enzyme inactivation temperature is 80-100°C, the time is 10-120S, and the cooling temperature is 30-60°C.

3. The method for brewing and clarifying low-methanol fig wine according to claim 1, characterized in that: In the S2, the enzyme preparation is pectin lyase, the addition amount is 0.1kg / T-0.9kg / T, the enzymolysis temperature is 45-55°C, and the time is 1-2 hours.

4. The method for brewing and clarifying low-methanol fig wine according to claim 1, characterized in that: In S3, the enzyme inactivation temperature is 85-90° C. and the time is 15-30 seconds.

5. The method for brewing and clarifying low-methanol fig wine according to claim 1, characterized in that: In S4, the amount of yeast added is 0.25-0.4 kg / T, the amount of white sugar added is 40-120 kg / T, the amount of naturally extracted tartaric acid added is 0.5-3 kg / T, the fermentation temperature is controlled at 16-25°C, the fermentation cycle is 7-14 days, the alcohol content at the end of fermentation is 6-14°C, and the residual sugar is 4 g / L. After fermentation, the lees are separated and left to age.

6. The method for brewing and clarifying low-methanol fig wine according to claim 1, characterized in that: The fermentation in S4 is static aging, and the aging period is 3-12 months. The lees are separated during the aging period, and the number of times is 1-3 times.

7. The method for brewing and clarifying low-methanol fig wine according to claim 1, characterized in that: The amount of chitosan added in S5 is 0.1-0.5 kg / T, the amount of bentonite added is 0.8-2.0 kg / T, and the amount of vegetable protein added is 0.2-1 kg / T. After adding the clarifier, the rest period is 7-12 days, and then filtering is performed.

8. The method for brewing and clarifying low-methanol fig wine according to claim 1, characterized in that: In S5, the winemaking tannin is preferably Youniangtan, and the addition amount is 0.05-0.5kg / T.