CN116121020A

CN116121020A - Medlar and pear compound fruit wine and production process thereof

Info

Publication number: CN116121020A
Application number: CN202310046578.XA
Authority: CN
Inventors: 王军节; 张怀予; 马进花; 马丽娅; 程龙帅; 王晓丹
Original assignee: North Minzu University
Current assignee: North Minzu University
Priority date: 2023-01-31
Filing date: 2023-01-31
Publication date: 2023-05-16

Abstract

The invention discloses medlar and pear compound fruit wine and a production process thereof, and particularly relates to the field of foods. The preparation method comprises the following raw materials: medlar, early crisp pear, yeast special for fruit wine, white granulated sugar, citric acid, pectase and glucose. The production process is as follows: pulping fructus Lycii and early crisp pear, and adding vitamin C into early crisp pear slurry; adding pectase into the mixed solution; adding white granulated sugar into the mixed solution, and adding citric acid; pasteurizing, cooling to room temperature, and inoculating yeast special for fruit wine; preparing glucose aqueous solution, activating active dry yeast with glucose aqueous solution, taking mixed fruit liquid, inoculating activated yeast into the mixed fruit liquid, inoculating into the prepared compound fruit juice, and stirring uniformly to perform main fermentation to obtain the compound fruit wine. The invention not only solves the problem of poor flavor of single fruit wine of medlar or pear, but also achieves the complementary characteristic of habit in traditional Chinese medicine, and can be used for making up the market blank of medlar and pear compound fruit wine, and simultaneously producing novel compound fruit wine with unique flavor and proper temperature and cool.

Description

Medlar and pear compound fruit wine and production process thereof

Technical Field

The invention relates to the technical field of foods, in particular to medlar and pear compound fruit wine and a production process thereof.

Background

The compound fruit wine has rich nutrition, high health care value, mellow fragrance, gorgeous color, good taste and unique flavor, has the refreshing effect of fruits, the mellow fragrance of wine and mild alcohol property, and has the effects of resisting oxidation, resisting aging, maintaining beauty, keeping young, preserving health, clearing heat, detoxifying and the like. At present, the composite fruit wine in the market is of various types, such as blackberry and hawthorn composite fermented fruit wine, coconut and cashew apple composite fruit wine, orange and pear juice composite wine, mango and papaya composite wine, hawthorn and grape composite wine, blueberry and grape composite fruit wine and the like, and most of the composite fruit wine is researched in the aspects of processing technology, production technology and the like. The fermentation process optimization and the dynamics and the research on the antioxidant activity of the medlar and pear compound fruit wine with the functions of nutrition and health care are not reported at home and abroad, but the fresh medlar and pear can be supplied all year round, is mainly rich in nutrition, and solves the problem of traditional Chinese medicine internal heat.

Disclosure of Invention

The invention aims to provide the medlar and pear compound fruit wine and the production process thereof, which not only solve the problem of poor flavor of medlar or pear single fruit wine, but also achieve the complementary characteristics of the habit in traditional Chinese medicine, and can be used for making up the market blank of medlar and pear compound fruit wine, and simultaneously produce novel compound fruit wine with unique flavor and proper temperature.

In order to achieve the above purpose, one technical scheme of the invention is as follows: a medlar pear compound fruit wine comprises the following raw materials: fructus Lycii, early crisp pear, yeast special for fruit wine of 0.40g/L, refined white sugar, citric acid, pectase, and glucose of 2% concentration accounting for 40% of total volume of fruit wine fermentation.

Another technical scheme of the invention is as follows: a production process of medlar pear compound fruit wine comprises the following steps:

s1, cleaning medlar and early crisp pears, pulping respectively, and adding 0.7g/kg vitamin C into early crisp pear slurry;

s2, mixing medlar slurry with early crisp pear slurry, and adding 80mg/L pectase into the mixed solution for enzymolysis, wherein the enzymolysis temperature is controlled at 40 ℃ and the enzymolysis time is 6 hours;

s3, adding white granulated sugar into the mixed solution after enzymolysis to adjust the sugar degree to 20%, and then adding citric acid to adjust the pH value to 4;

s4, pasteurizing the blended mixed solution, and cooling the mixed solution to room temperature to obtain a mixed fruit solution;

s5, preparing a glucose aqueous solution with the concentration of 2%, activating and standing 0.4g/L of active dry yeast with glucose water at 35 ℃ until the active dry yeast is naturally initiated until a large amount of bubbles are generated on the surface, taking a small amount of mixed fruit liquid prepared in the step S4, inoculating the activated yeast into the mixed fruit liquid to adapt to the environment of the compound fruit wine, finally inoculating the activated yeast into the prepared mixed fruit liquid, stirring uniformly, carrying out primary fermentation, and fermenting at the constant temperature of 25 ℃ for 7 days, thereby preparing the compound fruit wine.

Further, the sterilization treatment in step S4 is pasteurization at 65 ℃ for 10min.

Compared with the prior art, the beneficial effect of this scheme:

the medlar is considered as a food material with homology of medicine and food in the traditional Chinese medicine, is rich in at least 18 microelements and amino acids beneficial to human health, has nutritive value and has health care effect. Because the wolfberry fruit has thin peel, fresh and tender pulp and high moisture content, and can change color and taste after being placed for 3-7 days at normal temperature, the wolfberry fruit is easy to rot and even completely loses edible value, so that the wolfberry fruit products commonly seen in the market at present are mainly wolfberry fruit dry fruit products, other wolfberry fruit products, wolfberry fruit wine and other products. However, single fruit wine has limitations in terms of both its deep processing and its mouthfeel and nutritional value, such as: the medlar and pear compound fruit wine has the advantages that the medlar and pear compound fruit wine is deep in color, not bright, and not rich in aroma, some aroma components contained in the medlar are not well accepted by people, and the medlar and pear compound fruit wine is considered to be sweet in taste and flat in nature in traditional Chinese medicine, but cannot be eaten more every day, excessive eating can cause excessive liver fire and other reasons, the problem that the medlar or pear single fruit wine is poor in flavor is solved, the complementary characteristics of the traditional Chinese medicine habit are achieved, the market blank of the medlar and pear compound fruit wine can be made up, and meanwhile, the novel compound fruit wine with unique flavor and proper temperature is produced.

The composite fermentation medlar fruit wine has remarkable advantages and characteristics, can better infuse effective health-care components in two or more fresh fruits into wine through fermentation of microorganisms, is favorable for absorption and utilization of human bodies, has the functions of regulating immunity, resisting oxidation and aging, preventing diseases, reducing blood sugar, resisting tumors and osteoporosis and other functions, and has clear, transparent and full color, strong rich and rich fragrance, rich, mellow and lasting taste and typical unique appearance. Meanwhile, the fruit wine product has strong aroma and is rich in ethyl decanoate (fruit aroma), 2, 3-butanediol (astringency), ethyl octanoate (white land wine aroma), phenylethanol (flower aroma), glycerol (sweet taste) and the like. The early crisp pear used in the scheme has the advantages of cold nature, high water content, high sugar content, multiple organic acids, sweet taste, white pulp, delicious taste, fine texture, few stone cells, multiple fresh juice, sweet and delicious taste, and the like, so that the two characteristics of mild nature of the Chinese wolfberry and cold nature of the early crisp pear are combined to brew the composite fruit wine, the defect of a single fruit wine can be solved, the advantages of the single fruit wine are combined, and a foundation is laid for enriching the fruit wine and expanding the market space of the fruit wine.

The composite fruit wine has certain change rule of alcohol generation, consumption of matrix sugar and growth of saccharomycetes in the fermentation process, and index monitoring can provide reference value for the optimal drinking period of the fruit wine; the method for measuring the oxidation resistance of the compound fruit wine can provide theoretical basis for the health care effect and the nutritional value of the compound fruit wine. According to statistics, the annual output of the fruits in China is the first place in the world, but the deep processing level of the fruits in China is relatively backward, the fruits are especially rich in the fruit resources in China and the high-speed growing fruit wine consumer market are faced, and various fruits in the China are utilized according to local conditions to realize the diversified development of fruit wine varieties, so that the method has profound influence and significance.

Drawings

FIG. 1 is a flow chart of a production process of the medlar pear compound fruit wine of the invention;

FIG. 2 is a graph showing the effect of the amount of added wolfberry on the alcoholic strength of fruit wine in this example;

FIG. 3 is a graph showing the effect of yeast addition on fruit wine alcoholic strength in this example;

FIG. 4 is a graph showing the effect of pH on fruit wine accuracy in this example;

FIG. 5 is a graph showing the effect of fermentation time on fruit wine alcohol degree in this example;

FIG. 6 is a graph showing the effect of yeast addition and medlar addition on the response value of alcohol degree in this example;

FIG. 7 is a graph showing the effect of yeast addition and pH on the response to alcohol values in this example;

FIG. 8 is a graph showing the effect of the amount of wolfberry added and pH on the response surface value of alcoholicity in this example;

FIG. 9 is a graph showing the change of yeast count, alcohol content and reducing sugar mass concentration in the fermentation process of the compound fruit wine of the medlar and pear in the embodiment;

FIG. 10 is a graph showing the change in the number of yeasts with fermentation time in this example;

FIG. 11 is a graph showing the change in alcohol content with fermentation time in this example;

FIG. 12 is a graph showing the change in the amount of residual sugar with the fermentation time in this example;

FIG. 13 is a graph showing the change of total phenol content with fermentation time in this example;

FIG. 14 is a graph showing the change in DPPH radical scavenging rate with fermentation time in this example;

FIG. 15 is a graph showing the change in the reducing power with the fermentation time in this example.

Detailed Description

The invention is described in further detail below by way of specific embodiments:

examples:

as shown in figure 1, the medlar pear compound fruit wine comprises the following raw materials: fructus Lycii, early crisp pear, yeast special for fruit wine 0.40g/L, refined white sugar, citric acid, pectase 80mg/L, and glucose 2% concentration. In the embodiment, the wolfberry adopts Ningxia wolfberry fruit No. 5 fruits which are ground, and early crisp pear fruits are picked from cloisonne mountain farm in Gansu province; the special yeast for fruit wine is obtained from Angel Yeast Co., ltd; refined white granulated sugar, citric acid, ascorbic acid, potassium metabisulfite, pectase and glucose are all of commercial food grade. The total volume of the fruit wine fermentation in this example was 400mL.

The production process of the composite fruit wine comprises the following steps:

s1, cleaning medlar and early crisp pears, peeling and removing kernels of the early crisp pears, pulping medlar and early crisp pear pulp respectively, and adding 0.74g/kg of vitamin C into the early crisp pear pulp for color protection.

S2, mixing the medlar slurry with the early crisp pear slurry, and adding 80mg/L pectase into the mixed solution for enzymolysis, wherein the enzymolysis temperature is controlled at 40 ℃ and the enzymolysis time is 6 hours.

S3, adding white granulated sugar into the mixed solution after enzymolysis to adjust the sugar degree to 20% (preferably, dissolving the white granulated sugar by using a trace amount of water, avoiding the problem of uneven dissolution or difficult dissolution caused by agglomeration when the white granulated sugar is added into a fermentation bottle, cleaning the fermentation bottle before bottling and sterilizing by high-pressure steam), and then adding citric acid to adjust the pH value to 4 (the citric acid is prepared into a solution with a certain concentration for acid adjustment).

And S4, pasteurizing the blended mixed solution at 65 ℃ for 10min, and cooling to room temperature to obtain the mixed fruit solution.

S5, preparing a glucose aqueous solution with the concentration of 2%, activating and standing 0.4g/L of active dry yeast with glucose water at 35 ℃ until the active dry yeast is naturally initiated (about 30 min) until a large amount of bubbles are generated on the surface, taking a small amount of mixed fruit liquid prepared in the step S4, inoculating the activated yeast into the mixed fruit liquid to adapt to the environment of the compound fruit wine, inoculating the activated yeast into the prepared compound fruit juice, stirring uniformly, carrying out primary fermentation, and fermenting at the constant temperature of 25 ℃ for 7 days, thereby preparing the compound fruit wine.

1. Single factor investigation test of fermentation of medlar pear compound fruit wine:

and (3) respectively observing the influence of four factors of the addition amount of the medlar, the addition amount of the yeast, the initial pH of fermentation and the fermentation time in the medlar and pear compound fruit wine by single factor, and determining the technological parameters with better factors by taking the alcoholic strength as a main evaluation index and the sensory score as a reference index.

(1) Influence of the amount of added Lycium barbarum on the alcoholic strength of composite fruit wine

Testing fructus Lycii with five gradients of 20%,30%,40%,50% and 60%, respectively, adding 80mg/L pectase, adding white sugar to adjust sugar degree to 20%, adding citric acid to adjust pH to 4, pasteurizing at 65deg.C for 10min, standing at room temperature, naturally cooling to room temperature, inoculating yeast special for fruit wine with mass fraction of 0.4g/L, and fermenting at 25deg.C for 7 days. And (5) examining the alcoholicity and sensory evaluation quality index of the medlar pear compound fruit wine after main fermentation to determine the optimal raw material ratio.

(2) Influence of fermentation time on composite fruit wine alcoholic strength

Selecting a proportion of 40% of medlar, and setting the fermentation time as follows: 3d,5d,7d,9d,11 d. Adding 80mg/L pectase, adding white sugar to adjust sugar content to 20%, adding citric acid to adjust pH to 4, pasteurizing at 65deg.C for 10min, standing at room temperature, naturally cooling to room temperature, inoculating yeast special for fruit wine with mass fraction of 0.4g/L, and fermenting at 25deg.C. And (5) examining the alcoholicity and sensory evaluation quality index of the medlar pear compound fruit wine after main fermentation to determine the optimal fermentation temperature.

(3) Influence of Yeast addition on the alcoholic strength of composite fruit wine

The proportion of the medlar adding amount of 40% is selected, and the yeast adding amount is respectively set as follows: 0.3g/L,0.35g/L,0.4g/L,0.45g/L and 0.5g/L of pectase, white granulated sugar and citric acid are respectively added to adjust the sugar degree to 20%, pH value is adjusted to 4, pasteurization is carried out for 10min at 65 ℃, the mixture is placed at room temperature and naturally cooled to normal temperature, and the special yeast for fruit wine with the mass fraction gradient is inoculated, and is fermented for 7 days at constant temperature at 25 ℃. And (5) examining the alcoholicity and sensory evaluation quality index of the medlar pear compound fruit wine after main fermentation to determine the optimal yeast adding amount.

(4) Influence of initial pH on the alcoholic strength of composite fruit wine

The proportion of the medlar adding amount of 40% is selected, and the initial pH values are respectively set as follows: pH=3, 3.5,4,4.5,5, 80mg/L pectase, white granulated sugar, citric acid, pH to the gradient pH, pasteurizing at 65deg.C for 10min, naturally cooling to room temperature, inoculating yeast special for fruit wine with mass fraction of 0.4g/L, fermenting at 25deg.C for 7 days. And (5) examining the alcoholicity and sensory evaluation quality index of the medlar pear compound fruit wine after main fermentation to determine the optimal initial pH value.

2. And (3) optimizing the response surface of the composite fruit wine fermentation process:

the three factors of yeast addition amount, initial pH value and medlar addition amount are respectively selected through the single factor investigation test to carry out response surface optimization test (related parameters are shown in the following table 1), and the optimal fermentation process of the medlar pear compound fruit wine is determined.

TABLE 1 response surface test factors and horizontal design

Fruit wine sensory score:

sensory evaluation criteria for single post-fermentation mixed and composite fermented fruit wine were formulated according to the relevant scoring criteria as shown in table 2 below, and were evaluated by a panel of 8 persons, and the single post-fermentation mixed and composite fermented fruit wine was comprehensively scored in terms of color, aroma, taste and typical properties, and then compared with the two fermentations to obtain the optimal fermentation process for subsequent fermentation kinetics and antioxidant activity determination.

Table 2 fruit wine scoring criteria

And (3) physical and chemical index measurement of the fruit wine:

measuring the alcohol content: distillation process

Determination of soluble solids: hand-held refractometer method

Determination of total sugar: filin reagent method

Measuring the pH value: PH meter method

The above measurement methods are all measured according to GB/T15038-2006 general analysis method for grape wine and fruit wine.

Fermentation dynamics model establishment and related index determination:

the change rules of the concentration of saccharomycetes, the alcohol degree and the mass concentration of reducing sugar in the fermentation process of the medlar pear compound fruit wine are measured, and the method is as follows:

(1) The concentration of yeast was calculated using a hemocytometer.

(2) The mass concentration of the reducing sugar is determined by adopting a Filin reagent titration method according to GB/T15038-2006 general analysis method for wine and fruit wine.

(3) The alcoholicity was determined according to the method in 3.2.5.

Determination of antioxidant activity of composite fruit wine:

(1) And (3) determining total phenols in the medlar pear compound fruit wine, and determining the content of phenols by adopting a Folin-Ciocalteu method.

Drawing a gallic acid standard curve, preparing a sample solution, and measuring the sample solution.

(2) The antioxidation effect of the medlar pear compound fruit wine selects two indexes of DPPH free radical and reduction capability for research.

(3) A test method for removing DPPH free radical from fructus Lycii and fructus Pyri compound fruit wine is provided.

(4) A method for testing the reduction capability of compound fruit wine of fructus Lycii and pear.

3. Single factor analysis of composite fermented fruit wine of wolfberry fruit and pear

(1) Influence of the amount of added Lycium barbarum on the alcoholic strength of fruit wine

Under the premise that the total volume of each bottle of the fermentation of the medlar and pear compound fruit wine is 400ml and the total volume of medlar is unchanged, medlar with different percentages of 20%,30%,40%,50% and 60% is added according to a single-factor test design, and the rest volume is added into pear juice according to a proportion. Other conditions of fermentation are set in sequence according to experimental design to explore the influence of different medlar adding amounts on the alcoholic strength in the fermentation process of medlar and pear compound fruit wine. As shown in FIG. 2, the alcohol contents of the composite fruit wine produced during the fermentation process are different from each other, and the change is in a single peak trend, so that it can be seen that the alcohol content produced when the added amount of the medlar is 40% is 12.30% vol at the highest, and the alcohol content when the added amount of the medlar is 50% is the smallest, so that the optimal medlar added amount when the added amount of the medlar is 40% can be obtained.

(2) Influence of Yeast addition on fruit wine alcohol degree

The gradient of the yeast addition amount set by the medlar pear compound fruit wine in the single factor investigation test design is respectively as follows: the influence of the yeast addition amount on the alcoholic strength of the medlar pear compound fruit wine in the fermentation process is studied by 0.3g/L,0.35g/L,0.4g/L,0.45g/L and 0.5 g/L. As shown in FIG. 3, it can be seen that the alcohol contents generated during the fermentation process of the compound fruit wine of medlar and pear by the different yeast addition amounts are different, the whole compound fruit wine has a single peak trend, the alcohol content is minimum by 10.13 percent vol when the yeast addition amount is 0.45g/L, and the alcohol content generated when the yeast addition amount is 0.40g/L is maximum by 11.9 percent vol, so that the optimal yeast addition amount of the compound fruit wine of medlar and pear can be obtained when the yeast addition amount is 0.40 g/L.

(3) Influence of pH value on fruit wine alcohol degree

The gradient of the set pH value of the medlar pear compound fruit wine in the single factor investigation test design is as follows: ph= 3,3.5,4,4.5,5 to investigate the effect of pH on the alcoholic strength of the medlar pear compound fruit wine during fermentation. As can be seen from FIG. 4, the pH values with different gradients are different in the fermentation process of the compound fruit wine of the Chinese wolfberry and the pear, the alcohol degree is changed in a unimodal manner, the alcohol degree is firstly in a linear increasing trend along with the increase of pH, the alcohol degree is maximum when the pH value is 4.0, and then in a decreasing trend, so that the initial pH value which is the optimal fermentation of the compound fruit wine of the Chinese wolfberry and the pear when the initial pH value of the fermentation is 4.0 can be obtained.

(4) Influence of fermentation time on fruit wine alcohol degree

Gradient of fermentation time of the medlar and pear compound fruit wine in single factor investigation test design is respectively: 3d,5d,7d,9d and 11d to explore the response of fermentation time to the alcoholic strength of the medlar pear compound fruit wine in the fermentation process. As shown in figure 5, the alcoholic strength of the medlar and pear compound fruit wine is trapezoidal in shape in the fermentation process along with the extension of the fermentation time, the alcoholic strength is continuously increased in the early stage of fermentation, the highest alcoholic strength reaches 11.8% vol at the 7 th day of fermentation, and the fermentation after 7 days is stable. Therefore, the optimal fermentation time for the medlar pear compound fruit wine on the 7 th fermentation day can be obtained.

The fermentation process of the medlar pear compound fruit wine is optimized by the response surface:

(1) Statistical analysis of response surface optimization test results

And according to the analysis of the single-factor test result, selecting the optimal test value ranges of three factors, namely medlar addition amount, yeast inoculation amount and pH value, and entering a response surface optimization test. Optimum design according to the factor level of Table 1, three-factor three-level test was designed to test the alcohol degree as the response value, and the test combination mode and test result of each factor are shown in tables 3 and 4

TABLE 3 response surface test design and result analysis

TABLE 4 regression model analysis of variance

Table 4.2 (subsequent)

According to the test result of analysis of variance on fermentation of the medlar pear compound fruit wine, the significance of the influence of each variable on the response value in the regression equation is judged by using F test, and the smaller the probability p value is, the higher the significance degree is.

Obtaining a quadratic regression fit equation about the alcoholic strength of the medlar pear compound fruit wine by a response surface analysis method: alcohol content (% Vol) =0.32-0.12A-0.25b+0.38c-0.23ab+0.038ac-0.63 BC-1.43A2-0.74B2-0.40 xc 2 (wherein a-yeast addition amount, B-medlar addition amount, C-pH value).

As shown in the analysis of variance results of the regression equation model, the F value of the model is 25.53, p=0.0002 <0.05, the model is obvious, the F value of the mismatch item is 2.06, the P value is 0.2486>0.01, the result is not obvious, the interaction of the A-yeast additive and the B-medlar additive is shown in the model, and the interaction of the C-pH value is a obvious factor, so that the regression equation has better fitting and credibility in a regression area in the medlar pear compound fruit wine in the test, the test error is smaller, and a relatively good linear relation between the independent variables and the response values of all factors is provided, so that the model can be said to be used for carrying out good prediction on the technological study of the medlar pear compound fruit wine, and can be used for theoretical speculation of the medlar pear compound fruit wine technological optimization test. Namely, each factor during fermentation is optimally as follows: the addition amount of yeast is 0.4g/L, the addition amount of medlar is 40%, and the initial pH value of fermentation is 4.

(2) Fermentation prediction model establishment and verification

The following three response surface diagrams and the shape of the contour line are obtained through analysis of Design-expert 8.0.6 software in the test, and the influence of interaction among factors on response values can be seen from fig. 6-8, and the shape of the contour line reflects the strength of interaction benefits.

Verification test

The fermentation condition of the response surface, preferably medlar and pear compound fruit wine, is subjected to 3 times of parallel tests to verify the reliability and stability of the medlar and pear compound fruit wine, and the verification result shows that the degree of difference between the result obtained by the tests and the theoretical predicted value is within an allowable range, so that the test data has reliability.

(3) Fruit wine quality index analysis

Four physicochemical indexes of total sugar, pH value, alcohol degree and soluble solid are used as evaluation indexes by using the optimized medlar pear compound fruit wine, and the results are shown in table 5.

Table 5 physicochemical index of fructus Lycii and fructus Pyri composite fruit wine

Table 6 organoleptic scores of two fermentation processes

Two fermentation processes can be seen from table 6: the sensory scores of the compound fermentation obtained by the compound fermentation method and the single-fermentation after-mixing through sensory evaluation are generally higher than those of the compound fermentation after-mixing, which indicates that the fruit wine obtained by the compound fermentation of the technical scheme is superior to the fruit wine obtained by the single-fermentation after-mixing in four aspects of color, aroma, taste and typical property, so that the fermentation process research and the fermentation dynamics and the measurement of the antioxidant activity of the medlar pear compound fruit wine are carried out by the production process of the technical scheme.

4. Constructing a fermentation kinetics model of the medlar pear compound fruit wine:

yeast number, reducing sugar matrix and product alcohol change in fermentation process of medlar pear compound fruit wine

In the process of fermenting the composite fruit wine by utilizing the yeast special for the fruit wine, saccharomycetes are main fermentation microorganisms in the fermentation of the fruit juice, and reducing sugar in the fruit juice system is utilized to maintain the self-growth requirement and metabolize to generate alcohol. The main component changes of the fermentation process are shown in FIG. 9.

The graph 9 shows that the growth rule of the yeast special for the Angel fruit wine is typical, the fermentation stages are clear, the yeast grows slowly in the initial fermentation stage of the medlar pear compound fruit wine, namely before 24 hours, the slow growth in the stage is caused by the fact that the yeast just enters the compound fruit juice and the self metabolism system of the complex environment is slowly adapting to the fermentation environment, the yeast synthesizes substances required by self growth by utilizing the nutrient substances of the compound fruit juice system, and the result is reflected in that the quantity of the yeast cells increases slowly; after the fruit wine is fermented for 24 hours, the growth of the saccharomycetes enters a logarithmic growth phase, and after a short environmental adaptation phase, the reducing sugar and other components in the compound fruit juice are rapidly consumed by the saccharomycetes, and the number of the saccharomycetes is exponentially increased; after 84 hours of fermentation, the reducing sugar in the compound juice is consumed relatively quickly, and alcohol produced by metabolism of saccharomycetes is accumulated continuously to a certain extent to inhibit the growth of the thalli, so that the saccharomycetes enter a growth stabilizing period, and the quantity of the thalli is up to 10.03X107 cfu/mL. Meanwhile, the speed of alcohol production by saccharomycetes through decomposition and metabolism of reducing sugar in the medlar pear compound fruit wine also shows a rapid increase trend along with 24 hours later when the saccharomycetes enter an exponential growth phase; after 84 hours, the saccharomycetes begin to grow slowly, the increase of the alcoholic strength is also slowed down, and the alcoholic strength of the medlar and pear compound fruit wine reaches 12.1 percent vol at the highest when the fermentation is carried out for 168 hours. For the reducing sugar content of the fermentation system, the change of the reducing sugar content is changed in an opposite rule with the saccharomycetes, namely the reducing sugar content gradually decreases along with the continuous increase of the number of the saccharomycetes, and the reducing sugar in the fermentation system is gradually catabolized to generate alcohol. The residual sugar amount of the fermentation system is quickly reduced before 84 hours, the yeast amount and the alcohol degree are slowly increased after 84 hours, the residual sugar amount is slowly reduced at the moment, and the residual sugar amount is reduced to 1.8g/L when the fermentation is carried out for 168 hours, so that the fermentation of the composite fruit wine is finished. The analysis of the test data and the curve chart shows that the reduction sugar residue in the fermentation system of the medlar and pear compound fruit wine has good correlation with the growth rule of saccharomycetes.

Medlar and pear compound fruit wine fermentation kinetics model

The fermentation kinetics of the fruit wine is mainly to explore the relation of the growth of yeast thallus, the production of products such as alcohol and the like and the consumption of reducing sugar matrix along with the change of fermentation time in the fermentation process of the fruit wine. The experiment adopts origin8.0 software to carry out nonlinear fitting on the test data of the change of the yeast number, the product alcohol and the residual reducing sugar in the fermentation process of the medlar pear compound fruit wine, establishes a fermentation dynamics model, has further understanding on the fermentation process of the medlar pear compound fruit wine, and provides a theoretical basis for a standardized production process.

(1) Yeast number growth dynamics model

The number of saccharomycetes in the fermentation process of the medlar pear compound fruit wine is subjected to nonlinear fitting by using a Logistic classical model, and the fitting degree R2 of the model is 0.996 shown in fig. 10, so that the fitting effect is good, and the model can be used for describing the dynamic growth process of the number of saccharomycetes in the fermentation process of the medlar pear compound fruit wine.

(2) Alcohol degree dynamics model

As shown in FIG. 11, the alcoholic strength dynamic model of the medlar pear compound fruit wine in the fermentation process also selects a classical Logistic model to carry out nonlinear fitting on the change, and the result shows that the fitting degree R2 is 0.998, and the fitting effect is good. The model can better describe the alcohol degree change process in the fermentation process of the medlar and pear compound fruit wine.

(3) Residual sugar quantity dynamics model

The main function of reducing sugar in the fermentation process of the fruit wine is to serve as an energy substance to provide nutrient substances required by the growth of saccharomycetes, and some substances produced by mechanism metabolism in the fermentation process can properly improve the taste of the fruit wine. According to an empirical model, doseResp is selected to fit the compound fruit wine, a fitting curve is obtained, as shown in figure 12, the fitting degree R2 is 0.998, the fitting effect is good, and the model can better reflect the dynamic change of the residual sugar amount in the fermentation process of the compound fruit wine of the Chinese wolfberry and the pear.

Dynamic analysis of antioxidation activity of medlar and pear compound fermentation fruit wine

Total phenol content change in fermentation process of medlar pear compound fruit wine

The gallic acid standard curve equation is y=4.6393x+0.0094 (r2=0.9949). Based on this equation and the absorbance measured by the test, the total phenol content can be calculated. As can be seen from FIG. 13, the total phenol content of the medlar pear compound fruit wine is increased before 72 hours of fermentation, because the juice yield of the fruit wine is increased by complex chemical changes in a fast yeast growth system in the fermentation process at the stage, and the total phenol content is reduced after 72 hours of fermentation, and is reduced slowly after 120 hours, the main reason of the process is that enzymes are generated in the mechanism metabolism process of the yeast and medlar original flora, so that macromolecular substances such as polyphenol are decomposed by enzymes, and the phenol content is reduced.

DPPH free radical scavenging rate change in fermentation process of medlar pear compound fruit wine

As can be seen from fig. 14, the overall change of the DPPH radical scavenging rate shows a tendency of slightly rising and then slightly falling, which is similar to the trend of the change of the total phenol content of the compound fruit wine of the medlar and pear in the fermentation process, the DPPH radical scavenging rate shows a slow rising in the middle period before the compound fruit wine is fermented, the fermentation rate of the compound fruit wine is also faster along with the rapid growth of saccharomycetes in the stage, juice is discharged greatly, and the content of antioxidant substances is increased. After 84 hours, the DPPH free radical scavenging rate is gradually decreased, which is not very different from the DPPH free radical scavenging rate of normal juice, namely fermentation time of 0 hours, because partial oxidation resistance substances are unstable in nature and enzymes generated in the fermentation process decompose macromolecular substances such as phenols, so that oxidation resistance is reduced, and the DPPH free radical scavenging rate is also reduced.

Reduction capability change in fermentation process of medlar pear compound fruit wine

From fig. 15, it is apparent that, as the trend of the curve proceeds, the reduction power of the compound fruit wine of fructus Lycii pear gradually decreases before 72h, probably because the oxidation resistance of the compound fruit wine is gradually decreased and the reduction power of the compound fruit wine is gradually increased during the fermentation period due to the complex chemical change of the oxidation resistance substances generated by the mechanism system along with the growth of yeast, which is generally shown as the total oxidation resistance is greater than the reduction power, so that the reduction power is reduced during the period, and then the enzyme generated during the fermentation period affects the oxidation resistance mechanism of the active ingredient, the oxidation resistance is reduced and the reduction power is gradually increased along with the extension of the fermentation period, namely after 72h, and the reduction power is enhanced but is weaker than the compound fruit juice of fructus Lycii pear.

The fermentation dynamics model is established for the yeast number, the product alcohol and the residual reducing sugar in the fermentation process of the fruit wine, so that the fermentation process of the medlar and pear compound fruit wine is further known, and a theoretical basis is provided for a standardized production process.

Aroma component analysis of medlar and pear composite fermentation fruit wine

Analysis of aroma components in medium-term aroma fermentation of medlar pear compound fruit wine

53 volatile substances are analyzed in the middle fermentation period through detection. 13 alcohols, 8 acids, 15 esters, 2 aldehydes, 3 thin alcohols, 5 ketones and 7 other substances. Wherein the alcohol accounts for 53% or so, and the isoamyl alcohol content is the highest; the ethyl octanoate and ethyl decanoate content in the esters was about 51.92% of the total ester content; the organic acid has a relatively high acetic acid content of about 26.72% of all acids. The main aroma components in the middle stage of fermentation are as follows: ethyl octanoate (brandy flavor), ethyl decanoate (fruit flavor), phenethyl alcohol (aroma), hexadecanoic acid (flower flavor), 2, 3-butanediol (astringency), and the like.

TABLE 7 analysis results of aroma components of fermented 3d composite fruit wine

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Analysis of aroma components of medlar pear compound fruit wine in aroma fermentation later stage

44 volatile substances of the medlar and pear compound fruit wine are identified at the later period of fermentation. Alcohols 12, acids 4, esters 21, aldehydes 2, ketones 4, and other substances 3. Wherein the alcohol substance accounts for the most, and the isoamyl alcohol content is the most remarkable; the ethyl palmitate, ethyl decanoate and ethyl octanoate content in the esters is 57.57 percent of the total esters content; the organic acid has a relatively high acetic acid content of about 75.51% of all acids. The main aroma components in the later fermentation stage are as follows: glycerol (sweet), 2, 3-butanediol (astringent), ethyl decanoate (fruit flavor), ethyl octanoate (brandy flavor), phenylethanol (flower flavor), etc.

TABLE 8 analysis results of aroma components of fermented 6d composite fruit wine

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As can be seen from tables 7 and 8, the ester compound has fruity smell and unique aromatic flavor with an increase in the ester substance ratio upon prolonged fermentation time. The typical fruit wine aroma substances in the table, such as ethyl octanoate (brandy aroma), ethyl decanoate (fruit aroma), and 2, 3-butanediol (astringency), increase with the fermentation time.

The foregoing is merely exemplary of the present invention and the details of construction and/or the general knowledge of the structures and/or characteristics of the present invention as it is known in the art will not be described in any detail herein. It should be noted that modifications and improvements can be made by those skilled in the art without departing from the structure of the present invention, and these should also be considered as the scope of the present invention, which does not affect the effect of the implementation of the present invention and the utility of the patent. The protection scope of the present application shall be subject to the content of the claims, and the description of the specific embodiments and the like in the specification can be used for explaining the content of the claims.

Claims

1. A medlar pear compound fruit wine is characterized in that: the preparation method comprises the following raw materials: fructus Lycii, early crisp pear, yeast special for 0.40g/L fruit wine, refined white sugar, citric acid, pectase, and glucose with concentration of 2% accounting for 40% of total volume of fruit wine fermentation.

2. A production process of medlar pear compound fruit wine is characterized in that: the method comprises the following steps:

s5, preparing a glucose aqueous solution with the concentration of 2%, activating and standing 0.4g/L of active dry yeast with glucose water at 35 ℃ to perform natural fermentation until a large amount of bubbles are generated on the surface, namely, the activation is completed, taking a small amount of mixed fruit liquid prepared in the step S4, inoculating the activated yeast into the mixed fruit liquid to adapt to the environment of the compound fruit wine, finally inoculating the activated yeast into the prepared mixed fruit liquid, uniformly stirring, performing main fermentation, and performing constant-temperature fermentation at 25 ℃ for 7 days, thereby preparing the compound fruit wine.

3. The process for producing the medlar pear compound fruit wine according to claim 2, which is characterized in that: the sterilization treatment in step S4 is pasteurization at 65 ℃ for 10min.