Method for increasing content of anthocyanin in concentrated grape juice by using enzyme

Abstract

The invention relates to the field of food processing, in particular to a method for increasing the content of anthocyanin in concentrated grape juice through enzyme. According to the Rapidase Smart Clear Plus enzyme and / or the Pectinex Ultra Color enzyme provided by the invention, the improvement of the extraction rate of total anthocyanin and key monomer anthocyanin in the concentrated grape juice can be effectively realized, so that the quality of the concentrated grape juice is improved.

Description

Technical Field

[0001] The invention relates to the field of food processing, in particular to a method for increasing the content of anthocyanin in concentrated grape juice by utilizing enzymes. Background Art

[0002] Concentrated grape juice is an important deep-processing product of grapes. After concentration, it can not only extend the shelf life, but also retain the original nutrients to a large extent. It can be used to make grape juice and grape juice beverages, as well as wine. The important active ingredient in concentrated grape juice is anthocyanin, which is a natural colored flavonoid phenolic compound formed by the combination of anthocyanidins and various monosaccharides in plants to form glycosides. As the main coloring substance of grapes, anthocyanins give grapes and their products bright colors. Changes in their content not only affect the color of concentrated grape juice, but also affect the functional characteristics of the product.

[0003] However, anthocyanins contain multiple phenolic hydroxyl groups, have poor structural stability, and are easily decomposed by temperature, pH, light, etc. Therefore, in the traditional processing process, grape juice is prepared using conventional crushing-enzymatic hydrolysis-pressing-ultrafiltration-concentration steps, which lacks control and optimization of key processing processes, resulting in a large loss of anthocyanins in grape juice. It is not clear how to increase the anthocyanin content of concentrated grape juice during processing, key control points in the processing engineering are missing, and the monomer components that have a greater impact on total anthocyanins are unclear. These problems restrict the improvement of the quality of concentrated grape juice.

[0004] Therefore, it is necessary to improve the existing processing technology of concentrated grape juice and increase the content of anthocyanins in the concentrated grape juice. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for increasing the content of anthocyanins in concentrated grape juice. Firstly, the factors significantly affecting the content of anthocyanins are analyzed and studied, and the pH differential method and high performance liquid chromatography-mass spectrometry are used for detection in the processing of concentrated grape juice to determine that the enzymatic hydrolysis section of the pulp is the key control point for the change of the content of anthocyanins; then, on this basis, a specific pulp enzyme is added to the crushed grapes to increase the content of anthocyanins in the final product concentrated grape juice, and the added enzyme is specifically Rapidase Smart Clear Plus enzyme or Pectinex Ultra Color enzyme.

[0006] The changes in the content of total anthocyanins and monomeric anthocyanins during grape juice processing were detected using the pH differential method and high performance liquid chromatography-mass spectrometry, respectively, to clarify the changing patterns of total anthocyanins and monomeric anthocyanins throughout the processing process and the key control points affecting the dissolution of anthocyanins. On this basis, the process was optimized, the effects of different enzymes on total anthocyanins, monomeric anthocyanins and color values ​​(L value, a* value, b* value) were determined, the monomeric anthocyanins that had the greatest impact on total anthocyanins were identified, and the optimal enzyme was comprehensively screened.

[0007] The inventors have found through experiments that the key control point for the anthocyanin content in concentrated grape juice is the enzymatic hydrolysis process.

[0008] In the processing of concentrated grape juice, Rapidase Smart Clear Plus enzyme and / or Pectinex Ultra Color enzyme are mainly used to increase the anthocyanin content. The specific method is to add Rapidase Smart Clear Plus enzyme and / or Pectinex Ultra Color enzyme to the crushed grapes for enzymatic hydrolysis, and then press, sterilize, juice enzymatic hydrolysis, ultrafilter and concentrate to obtain concentrated grape juice with high anthocyanin content.

[0009] Preferably, the anthocyanins include total anthocyanins and at least one of the following monomeric anthocyanins: malvidin-3-O-glucoside, delphinidin-3-O-glucoside, and cyanidin-3-O-glucoside.

[0010] Preferably, based on the weight of the crushed grapes, 0.01% RapidaseSmart Clear Plus enzyme or 0.01% Pectinex Ultra Color enzyme is added to the crushed grapes, and enzymolysis is performed at 40-50° C. for 0.3-0.8 h.

[0011] The technical solution of the present invention is:

[0012] A method for increasing the anthocyanin content in concentrated grape juice using Rapidase Smart Clear Plus enzyme and / or Pectinex Ultra Color enzyme comprises the following steps:

[0013] (1) Select, wash and crush grapes;

[0014] (2) adding fruit pulp to the crushed grapes for enzymatic hydrolysis; the enzyme used is Rapidase Smart Clear Plus enzyme or Pectinex Ultra Color enzyme, the amount of enzyme added is 0.01% based on the weight of the grapes, the enzymatic hydrolysis temperature is 40-50° C., and the enzymatic hydrolysis time is 0.3-0.8 h;

[0015] (3) pressing and pasteurizing at 90-98° C. for 25-35 seconds to obtain juice;

[0016] (4) The juice is enzymatically hydrolyzed, ultrafiltered, and concentrated to obtain a finished concentrated grape juice.

[0017] Preferably, the grapes in (1) are summer black grapes.

[0018] Preferably, in (4), the juice is enzymatically hydrolyzed using 0.02% by mass of pectinase Smart Clear and 0.01% by mass of amylase GA 3X at 45-60° C. for 0.3-0.8 h.

[0019] Preferably, in (4), the molecular weight cutoff of the filter membrane used for ultrafiltration is 10000Da, and the pressure is ≤1.5MPa.

[0020] Preferably, in (4), the concentration condition is to transfer the ultrafiltered grape juice to a rotary evaporator and rotary evaporate at 60°C and 65 rpm / min until the sugar content of the grape juice is 40° Brix.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention detects and analyzes the changes in total anthocyanins and color values ​​(L value, a* value, b* value) in different processing stages of concentrated grape juice, and clarifies that the enzymatic hydrolysis stage of the pulp has a significant impact on the anthocyanin content. Therefore, the enzymes in this stage are screened and compared, and finally a suitable enzyme is selected to enzymatically hydrolyze the crushed grapes, and then through squeezing, sterilization, juice enzymatic hydrolysis, ultrafiltration and concentration, the anthocyanin content and the color quality of the grape juice in the final product are improved;

[0023] (2) Through the analysis of the content of monomer anthocyanins during the processing, it was determined that malvidin-3-O-glucoside, delphinidin-3-O-glucoside, and cyanidin-3-O-glucoside were the key monomer substances that affected the changes in the total anthocyanin content during the processing. By measuring the effects of different enzymes on anthocyanin monomers, SCP enzyme was screened as the key enzyme for extracting anthocyanins in the concentrated grape juice processing, which is of great significance to improving the quality of grape juice during the processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Appearance characteristics of different stages in the processing of concentrated grape juice;

[0025] Figure 2 Changes of total anthocyanin content in different stages of concentrated grape juice;

[0026] Figure 3Growth ratio of total anthocyanin content in different stages of concentrated grape juice;

[0027] Figure 4 Changes in color values ​​(L value, a* value, b* value) of concentrated grape juice samples at different stages;

[0028] Figure 5 Correlation between monomer anthocyanins and color values ​​in different stages of concentrated grape juice;

[0029] Figure 6 Total anthocyanin content of different enzymatic hydrolyses;

[0030] Figure 7 The content of monomer anthocyanin in delphinidin-3-O-glucoside after different enzymatic hydrolysis;

[0031] Figure 8 The content of monomer anthocyanin in malvidin-3-O-glucoside hydrolyzed by different enzymes;

[0032] Fig. 9 The content of monomer anthocyanin in cyanidin-3-O-glucoside hydrolyzed by different enzymes. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in conjunction with specific embodiments. However, the scope of the present invention is not limited to the following embodiments.

[0034] The enzymes used in this application are from the following manufacturers:

[0035] Table 1 Enzyme names and manufacturers

[0036]

[0037] Example 1

[0038] 1.1 A method for increasing the anthocyanin content in the processing of concentrated grape juice, comprising the following steps:

[0039] (1) Select, wash and crush summer black grapes;

[0040] (2) adding fruit pulp to the crushed grapes for enzymatic hydrolysis; the enzyme used for enzymatic hydrolysis is Pectinex Ultra Color, the amount of enzyme added is 0.01% of the weight of the grapes, and the enzymatic hydrolysis is carried out at 45° C. for 0.5 h;

[0041] (3) pressing and pasteurizing at 95°C for 30 seconds to obtain juice;

[0042] (4) The juice was enzymatically hydrolyzed using 0.02% by weight of Smart Clear pectinase and 0.01% by weight of GA 3X amylase. The juice after enzymatic hydrolysis was ultrafiltered using a filter membrane with a molecular weight cutoff of 10,000 Da (model: UFOLO 98928) at a pressure of ≤1.5 MPa, and then concentrated to 40° Brix by rotary evaporation at 60° C. and 65 rpm / min to obtain a finished concentrated grape juice, and the anthocyanin content thereof was detected.

[0043] 1.2 The detection method of anthocyanins is as follows:

[0044] (1) Total anthocyanins were measured by pH differential method: 1.0 mL of crushed, squeezed, pasteurized, enzymatically hydrolyzed, ultrafiltered, and concentrated (after dilution) samples were measured in test tubes. Three parallel experiments were performed for each group of samples. 4.0 mL of pH 1.0 potassium chloride buffer and pH 4.5 sodium acetate buffer were added, respectively, and the mixture was shaken and mixed. The mixture was placed at room temperature and away from light for 50 minutes to allow the solution to reach dynamic equilibrium. Distilled water was used as a control, and the absorbance of the two samples was measured by UV spectrophotometer at wavelengths of 510 nm and 700 nm. Each sample was measured three times in parallel.

[0045] Calculation formula for total anthocyanins:

[0046] Total anthocyanins (mg / L) = (A×MW×DF×1000) / (ε×L)

[0047] A=(A510-A700)pH=1.0-(A510-A700)pH=4.5

[0048] Wherein: MW is the molecular weight of cyanidin-3-glucoside, 449.2 g / mol; DF is the dilution factor; ε is the extinction coefficient of cyanidin-3-O-glucoside, 26900 L / mol×cm; L is the optical path length.

[0049] (2) Detection of monomeric anthocyanins using high performance liquid chromatography:

[0050] The chromatographic conditions are:

[0051] Chromatographic column: C18 column, 250mm×4.6mm×5μm; mobile phase A is 1% formic acid aqueous solution, mobile phase B is 1% formic acid acetonitrile solution; detection wavelength: 530nm; column temperature: 35℃; injection volume: 20μL;

[0052] The gradient elution conditions are shown in Table 2:

[0053] Table 2 Gradient elution conditions

[0054]

[0055] Example 2

[0056] A method for increasing anthocyanin content in a concentrated grape juice processing process comprises the following steps:

[0057] (1) Select, wash and crush summer black grapes;

[0058] (2) adding fruit pulp to the crushed grapes for enzymatic hydrolysis; the enzyme used for enzymatic hydrolysis is Pectinex Ultra Color, the amount of enzyme added is 0.01% of the weight of the grapes, and the enzymatic hydrolysis is carried out at 40° C. for 0.3 h;

[0059] (3) pressing and pasteurizing at 90°C for 25 seconds to obtain juice;

[0060] (4) The juice was enzymatically hydrolyzed using 0.02% by weight of Smart Clear pectinase and 0.01% by weight of GA 3X amylase. The juice after enzymatic hydrolysis was ultrafiltered using a filter membrane with a molecular weight cutoff of 10,000 Da (model: UFOLO 98928) at a pressure of ≤1.5 MPa, and then concentrated to 40° Brix by rotary evaporation at 50° C. and 65 rpm / min to obtain a finished concentrated grape juice, and the anthocyanin content thereof was detected.

[0061] Example 3

[0062] A method for increasing anthocyanin content in a concentrated grape juice processing process comprises the following steps:

[0063] (1) Select, wash and crush summer black grapes;

[0064] (2) adding fruit pulp to the crushed grapes for enzymatic hydrolysis; the enzyme used for enzymatic hydrolysis is Pectinex Ultra Color, the amount of enzyme added is 0.01% of the weight of the grapes, and the enzymatic hydrolysis is carried out at 50° C. for 0.8 h;

[0065] (3) pressing and pasteurizing at 95°C for 35 seconds to obtain juice;

[0066] (4) The juice was enzymatically hydrolyzed with 0.02% by weight of Smart Clear pectinase and 0.01% by weight of GA 3X amylase. The juice after enzymatic hydrolysis was ultrafiltered with a filter membrane with a molecular weight cutoff of 10,000 Da (model: UFOLO 98928) at a pressure of ≤1.5 MPa, and then concentrated to 40° Brix by rotary evaporation at 70° C. and 65 rpm / min to obtain a finished concentrated grape juice, and the anthocyanin content thereof was detected.

[0067] Example 4

[0068] Changes of total anthocyanin content during the processing of concentrated grape juice

[0069] Summer black grapes are processed into concentrated grape juice through crushing, pulp enzymolysis, pressing, concentration, juice enzymolysis, ultrafiltration, and concentration. The appearance characteristics are shown in the following order: Figure 1 The total anthocyanin content during the processing was tested using the pH differential method. The trend results are shown in Figure 2 .

[0070] Table 3 Total anthocyanin content in different stages of concentrated grape juice

[0071]

[0072] Table 4 Anthocyanin content growth ratio

[0073] Different sections broken Fruit pulp enzymatic hydrolysis press Basha Juice enzymatic hydrolysis Ultrafiltration concentrate Growth rate% / 127.61 21.31 10.78 14.63 -3.09 -3.39

[0074] like Figure 2 As shown in Table 3, during the entire processing of concentrated grape juice, the total anthocyanin content showed a trend of first increasing and then stabilizing. The largest upward trend was in the enzymatic hydrolysis of the pulp, which increased by 127.61% (see Table 4, Figure 3 ), as shown in the data in Table 4, the relative changes in total anthocyanins were as follows: pulp enzymatic hydrolysis (127.61%) > pressing (21.31%) > juice enzymatic hydrolysis (14.63%) > pasteurization (10.78%).

[0075] The results showed that enzymatic hydrolysis of pulp was the key control point for significantly increasing the anthocyanin content. Therefore, the enzymatic hydrolysis of pulp was taken as the key process point in the processing of concentrated grape juice and the process was optimized with anthocyanin content as an indicator.

[0076] Example 5

[0077] Changes of Monomeric Anthocyanin Content in Concentrated Grape Juice During Processing

[0078] Table 5 Monomeric anthocyanin content in different sections

[0079]

[0080] Combined with Table 5 Figure 4It can be seen that a total of 5 anthocyanin monomers were detected in different processing sections of concentrated grape juice, namely petunidin-3-O-glucoside, chloropeonidin-3-O-glucoside, chloromaldiol-3-O-glucoside, delphinidin-3-O-glucoside, and cyanidin-3-O-glucoside. Among them, petunidin-3-O-glucoside and chloropeonidin-3-O-glucoside were no longer detected in the pasteurization section and later. The reason may be that petunidin-3-O-glucoside is an ortho-diphenol structure anthocyanin, which is degraded during the processing process and the content is reduced. The chloropeonidin-3-O-glucoside aglycone is a glucoside and is substituted at the C3 position. After being processed in the pasteurization section, the content of monomer anthocyanins showed a significant increase compared with the pressing section, because high temperature promoted the dissolution of cell wall pigments to a certain extent. Although some anthocyanins were degraded due to high temperature, the dissolution rate of other monomer anthocyanins increased. Among them, delphinidin-3-O-glucoside and cyanidin-3-O-glucoside were not detected before the pasteurization section, and the dissolution rate of malvaceae chlorogenated pigment-3-O-glucoside increased from 7.08 mg / L to 16.26 mg / L.

[0081] Among the five monomer anthocyanins, malvaceae chlorogenin-3-O-glucoside has the highest content and shows an increasing trend, increasing 19 times during the entire processing process. This is because malvaceae chlorogenin-3-O-glucoside is a non-o-diphenol structure anthocyanin, which reduces the coupled oxidation phenomenon of o-quinone and secondary oxidation products, and the oxidation rate is relatively slow. In addition, polymerization occurs during the pasteurization process to form a more stable structure. It can be determined that the main reason for the change in the total anthocyanin content in different stages of concentrated grape juice is the change in malvaceae chlorogenin-3-O-glucoside, which is determined to be the key monomer anthocyanin.

[0082] Example 6

[0083] Changes of anthocyanins and color values ​​(L value, a* value, b* value) in different processing stages

[0084] Table 6 Color value changes in different processing stages (L value, a* value, b* value)

[0085] -- broken Fruit pulp enzymatic hydrolysis press Basha Juice enzymatic hydrolysis Ultrafiltration concentrate L value 81.36 77.62 67.56 61.93 61.98 65.03 19.92 a* value 10.69 15.35 23.61 27.34 26.01 23.76 40.03 b* value 13.93 14.31 20.21 19.78 22.00 21.08 28.87 ΔE 0.04 6.03 19.96 26.29 26.03 22.15 69.75

[0086] Anthocyanins, as important color-developing components, affect the color change of grape juice during processing. Spearman correlation analysis was performed on key indicators (L value, a* value, b* value) and monomer anthocyanins. By clarifying the color change trend during concentrated grape juice processing, the relationship between color and monomer anthocyanins during processing was further explored. The changes in L value, a* value, and b* value during concentrated grape juice processing are shown in Figure 2. Figure 4, the relevant data are shown in Table 6. As the processing progresses, the L value generally shows a downward trend, and the L value in the concentration section decreases the most, mainly due to the dissolution of pigments during the processing, which causes the color of the grape juice to become darker and the brightness to decrease; the a* value and b* value show an upward trend. The anthocyanin content in the concentrated grape juice processing process continues to increase, making the color of the grape juice reddish and brownish (see Figure 1 ), therefore, the a* and b* values ​​increased accordingly. Compared with the crushed group, the ΔE value gradually increased, and its color value change corresponded to the total anthocyanin content.

[0087] like Figure 5 As shown in the figure, a correlation matrix analysis of monomer anthocyanins and color difference was performed to show the correlation coefficients between different variables. The numbers in the center of the figure represent the correlation coefficients between different variables, ranging from -1 to 1. 1 represents a perfect positive correlation, -1 represents a perfect negative correlation, and 0 represents no correlation. The asterisk (*) indicates that the correlation is statistically significant, with a p-value less than or equal to 0.05. As can be seen from the figure, there is a very strong negative correlation between the L value and the a* value and b* value (-0.95 and -0.94), which may mean that when the L value increases, the a* value and b* value will decrease, and vice versa. In the processing of concentrated grape juice, the three anthocyanin monomers, malvidin-3-O-glucoside, delphinidin-3-O-glucoside and cyanidin-3-O-glucoside detected in the subsequent stage were negatively correlated with the L value, and positively correlated with the a* value and b* value; the chloropeonidin-3-O-glucoside detected in the early stage was negatively correlated with the a* value, b* value and total anthocyanin content. Since chloropeonidin-3-O-glucoside was only detected in the pressing stage and before, and the detected content showed a downward trend, it was not detected in the subsequent stages, indicating that as the processing stage progressed, its content continued to decrease until it could not be detected, while the total anthocyanin content continued to increase, and the sample color turned red, so it was negatively correlated with the a* value, b* value and total anthocyanin content. The total anthocyanin content during the processing was positively correlated with the a* value and b* value, indicating that the higher the content of the three monomers of malvidin-3-O-glucoside, delphinidin-3-O-glucoside, and cyanidin-3-O-glucoside and the total anthocyanin content, the redder the color of the concentrated grape juice, and the darker the overall color.

[0088] Example 7

[0089] Table 7 Total anthocyanin content extracted by different enzymes in the enzymatic hydrolysis section

[0090]

[0091] Eight different types of enzymes were selected to extract anthocyanins in the enzymatic hydrolysis stage. Figure 6It can be concluded that compared with the blank group (crushed grape pulp), enzymatic hydrolysis has a good dissolution effect on total anthocyanins, but different enzymes have different effects on the dissolution rate of total anthocyanins. Among them, Pectinex Ultra Color enzyme (PUC) has the most obvious dissolution effect on total anthocyanins, as shown in Table 7, the total anthocyanin content increased by 297.45%, followed by Rapidase Smart Clear Plus enzyme (SCP), which increased by 279.99%, Pectinex Yddmach Extra enzyme (PYE), which increased by 166.84%, Rohalase BXL enzyme (BXL), which increased by 140.56%, ROHAMENT CL enzyme (CL), which increased by 138.55%, and TF99 enzyme, which increased by 136.76%. The ranking of anthocyanin content after enzymatic hydrolysis is: Pectinex Ultra Color enzyme (PUC) > Rapidase Smart Clear Plus enzyme (SCP) > Pectinex Yddmach Extra enzyme (PYE) > FFY enzyme > Rohalase BXL enzyme (BXL) > ROHAMENTCL enzyme (CL) > TF99 enzyme > FDG enzyme. Pectinex Ultra Color enzyme (PUC) and Rapidase Smart Clear Plus enzyme (SCP) are the dominant enzymes for anthocyanin extraction.

[0092] Example 8

[0093] Table 8 Effect of enzyme types on the content of monomer anthocyanins

[0094]

[0095] During the optimization of enzymatic hydrolysis of fruit pulp, the effects of different enzymes on delphinidin-3-O-glucoside ( Figure 7 ), malvidin-3-O-glucoside ( Figure 8 ) and cyanidin-3-O-glucoside ( Fig. 9 ) The effects of three monomers. As shown in Table 8, the content of malvidin-3-O-glucoside was the highest after all the enzymatic hydrolysis, followed by delphinidin-3-O-glucoside and cyanidin-3-O-glucoside. After the enzymatic hydrolysis of the pulp with Rapidase Smart Clear Plus enzyme (SCP), the dissolution of the two monomers of delphinidin-3-O-glucoside and cyanidin-3-O-glucoside increased significantly, and there was a significant difference in the dissolution effect of the two anthocyanins with the other 6 groups. The effects of different enzymes on the dissolution of the three monomer anthocyanins during the enzymatic hydrolysis of the pulp were comprehensively evaluated, and Rapidase Smart Clear Plus enzyme (SCP) was determined to be the optimal enzyme for anthocyanin extraction.

Claims

1. Use of Rapidase Smart Clear Plus enzyme and / or Pectinex Ultra Color enzyme to increase the anthocyanin content in concentrated grape juice, characterized in that: In the processing of concentrated grape juice, Rapidase Smart Clear Plus enzyme and / or Pectinex Ultra Color enzyme are added to the crushed grapes for enzymatic hydrolysis, and then the grapes are squeezed, sterilized, juice enzymatically hydrolyzed, ultrafiltered and concentrated to obtain concentrated grape juice with high anthocyanin content.

2. The use according to claim 1, characterized in that The anthocyanins include total anthocyanins and at least one of the following monomeric anthocyanins: malvidin-3-O-glucoside, delphinidin-3-O-glucoside, and cyanidin-3-O-glucoside.

3. The use according to claim 1, characterized in that Based on the weight of the crushed grapes, 0.01% Rapidase Smart Clear Plus enzyme or 0.01% Pectinex Ultra Color enzyme is added to the crushed grapes and enzymolyzed at 40-50°C for 0.3-0.8h.

4. A method for increasing the anthocyanin content in concentrated grape juice using Rapidase Smart Clear Plus enzyme and / or Pectinex Ultra Color enzyme, characterized in that: The steps include: (1) Select, wash and crush grapes; (2) Adding fruit pulp to the crushed grapes for enzymatic hydrolysis; the enzyme used is Rapidase Smart Clear Plus enzyme or Pectinex Ultra Color enzyme, the enzyme addition amount is 0.01% based on the weight of the grapes, the enzymatic hydrolysis temperature is 40-50°C, and the enzymatic hydrolysis time is 0.3-0.8h; (3) pressing and pasteurizing at 90-98°C for 25-35s to obtain juice; (4) The juice is enzymatically hydrolyzed, ultrafiltered, and concentrated to obtain the finished concentrated grape juice.

5. The method according to claim 4, characterized in that The grapes in (1) are summer black grapes.

6. The method according to claim 4, characterized in that (4) The juice was enzymatically hydrolyzed using 0.02% pectinase Smart Clear and 0.01% amylase GA 3X at 45-60°C for 0.3-0.8 h.

7. The method according to claim 4, characterized in that (4) In the ultrafiltration, the membrane has a molecular weight cutoff of 10,000 Da and a pressure of ≤1.5 MPa.

8. The method according to claim 4, characterized in that In (4), the concentration condition is to transfer the ultrafiltered grape juice to a rotary evaporator and rotary evaporate at 50-70°C and 65 rpm / min until the sugar content of the grape juice is 40°Brix.

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