Method for improving clarity of tea beer based on compound enzyme

Abstract

The invention relates to a method for improving clarity of tea beer based on compound enzyme, which comprises the following steps: 1) adding protease at a specific stage of a tea beer preparation process for treatment to obtain beer fermentation liquor treated by protease; 2) adding water into tea leaves for extraction, and adding tannase for treatment to obtain a tea leaf extracting solution; and (3) adding the tea leaf extracting solution into the beer fermentation solution in a specific stage of a tea beer preparation process, uniformly mixing, and carrying out membrane filtration, sterilization and filling to obtain a tea beer finished product. According to the method, cold wort or beer fermentation liquor is treated through protease, and protein generated in the wort and yeast fermentation process is efficiently hydrolyzed; the tea leaves are subjected to enzymolysis through tannase, ester type catechin which is easy to form precipitates is hydrolyzed into non-ester type catechin which is not easy to form precipitates, so that the precipitates are reduced, meanwhile, tea polyphenols are reserved, the clarity of the tea beer is greatly improved, and functional components such as catechin are reserved; the prepared product has the advantages of high nutrient content, good stability and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of beer processing, and particularly relates to a method for improving the clarity of tea beer based on a composite enzyme. Background Art

[0002] Tea beer incorporates the flavor and functional ingredients of tea into beer, and has received widespread attention in the market in recent years. Tea polyphenols are not only an important flavor substance in tea, but also have many health benefits such as anti-oxidation, anti-cancer, and hypoglycemic, so they are also the iconic ingredients in tea beer. However, tea polyphenols are very easy to complex with proteins in beer to form precipitation, especially during the low-temperature storage of tea beer, a large amount of turbidity will be produced, which has a significant negative impact on the appearance and quality stability of tea beer. This problem has greatly restricted the development of the tea beer industry.

[0003] The existing technology discloses some technical solutions for improving the clarity of tea beer. The patent document with application number CN202210433846.9 discloses a method for preparing Tibetan tea beer, which uses beer silica gel and PVPP clarifier to adsorb protein and tea polyphenols to achieve a clarifying effect. However, this technical solution will remove a large amount of tea polyphenols, greatly reducing the main component of tea in tea beer. The patent document with application number CN201410044111.2 discloses a tea beer clarifier and a clarification method, which adds blueberry and raspberry juice, extracts or polyphenols to the beer production to act on the turbid part of the tea beer without affecting the body of the beer. Although this method improves the clarity of tea beer to a certain extent, on the one hand, it will introduce blueberries or raspberries to change the flavor of tea beer, and on the other hand, it does not improve the tea juice, and it is still easy to produce precipitation during storage, especially during refrigeration. Summary of the invention

[0004] In view of the problems that proteins and tea polyphenols in tea beer are easily complexed and precipitated, and the stability is very poor, the purpose of the present invention is to provide a method for improving the clarity of tea beer based on a composite enzyme, so as to prepare a tea beer product with high clarity, rich tea polyphenols content and good stability, which is specifically achieved through the following technical solutions: A method for improving the clarity of tea beer based on a composite enzyme, the method comprising the following steps: 1) adding protease treatment at a specific stage of the tea beer preparation process to obtain a beer fermentation liquid treated with protease; 2) Extracting tea leaves with water and adding tannin enzyme to obtain tea extract; 3) In a specific stage of the tea beer preparation process, the tea extract obtained in step 2) is added to the beer fermentation liquid, mixed evenly, and further subjected to membrane filtration, sterilization and filling to obtain the finished tea beer.

[0005] Furthermore, the specific stage in step 1) refers to after the wort is boiled and cooled in the beer preparation process or after the main fermentation is completed.

[0006] Furthermore, the protease in step 1) is a proline endoprotease with an activity of 5 U / g and an addition amount of 0.01-0.02 g / L.

[0007] Furthermore, in step 2), the tannase activity is 500 U / g and the addition amount is 0.1-0.2 g / L.

[0008] Furthermore, the specific stage in step 3) refers to after the fermentation and gas production is completed and after the beer fermentation liquid is treated with protease.

[0009] On the one hand, the present invention uses protease to treat cold wort or beer fermentation liquid to efficiently hydrolyze the protein produced in the wort and yeast fermentation process; on the other hand, tannin is used to enzymolyze tea leaves to specifically hydrolyze the ester-type catechins that are easy to form precipitation in tea polyphenols into non-ester-type catechins that are not easy to form precipitation, thereby reducing the formation of precipitation while retaining tea polyphenols. The technical solution provided by the present invention not only greatly improves the clarity of tea beer, but also retains more tea functional ingredients such as catechins, and the prepared product has the advantages of high nutritional content and good stability.

[0010] The present invention innovatively uses a composite enzyme to hydrolyze substances in tea beer that are prone to precipitate in stages, thereby improving the clarity of tea beer, increasing its stability, and retaining the nutrients to the maximum extent. The protein in tea beer is easily complexed with tea polyphenols to form a precipitate, and the tea polyphenols themselves are also prone to form "cold turbidity" when refrigerated. Most of the previously disclosed technologies use PVPP treatment to remove polyphenols to reduce precipitation, which will greatly reduce the effective ingredients in tea beer. The present invention found that the ester-type catechins in tea polyphenols are easily complexed with proteins in beer to form precipitates, while non-ester-type catechins will not form precipitates, and non-ester-type catechins will not produce "cold turbidity". In addition, the present invention also found that after the protein in beer is complexed with polyphenols to form a precipitate, it is difficult to hydrolyze these precipitates by protease treatment. The present invention adopts a composite enzyme staged treatment method to avoid the above problems: first, the protein in the beer is treated with proline endoprotease to hydrolyze it into amino acids to prevent it from forming precipitation with tea polyphenols; the tea leaves are further treated with tannin to hydrolyze the ester catechins into non-ester catechins, which will not reduce the effective components of the tea leaves, can also avoid the formation of precipitation, and ensure that the tea beer has good stability during refrigeration.

[0011] The technical solution provided by the present invention not only greatly improves the clarity of tea beer, but also retains more tea functional ingredients such as catechins. The prepared product has the advantages of high nutritional content, good stability, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The turbidity comparison of different Longjing tea beer samples in Example 1; Figure 2 To verify the catechin liquid chromatogram of CK and HPT in Example 1; Figure 3 The turbidity comparison of different Tieguanyin tea beer samples in Example 2; Figure 4 This is the liquid chromatogram of catechins for verifying CR and PTR in Example 2. DETAILED DESCRIPTION

[0013] The present invention is further described below in conjunction with specific embodiments. Example 1

[0014] After the malt is crushed, water is added in a ratio of 1:5 to make a mash. The saccharification is carried out by step-by-step heating, gradually increasing the temperature from 40℃ to 78℃, and the total saccharification is 80 min. After the saccharification is completed, it is filtered and washed 3-5 times after filtering. The saccharified wort is boiled in a boiling pot for 60 min, and hops are added after the wort starts to boil. After the boiling is completed, the wort is cooled. The dry yeast is activated and added to the cooled wort for fermentation. The fermentation temperature is 20℃. After 6 days of main fermentation, the temperature is gradually reduced to 4℃, and the bottom yeast is continuously discharged. After the diacetyl value drops below 0.1 mg / L, 5 g / L Longjing tea is added, and the extract is extracted at 4℃ for 3 days. After removing the tea leaves, the CK group is obtained by membrane filtration, sterilization and filling.

[0015] The PE group was treated with Longjing tea and proline endoprotease based on the CK group.

[0016] The PT group was based on the CK group, with Longjing tea added and protease and tannase added for treatment.

[0017] HP group is based on CK group, and protease treatment is added after the main fermentation.

[0018] HPT group was based on CK group, and added protease treatment after the main fermentation; and Longjing tea treated with tannin was added to the beer fermentation liquid after protease treatment.

[0019] The activity of the above-mentioned protease is 5 U / g, and the addition amount is 0.01 g / L. The activity of tannase is 500 U / g, and the addition amount is 0.1 g / L.

[0020] The turbidity of each sample prepared above was measured by a turbidity meter, and the results were as follows: Figure 1 As shown. Figure 1 It can be seen that the turbidity of the CK group was the highest, reaching 48.8 NTU, which indicates that the Longjing tea beer prepared without enzyme treatment has a higher turbidity. The turbidity of the PE group was only 2.9% lower than that of the CK group, which indicates that when the tea is treated with protease at the same time, a large amount of precipitate will still be formed. The turbidity of the HP group was 73.9% lower than that of the CK group, which indicates that after the protease treatment of the beer sample for a period of time, the protein content therein decreased significantly, and the turbidity of the sample prepared by adding tea on this basis decreased significantly. The turbidity of the TE group was 84.2% lower than that of the CK, which indicates that adding tea to beer after treating it with tannase can also significantly reduce the turbidity of tea beer. The sample with the best effect was the HPT group (protease treated beer, tannase treated tea, and then mixed), whose turbidity was reduced by 89.7% compared with CK, which shows that the composite enzyme staged treatment method adopted in the present invention can significantly reduce the turbidity of tea beer.

[0021] Verification Example 1 Catechins are important quality components in tea. Catechins in three kinds of beers were determined by high performance liquid chromatography: the detector was an ultraviolet detector with a detection wavelength of 280 nm. Mobile phase: A was 2% acetic acid, and mobile phase B was pure acetonitrile. Gradient elution was used: 0-16 min, mobile phase B increased linearly from 6.5% to 15%; 16-25 min, mobile phase B increased linearly from 15% to 25%; 25-30 min, mobile phase B decreased linearly from 25% to 6.5%; 30-35 min, mobile phase B was constant at 6.5%. The flow rate was 1 mL / min, the column temperature was 40 ℃, and the injection volume was 10 μL. Standard solutions were prepared with eight catechin standards, and standard curves of standard concentration and peak area were drawn. The concentration of each component was calculated by the peak area of ​​the sample.

[0022] The results of catechins are as follows Figure 2As shown, 8 catechins can be detected in the CK group, while only 5 catechins can be detected in the HPT group, among which the content of ester catechins that are easy to produce turbidity has been greatly reduced (EGCG, GCG, ECG can no longer be detected, and the content of CG has also been greatly reduced). In addition, the content of non-ester catechins (GC, EGC, C, EC) that are not easy to produce turbidity in HPT has increased significantly, which is formed by enzyme catalysis of ester catechins. After calculation, the catechin content of the CK group is 161.8 mg / L (ester catechins account for 31.1%), while the catechin content in the HPT is 209.5 mg / L (ester catechins account for 1.1%), which shows that the composite enzyme treatment can not only promote the dissolution of catechins, but also improve the composition of catechins and greatly reduce the formation of precipitation. Therefore, unlike the traditional adsorption method (such as PVPP, etc.), which will cause a significant decrease in the total amount of catechins, the composite enzyme treatment method provided by the present invention can retain more tea functional ingredients such as catechins while improving the clarity of tea beer. Example 2

[0023] After the malt is crushed, water is added in a ratio of 1:5 to make a mash. Saccharification is carried out by step-by-step heating, gradually increasing the temperature from 40℃ to 78℃, and saccharification is carried out for 80 minutes. After saccharification, it is filtered and washed 3-5 times after filtration. The saccharified wort is boiled in a boiling pot for 60 minutes, and hops are added after the wort starts to boil. After boiling, the wort is cooled. The dry yeast is activated and added to the cooled wort for fermentation. The fermentation temperature is 20℃, and the main fermentation is 6 days later. Add 5 g / L Tieguanyin tea soup obtained by leaching at 95℃ for 10 minutes. Gradually cool down to 4℃, and continuously discharge the bottom yeast. After the diacetyl value drops below 0.1 mg / L, the CR group is obtained by membrane filtration, sterilization and filling.

[0024] The PR group was treated with proline endoprotease after the wort was cooled based on the CR group.

[0025] TR group is based on the CR group, the Tieguanyin tea soup is first treated with tannase and then added to the beer fermentation liquid.

[0026] The PTR group is based on the CK group. After the wort is cooled, proline endoprotease is added for treatment, and the Tieguanyin tea soup is first treated with tannin and then added to the beer fermentation liquid.

[0027] The activity of the above-mentioned protease is 5 U / g, and the addition amount is 0.02 g / L. The activity of tannase is 500 U / g, and the addition amount is 0.2 g / L.

[0028] The turbidity of the above samples was measured by turbidity meter, and the results were as follows: Figure 3 As shown. Figure 3It can be seen that the turbidity of the CK group was the highest, reaching 100.1 NTU, which indicates that the turbidity of the Tieguanyin tea beer prepared without enzyme treatment is higher. The turbidity of the PR group was 76.2% lower than that of the CR group, which indicates that after the wort was treated with protease, the protein content therein decreased significantly, and the turbidity of the sample prepared by adding tea on this basis decreased significantly. The turbidity of the TR group was 82.4% lower than that of the CR group, which indicates that adding tea to beer after treating it with tannase can also significantly reduce the turbidity of tea beer. The sample with the best effect was the PTR group (protease-treated wort, tannase-treated tea), whose turbidity was reduced by 89.3% compared with CK, which shows that the composite enzyme staged treatment method adopted by the present invention can significantly reduce the turbidity of Tieguanyin tea beer.

[0029] Verification Example 2 The results of catechins are as follows Figure 4 As shown, 8 catechins can be detected in the CR group, while only 5 catechins can be detected in the PTR group, among which the content of ester catechins that are easy to produce turbidity has been greatly reduced (EGCG, GCG, ECG can no longer be detected, and the content of CG has also been greatly reduced). In addition, the content of non-ester catechins (GC, EGC, C, EC) that are not easy to produce turbidity in PTR has increased significantly, which is formed by enzyme catalysis of ester catechins. After calculation, the catechin content of the CR group is 214.4 mg / L (ester catechins account for 35.5%), while the catechin content in the HPT is 230.5 mg / L (ester catechins account for 0.9%), which shows that the composite enzyme treatment can not only promote the dissolution of catechins, but also improve the composition of catechins and greatly reduce the formation of precipitation. Therefore, unlike the traditional adsorption method (such as PVPP, etc.), which will cause a significant decrease in the total amount of catechins, the composite enzyme treatment method provided by the present invention can improve the clarity of tea beer while retaining more tea active ingredients such as catechins.

Claims

1. A method for improving the clarity of tea beer based on a composite enzyme, characterized in that: The method comprises the following steps: 1) adding protease treatment at a specific stage of the tea beer preparation process to obtain a beer fermentation liquid treated with protease; 2) Extracting tea leaves with water and adding tannin enzyme to obtain tea extract; 3) In a specific stage of the tea beer preparation process, the tea extract obtained in step 2) is added to the beer fermentation liquid, mixed evenly, and further subjected to membrane filtration, sterilization and filling to obtain the finished tea beer.

2. A method for improving beer clarity based on complex enzymes as claimed in claim 1, characterized in that: The specific stage in step 1) is after the wort has been boiled and cooled in the beer preparation process or after the main fermentation has ended.

3. A method for improving beer clarity based on complex enzymes as claimed in claim 1, characterized in that: The protease in step 1) is a proline endoprotease with an activity of 5 U / g and an addition amount of 0.01-0.02 g / L.

4. A method for improving beer clarity based on complex enzymes as claimed in claim 1, characterized in that: In step 2), the tannase activity is 500 U / g and the addition amount is 0.1-0.2 g / L.

5. The method for improving beer clarity based on composite enzyme according to claim 1, characterized in that: The specific stage in step 3) refers to after the fermentation gas production is completed and the beer fermentation liquid is treated with protease.

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