High-freshness tea leaf theanine wine with stable color and luster and preparation method of high-freshness tea leaf theanine wine

Abstract

The invention discloses high-freshness tea leaf theanine wine with stable color and luster and a preparation method of the high-freshness tea leaf theanine wine, and belongs to the technical field of beverage wine. The preparation method comprises the following steps: processing fresh leaves of a'white leaf No.1 'spring tea later-stage tea tree as raw materials to obtain the high-amino-acid and high-freshness green tea; the high-purity tea leaf theanine is obtained by performing extraction, primary concentration, adsorption separation, secondary concentration and drying on green tea. High-purity tea leaf theanine and base liquor are prepared to obtain the high-freshness high-tea leaf theanine liquor which is stable in color and luster, and the high-freshness high-tea leaf theanine liquor comprises the following components in percentage by mass: 0.1-0.4% of L-theanine, 0.1-0.4% of L-theanine, 0.1-0.4% of L- And the alcoholic strength is 32-52% vol. According to the preparation method provided by the invention, the theanine is naturally extracted from the tea leaves, the prepared high-freshness high-tea-leaf theanine wine is fresh, rich and coordinated in taste, clear and transparent in color and luster, stable and free of browning, and the problems that in the prior art, the yield is low due to direct extraction of L-theanine, and the production cost is low can be effectively solved. The research on the stability, taste expression and the like of the L-theanine in an alcohol system is unknown.

Description

Technical Field

[0001] The invention belongs to the technical field of beverage wines, and in particular relates to a high-flavor tea theanine wine with stable color and a preparation method thereof. Background Art

[0002] The tea industry and the wine industry are both traditional Chinese industries. After thousands of years of market competition and selection, tea and wine still have strong vitality. In the era of rapid technological development and diversified and healthy consumer demand, the tea and wine industries are in the stage of transformation and upgrading. The innovation of tea and wine products meets the needs of high-quality and rapid development of the tea and wine industries, and meets the consumer demands of "health, diversity, and fashion" in the context of the era of great health, and has a very broad market prospect.

[0003] Research shows that "Bai Ye No. 1" is a naturally mutated thermosensitive albino tea variety. The albino phenomenon is most obvious around the one bud and two leaves stage of the new shoots in spring. At this time, the amino acid content reaches a peak value. The free amino acid content in the Anji white tea is >5.0%, which is significantly higher than that of conventional green tea varieties such as "Longjing 43" and "Jiukeng". Anji white tea, which is positioned as a high-end green tea, only harvests one bud and two leaves of the spring shoots, and the picking period is only more than 20 days a year. Research shows that the fresh leaves of Anji "Bai Ye No. 1" in the greening period (April to July) have good processing adaptability in green tea and black tea. Through sensory evaluation and physical and chemical analysis, the results show that the free amino acid content in the trial-produced green tea and black tea is still higher than that of general tea varieties, some of which are above 4.0%. The product tastes fresh and pure, showing the variety characteristics of "Bai Ye No. 1", and the raw material cost is low, which is an excellent raw material for the preparation of natural tea theanine.

[0004] L-Theanine is a characteristic amino acid of tea, also known as tea theanine, accounting for about 50% to 60% of the total amino acids in tea. Naturally occurring theanine is L-type, and pure products are white needle-shaped crystals. It is highly soluble in water, insoluble in organic solvents such as ethanol and ether, and its aqueous solution is slightly acidic, with a caramel aroma and a fresh taste similar to that of MSG. Its taste threshold in water is 0.06%, which is the main material basis of the umami flavor of tea and is strongly positively correlated with the quality of green tea. Studies have shown that L-theanine has health benefits such as anti-tumor, soothing nerves, anti-depression, lowering blood pressure, and weight loss, and has great application prospects in the fields of health and function.

[0005] At present, the preparation of L-theanine is divided into chemical synthesis, biosynthesis and direct extraction of tea leaves. Chemical synthesis of theanine has the advantages of simple method, low cost and high yield. It has become the main source of raw materials or auxiliary materials for theanine medicine and food applications in Japan, the United States, Canada and other countries. However, it is also well known that chemical synthesis is difficult to purify, has pollution and toxicity, and the theanine directly obtained by chemical synthesis is generally DL-type racemate, which is extremely difficult to purify and obtain L-theanine. With the development and application of biotechnology, the method of using strain selection and fermentation to produce enzymes and then using the produced enzymes to promote the growth of theanine has become a research hotspot. It has greatly improved the preparation efficiency of high-purity theanine to a certain extent, but there are still many problems to be solved to be widely used in industrial production. The direct extraction of tea leaves usually adopts a method of differential separation and modular preparation of active substances such as tea polyphenols and caffeine in tea leaves. The obtained L-theanine has the characteristics of natural, green, high safety, short production cycle, high product quality and low cost, but because of its large content in tea leaves, the yield is often low. It is necessary to start from the source of fresh leaves and process them to obtain tea raw materials with high theanine content.

[0006] At the same time, there are still few reports on the stability and taste expression of L-theanine in alcohol systems, which urgently need to be further studied. Summary of the invention

[0007] The invention aims at the technical problems that the direct extraction rate of L-theanine is low, the stability of L-theanine in an alcohol system, the taste expression and the like are still unclear, and provides a high-freshness tea theanine wine with stable color and a preparation method thereof.

[0008] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0009] In a first aspect, the present invention provides a method for preparing a high-flavor tea theanine wine with stable color, which specifically comprises the following steps:

[0010] S1 uses fresh leaves of the "White Leaf No. 1" tea tree as raw materials to produce green tea leaves with high amino acid content and high freshness;

[0011] S2: extracting, concentrating once, separating by adsorption, concentrating twice, and drying the green tea leaves obtained in step S1 to obtain high-purity tea L-theanine;

[0012] Preparation of S3 theanine wine: The obtained L-theanine is compounded with base wine to obtain a color-stable high-fresh tea theanine wine, which contains 0.1-0.4wt% L-theanine and has an alcohol content of 32-52%vol.

[0013] In the above preparation method, in step S1, the "White Leaf No. 1" tea tree fresh leaves are late spring tea, maintaining the albino characteristics of "white leaves and green veins", and the picking time is April 6-30, and the picking standard is one bud and two or three leaves.

[0014] In the above preparation method, in step S1, the processing technology includes spreading, killing, sorting and drying.

[0015] Furthermore, the green spreading is intermittent air-blast green spreading, and the process conditions are: the green spreading thickness is 0.8-1.2 kg / m 2 After the initial blowing for 10 minutes, stop blowing, and blow for 10 minutes every 60 minutes, for a total of 4 to 6 times. The total spreading time is 220 to 360 minutes.

[0016] Furthermore, the drying includes primary drying and secondary drying.

[0017] In the above preparation method, in step S1, the content of free amino acids in the high-amino acid and high-freshness green tea leaves is

[0018] ≥3.5%.

[0019] In the above preparation method, in step S2, the extraction method is: green tea leaves are subjected to water extraction, centrifugation, microfiltration, and ultrafiltration to obtain a high-amino acid tea extract.

[0020] Furthermore, the tea-to-water ratio of the water extraction is 1:10-1:20, the extraction temperature is 40-95° C., and the extraction time is 40-80 min.

[0021] Furthermore, the content of free amino acids in the high-amino acid tea extract is ≥12.0%.

[0022] In the above preparation method, in step S2, tea concentrate is obtained by one concentration, and the solid content of the tea concentrate is 3-15%.

[0023] In the above preparation method, in step S2, the adsorption separation method is: performing adsorption separation with macroporous resin A and collecting the effluent; performing adsorption separation with macroporous resin B, eluting the macroporous resin B with water and collecting the eluate.

[0024] Furthermore, the sample is passed through a chromatography column filled with macroporous resin A at a loading flow rate of 1 to 3 column volumes / hour.

[0025] Furthermore, the free amino acid content in the effluent is ≥30.0%.

[0026] In the above preparation method, in step S2, the purity of the high-purity tea L-theanine is ≥98%.

[0027] In a second aspect, the present invention provides a high-flavor tea theanine wine with stable color prepared by the above preparation method.

[0028] Beneficial effects:

[0029] (1) The obtained high-amino acid and high-freshness green tea has an amino acid content of >3.5%. The present invention utilizes the discarded fresh leaves of "White Leaf No. 1" spring tea in the later period, innovatively introduces an indirect air-blast spreading process in the tea spreading process, and optimizes the processing technology of low-cost high-amino acid and high-freshness green tea based on the quality indicators of tea amino acid content and freshness.

[0030] (2) The present invention systematically studies the flavoring law and stability of tea theanine in an alcohol system, and for the first time discovers that tea theanine degrades and browns in an alcohol system, filling the gap in the changing law of tea theanine in an alcohol system. At the same time, the flavor expression of tea theanine in an alcohol system is digitally characterized, thereby optimizing the high-flavor, high-amino acid wine, which has the characteristics of fresh, rich, and coordinated taste, clear and transparent color, and stable without browning, thereby improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a process flow chart of the preparation of the high-flavor tea theanine wine with stable color according to an embodiment of the present invention;

[0032] Figure 2 This is a radar chart of the taste of different concentrations of L-theanine in liquor;

[0033] Figure 3 This is the taste radar chart of L-theanine in different ethanol concentrations;

[0034] Figure 4 The appearance changes of L-theanine wines with different concentrations before and after storage for 19 months;

[0035] The left picture shows the appearance of L-theanine wines with different concentrations at the beginning of storage (from left to right, they are control group, concentration 1, concentration, concentration 3, and concentration 4), and the right picture shows the appearance of L-theanine wines with different concentrations after storage for 19 months (from left to right, they are control group, concentration 1, concentration, concentration 3, and concentration 4);

[0036] Figure 5 The content changes of L-theanine wine with different concentrations after storage for 19 months;

[0037] Figure 6 The color changes of high-concentration L-theanine wine at different storage times;

[0038] in, Figure 6 From left to right, they are storage for 0 months, storage for 4 months, storage for 9 months, storage for 12 months, and storage for 12 months;

[0039] Figure 7 The content changes of high-concentration L-theanine wine after 12 months of storage. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clear, the present application is further described in detail below in combination with the implementation methods. Unless otherwise defined, all scientific and technological terms used herein have the same meanings as understood by ordinary technicians in the field.

[0041] The invention discloses a method for preparing high-fresh tea theanine wine with stable color.

[0042] The preparation method comprises: using "White Leaf No. 1" late spring tea tree fresh leaves as raw materials, obtaining high-amino acid and high-freshness green tea through processes such as spreading, killing, straightening, and drying; extracting the green tea, concentrating once, separating by adsorption, concentrating twice, and drying to obtain high-purity tea theanine (L-theanine).

[0043] Further systematic research based on the flavor law of L-theanine in alcohol system proved that when L-theanine>0.06%, it has umami expression in Luzhou-flavor liquor; when the alcohol concentration is between 32% and 52% vol, the umami and salty taste of L-theanine in alcohol is significantly increased, and the sour taste is suppressed, which improves the flavor coordination of L-theanine liquor.

[0044] Based on a further systematic study on the stability of L-theanine in alcohol systems, it was discovered for the first time that L-theanine dynamically degrades in alcohol systems and tends to stabilize after 16 months of storage. High-concentration L-theanine (≥0.6%) wines are also accompanied by browning. Specifically, when the initial concentration of L-theanine is 0.1%, its concentration tends to be stable after 19 months of storage and is >0.06%; when the L-theanine concentration is ≤0.4%, no browning occurs during storage (12 months).

[0045] Based on this, the high-purity tea theanine prepared above is optimized and formulated with base wine to obtain a color-stable high-freshness high-tea theanine wine, including (by mass percentage): L-theanine, 0.1-0.4%; alcohol content, 32-52% vol. The preparation method of the color-stable high-freshness tea theanine wine provided by the present invention, theanine is extracted from natural tea leaves, and the obtained high-freshness high-tea theanine wine has a fresh, rich and coordinated taste, and a clear and transparent color, stable and non-browning.

[0046] Specific examples will be listed below to explain the scheme of the present invention. It will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the examples, the techniques or conditions described in the literature in this area or the product instructions are used. Reagents or instruments used that do not indicate manufacturers are all conventional products that can be obtained commercially.

[0047] Example

[0048] Example 1: Processing of high amino acid and high freshness green tea

[0049] Using the fresh leaves of "White Leaf No. 1" at the end of spring tea season (April 9-10) as raw materials, the technology of high amino acid and high freshness green tea was studied. In view of the traditional continuous air-blasting and green-spreading process of Anji white tea, a new scheme of intermittent air-blasting and green-spreading was proposed, and the effects of different fresh leaf green-spreading processes on the flavor quality of tea were studied.

[0050] (1) Sensory quality

[0051] The effects of different spreading techniques on the sensory (flavor) quality of tea are shown in Table 1.

[0052] Table 1 Effects of different tea spreading processes on the sensory (flavor) quality of tea

[0053]

[0054] As shown in Table 1, on April 9, the tea 2 produced by the tea spreading process 2 was superior to the tea 1 in terms of aroma and flavor, showing a fresher and more tender aroma; a more mellow and fresh taste. The next day, the intermittent tea spreading process was further verified on the tea production line. Because the fresh leaves on April 10 were older than those on April 9, the intermittent tea spreading time in the tea spreading process 4 was extended to 300 minutes. The tea spreading process of this production line was used as a control. The results were consistent with those on April 9. The intermittent tea spreading had a more delicate aroma; the taste was more mellow and slightly fresh.

[0055] (2) Physical and chemical quality

[0056] Further research on its physical and chemical quality, the results are shown in Table 2, the same grade of fresh leaves, intermittent spreading can effectively reduce the tea polyphenols and phenol-ammonia ratio of tea compared with the traditional spreading process. On April 9, the tea polyphenols of the test sample dropped from 15.9% to 15.0%, and the phenol-ammonia ratio dropped from 3.61 to 3.41; on April 10, the tea polyphenols dropped from 17.0% to 16.6%, and the phenol-ammonia ratio dropped from 5.00 to 4.61.

[0057] Table 2 Effects of different spreading processes on the physical and chemical quality of tea

[0058] Tea 1 Tea 2 Tea 3 Tea 4 Water extract(%) 48.0 47.8 48.8 49.9 Tea polyphenols (%) 15.9 15.0 17.0 16.6 Caffeine(%) 3.33 3.22 3.75 3.72 Theanine(%) 1.77 1.72 1.36 1.34 Free amino acids (%) 4.4 4.4 3.4 3.6 Moisture (%) 3.48 3.30 3.64 3.36 GABA(mg / 100g) 68.32 55.91 38.97 40.69 EGC (%) 2.26 2.30 2.29 2.27 C(％) 0.49 0.54 0.43 0.43 EC(%) 0.88 0.95 0.86 0.88 EGCG (%) 8.53 8.12 9.34 9.36 ECG (%) 1.57 1.46 1.82 1.80 Total catechins (%) 13.74 13.37 14.75 14.72

[0059] Combined with the actual production, further experiments and optimization were conducted to obtain the intermittent green tea processing technology with high amino acid and high freshness: the fresh leaves of the "White Leaf No. 1" tea tree are from April 6 to 30, maintaining the whitening characteristics of "white leaves and green veins", and the picking standard is one bud and two or three leaves. The intermittent air-blast green tea process is: the green tea thickness is 0.8-1.2kg / m 2 At the beginning of spreading, stop blowing after 10 minutes, blow for 10 minutes every 60 minutes, blow 4 to 6 times in total, and spread for 220 to 360 minutes. The processing technology of spreading green leaves is: killing green leaves → straightening (initial drying) → initial baking → re-baking; the free amino acid content of the obtained high-amino acid and high-freshness green tea is ≥3.5%.

[0060] Example 2: Taste expression of L-theanine in an alcohol system

[0061] (1) Using 42% vol Luzhou-flavor liquor as solvent, the high-purity L-theanine obtained by the present invention was used to prepare 0, 0.04, 0.06, 0.08, and 0.10% L-theanine solutions, and the umami expression of different concentrations of L-theanine in liquor was studied by sensory evaluation. The results showed that when the concentration of L-theanine was ≤0.06%, the reviewers did not taste the umami, but when the concentration of L-theanine was 0.04%, the umami response value of the electronic tongue was significantly higher than that of the group without addition; when the concentration was ≥0.08%, the umami perceived by the sensory evaluation and the electronic tongue increased significantly, indicating that a certain amount of L-theanine added can significantly enhance the umami of Luzhou-flavor liquor. Modern scientific research shows that the taste threshold of L-theanine in water is 0.06% (similar to the fresh taste of MSG). In this study, the umami expression concentration of L-theanine in Luzhou-flavor liquor needs to be greater than 0.06%, which may be related to the stimulation of ethanol on taste buds or other flavor substances in liquor affecting the umami expression of L-theanine.

[0062] (2) Based on electronic tongue technology, the taste expression of L-theanine at different concentrations in Luzhou-flavor liquor was studied. Figure 2 , as shown in Table 3:

[0063] Table 3 Taste expression of different concentrations of L-theanine in liquor

[0064] L-Theanine Concentration SRS GPS STS UMS SPS SWS BRS 0％ <![CDATA[651.11 a ]]> <![CDATA[1020.88 a ]]> <![CDATA[379.51 a ]]> <![CDATA[950.12 a ]]> <![CDATA[971.50 a ]]> <![CDATA[1106.18 a ]]> <![CDATA[1472.47 a ]]> 0.04％ <![CDATA[684.37 b ]]> <![CDATA[1038.06 a ]]> <![CDATA[472.03 b ]]> <![CDATA[1014.83 b ]]> <![CDATA[1035.62 b ]]> <![CDATA[1151.40 b ]]> <![CDATA[1474.03 a ]]> 0.06％ <![CDATA[693.63 b ]]> <![CDATA[1040.6 a ]]> <![CDATA[539.88 bc ]]> <![CDATA[1024.54 b ]]> <![CDATA[1043.87 b ]]> <![CDATA[1150.28 b ]]> <![CDATA[1470.22 a ]]> 0.08％ <![CDATA[717.15 c ]]> <![CDATA[1056.39 a ]]> <![CDATA[566.80 c ]]> <![CDATA[1065.39 c ]]> <![CDATA[1070.39 bc ]]> <![CDATA[1171.69 bc ]]> <![CDATA[1495.09 a ]]> 0.10％ <![CDATA[714.71 c ]]> <![CDATA[1048.31 a ]]> <![CDATA[538.59 bc ]]> <![CDATA[1058.99 c ]]> <![CDATA[1065.68 bc ]]> <![CDATA[1172.10 bc ]]> <![CDATA[1487.68 a ]]> 0.16％ <![CDATA[743.92 d ]]> <![CDATA[1073.33 a ]]> <![CDATA[583.52 c ]]> <![CDATA[1087.57 c ]]> <![CDATA[1102.26 c ]]> <![CDATA[1182.61 c ]]> <![CDATA[1506.07 a ]]> 1.00％ <![CDATA[871.46 e ]]> <![CDATA[1194.7 b ]]> <![CDATA[761.91 d ]]> <![CDATA[1197.14 d ]]> <![CDATA[1207.28 d ]]> <![CDATA[1213.51 d ]]> <![CDATA[1601.72 a ]]>

[0065] Electronic tongue UMS (umami) perception results Figure 2 As shown, with the increase of L-theanine concentration, the umami perception intensity in Luzhou-flavor liquor gradually increased. When the concentration was 0.04% and 0.06%, the umami perception intensity was significantly higher than that of the non-added group; when the concentration was greater than 0.06%, that is, 0.08-0.16%, the umami perception intensity was extremely significantly higher than that of the non-added group, and significantly higher than the 0.04% and 0.06% groups.

[0066] This study also found that with the increase of L-theanine concentration, it has a certain strengthening effect on the expression of sour, sweet and salty tastes in liquor. The changing trends of sourness (SRS), saltiness (STS) and sweetness (SWS) perception intensity are basically consistent with the changing trends of umami perception, but it has no significant effect on the expression of bitterness in liquor.

[0067] (3) The taste expression of 0.08% L-theanine in different ethanol concentrations (0%, 2.00%, 12.00%, 22.00%, 32.00%, 42.00%, 52.00%) was studied. The results are as follows: Figure 3 , as shown in Table 4. The same concentration of L-theanine has certain differences in taste expression in different ethanol concentrations. With the increase of ethanol concentration, the perception of sourness (SRS), saltiness (STS), and umami (UMS) of L-theanine in ethanol solution changes significantly, while there is no significant difference in sweetness (SWS) and bitterness (BRS).

[0068] When the ethanol concentration is 42.00% and 52.00%, the sour taste expression of L-theanine in ethanol is inhibited, and its acidity perception value is significantly lower than that in pure water and low ethanol concentration (2-32%) conditions, indicating that high concentration ethanol has a certain clamping effect on the sour taste expression of L-theanine ethanol solution.

[0069] The results of salty taste perception showed that there was no significant difference in the umami expression of L-theanine between the pure water group and the ethanol concentration (2-32%) group. As the ethanol concentration further increased, its salty taste expression was enhanced. Under 42% ethanol conditions, its salty taste expression was higher than that of the 0-32% group. Under 52% ethanol conditions, its salty taste expression was significantly higher than that of the 0-32% group, indicating that high concentration ethanol has a certain enhancing effect on the salty taste expression of L-theanine.

[0070] Table 4 Taste expression of L-theanine in different ethanol concentrations

[0071]

[0072]

[0073] The effects of different concentrations of ethanol on the umami expression of L-theanine are similar to those on the expression of salty taste, but the changes in umami expression are more sensitive to ethanol concentration. The results of this study show that when the ethanol concentration is 32-52%, the umami expression of L-theanine is enhanced, which is significantly higher than that of the pure water group and the 2-22% group.

[0074] In summary, the interaction between umami substances and sour, sweet, bitter and salty tastes in the liquor system is somewhat different from that in the water system: the umami perception concentration in 42% vol Luzhou-flavor liquor is >0.06% (mass concentration), low concentration of ethanol (0-22.00%) has no effect on the taste expression of L-theanine, and when the ethanol concentration is 32-52%, the umami and salty taste of L-theanine in ethanol is significantly increased, and the sour taste is inhibited. In this study, the ethanol concentration has no effect on the bitterness of L-theanine.

[0075] It shows that when the concentration of tea theanine in Luzhou-flavor liquor is 0.06-1% and the alcohol content is 32-52% vol, the taste is fresh, rich and harmonious.

[0076] Example 3: Study on the stability of L-theanine in alcohol system

[0077] (1) Study on the storage stability of L-theanine wine with different concentration gradients

[0078] In Example 2 of the present invention, different addition amounts (0, 0.04, 0.06, 0.08, 0.10%, i.e., 0, 375.27, 562.91, 750.54, 938.18 μg / mL) of L-theanine wine were subjected to indoor room temperature storage experiments to study the storage changes of L-theanine in the Luzhou-flavor liquor system.

[0079] The results of the storage experiment of different concentrations of L-theanine wine are as follows: Figure 4 , 5 As shown, L-theanine wines with different concentrations were clear, transparent and colorless at the beginning of storage, and remained clear, transparent and colorless after being stored at room temperature and light conditions for 19 months.

[0080] After 13 months of storage, L-theanine at different concentrations decreased significantly, with concentrations 1 to 4 decreasing by 35.78%, 45.41%, 40.74%, and 32.10%, respectively. In the 16th month of storage, L-theanine decreased slightly compared with the 13th month, and stabilized in the 19th month. This proves that L-theanine degrades during storage and stabilizes as storage time increases.

[0081] (2) Study on the storage stability of high concentration L-theanine wine

[0082] The results of the experimental stage of high-concentration L-theanine wine storage at room temperature and light are as follows Figure 6 , 7 As shown in the figure, the L-theanine wine had no obvious changes in appearance within one month of storage: it was clear, transparent and colorless; it began to turn brown in the second month, and the color gradually deepened, while remaining clear. However, the base wine (blank control) had no change in appearance after being stored for 12 months.

[0083] L-theanine in high concentration tea amino acid wine ( Figure 7 ) The initial concentration was 9.38 mg / mL (1.00%). After 1 month of storage at room temperature and light, there was no significant change in the L-theanine concentration. After 4 months of storage, it was found that the L-theanine content decreased significantly to 8.54 mg / mL, a decrease of about 10%. During the storage period of 4 to 12 months, the L-theanine content decreased slowly and tended to equilibrium. After 12 months of storage, the content was 7.96 mg / mL.

[0084] Based on this, further studies have shown that when the initial concentration of L-theanine is ≤0.4%, it remains clear and transparent in Luzhou-flavor liquor (stored for 12 months) without browning.

[0085] In summary, during the storage process, the content of L-theanine in 42% vol Luzhou-flavor liquor showed a trend of first decreasing and then tending to equilibrium. When the initial concentration was 0.1%, its concentration was still greater than 0.06% after long-term storage. Combined with the results of Example 2, it can be seen that at this concentration, L-theanine has a certain umami expression in Luzhou-flavor liquor.

[0086] Combined with the research results of Example 2, the tea theanine content in the high-fresh tea theanine wine with stable color is 0.1-0.4%, the base wine of Luzhou-flavor liquor has an alcohol content of 32-52% vol.

Claims

1. A method for preparing a high-quality tea theanine wine with stable color, characterized in that: The steps include: S1 uses fresh leaves of "White Leaf No. 1" tea tree as raw materials to produce green tea leaves with high amino acid content and high freshness; S2: extracting, concentrating once, separating by adsorption, concentrating twice, and drying the green tea leaves obtained in step S1 to obtain high-purity tea L-theanine; Preparation of S3 theanine wine: The obtained L-theanine is compounded with base wine to obtain a color-stable high-fresh tea theanine wine, which contains 0.1-0.4wt% L-theanine and has an alcohol content of 32-52%vol.

2. The method for preparing the color-stable high-fresh tea theanine wine according to claim 1, characterized in that: In step S1, the "White Leaf No. 1" tea tree fresh leaves are late spring tea leaves that maintain the albino characteristics of "white leaves and green veins". The picking time is April 6 to 30, and the picking standard is one bud and two or three leaves.

3. The method for preparing the color-stable high-fresh tea theanine wine according to claim 1, characterized in that: In step S1, the processing technology includes spreading, killing, sorting and drying; The processing technology at least meets one of the following requirements: The green spreading is intermittent air blast spreading, and the process conditions are: the green spreading thickness is 0.8-1.2 kg / m 2 , stop blowing after 10 minutes of initial blowing, and blow for 10 minutes every 60 minutes, for a total of 4 to 6 times, and the total time for spreading is 220 to 360 minutes; The drying includes primary drying and secondary drying.

4. The method for preparing the color-stable high-fresh tea theanine wine according to claim 1, characterized in that: In step S1, the content of free amino acids in the high-amino acid and high-freshness green tea leaves is ≥3.5%.

5. The method for preparing the color-stable high-fresh tea theanine wine according to claim 1, characterized in that: In step S2, the extraction method is: green tea leaves are subjected to water extraction, centrifugation, microfiltration, and ultrafiltration to obtain a high-amino acid tea extract; the tea-to-water ratio of the water extraction is 1:10 to 1:20, the extraction temperature is 40 to 95° C., and the extraction time is 40 to 80 minutes.

6. The method for preparing the color-stable high-flavor tea theanine wine according to claim 5, characterized in that: The content of free amino acids in the high-amino acid tea extract is ≥12.0%.

7. The method for preparing the color-stable high-flavor tea theanine wine according to claim 1, characterized in that: In step S2, tea concentrate is obtained by one concentration, and the solid content of the tea concentrate is 3-15%.

8. The method for preparing the color-stable high-flavor tea theanine wine according to claim 1, characterized in that: In step S2, the adsorption separation method is: performing adsorption separation with macroporous resin A and collecting the effluent; passing the effluent through macroporous resin B for adsorption separation, eluting the macroporous resin B with water and collecting the eluate; the adsorption separation with macroporous resin A is performed at a loading flow rate of 1 to 3 column bed volumes / hour through a chromatography column containing macroporous resin A; the free amino acid content in the effluent is ≥30.0%.

9. The method for preparing the color-stable high-flavor tea theanine wine according to claim 1, characterized in that: In step S2, the purity of the high-purity tea L-theanine is ≥98%.

10. High-freshness tea theanine wine with stable color, characterized by: The method is prepared according to any one of claims 1 to 9.

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