JPS6053567B2 - Green tea quality improvement method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for improving the quality of green tea.

More specifically, it is characterized in that a solution containing monoethylamine and/or monomethylamine and an amino acid solution obtained by decomposing various proteins is administered to the leaf surface of the tea plant several times from the budding stage until harvesting. The younger the buds are picked, the higher quality tea can be obtained, but the distribution of amino acids contained in green tea with an opening degree of 10 and picked 5 days before the optimum picking time and the second green tea has a unique composition. Theanine (glutamic acid ethylamide) accounts for 50-7% of all amino acids, and is the next method for improving the quality of green tea.

The quality of tea is determined by its shape, color, light blue, aroma, and taste, and among these, tea with the best taste is considered to be of high quality.

Flavor components in green tea include amino acids, tannins, caffeine, sugar, etc., but the difference in the content of each of these components between high-grade tea and low-grade tea is largely due to the content of amino acids. As shown in Table 1 below, there are large differences in the content of major amino acids depending on the type of fertilizer.

Table (Unit: mg/100V) The amino acid content of the green teas harvested at 5゜appropriate period for picking varies widely as shown in Table 2 below.

Table (Unit beat/100V) Sorrow/Kuichiko - Irayog 4 Retami <-- Serine with glutamic acid, aspartic acid,
It has a high content of four amino acids, arginine and serine, and these five amino acids account for 9% of the volume, and GMA (glutamic acid methylamide) plays an important role in taste.

Attempts have been made to improve the taste by artificially adding these flavor components, but the taste obtained by such methods is temporary, and the taste is not noticeable after the first brew. However, by the second and third brewing, the tea loses its flavor and gives an unnatural taste, so it cannot be considered a high-quality tea.

As a result of repeated research, the present inventor focused on the fact that amino acids are absorbed and utilized from the leaf surface, and that monoethylamine and monomethylamine are absorbed from the leaf surface and combine with glutamic acid in the leaf to produce theanine and GMA. The present invention was completed based on the new knowledge that it is possible to increase the amount of theanine and GMAl amino acids in green tea and obtain a high-quality tea that maintains its natural flavor.

Theanine and GMA, which are flavor components that specifically accumulate in the sprout region of green tea during sprout elongation, can only be biosynthesized in the roots under normal cultivation conditions.

However, other amino acids such as glutamic acid, which serves as a receptor for ethylamine and is a raw material for theanine, and other amino acids can also be biosynthesized in the leaves. Therefore, whether a tea becomes a high-grade tea or remains a low-grade tea under normal cultivation conditions is determined by the stored nutrients accumulated in the roots during the period from autumn to early spring of the following year. In order to artificially produce high-quality tea, there is a method of plucking tea while the buds are young, that is, when a large amount of theanine is accumulated compared to the dry matter production of the buds, and a method of harvesting the tea by cutting out sunlight. Theanine once accumulated. There are two light-shielding culturing methods that prevent tea from metabolically decomposing and losing its flavor, but the former produces high quality tea but has the drawback of low yields, while the latter requires a lot of materials and labor. Therefore, it has the disadvantage of high cost.

According to the quality improvement method of the present invention, monoethylamine and/or monomethylamine is absorbed from the leaf surface and combined with glutamic acid, which has been produced and accumulated in the leaves, to produce theanine, which is normally biosynthesized only in the roots under cultivation. By biosynthesizing and/or GMA in leaves and translocating it to new shoots, high-quality tea can be easily harvested.

The amino acids used in combination have the effect of preventing ethylamine and/or methylamine from being consumed in the biosynthesis of amino acids other than theanine and GMA, and actively enhance the taste of the complex amino acids, thereby imparting the unique subtle flavor of green tea. It is useful for producing harmonious high-quality tea.

The solution used in the present invention is a solution containing ethylamine hydrochloride and/or methylamine hydrochloride and an amino acid solution obtained by decomposing various proteins.

Amino acids include various proteins such as plant and animal proteins,
Solutions obtained by decomposing microbial cells by known methods and various amino acid fermentation solutions can be used.

The amino acids contained in these solutions include lysine, histidine, arginine, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine,
These include cystine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, and hydroxyproline. The solution used in the present invention can also contain inorganic salts used as plant nutrients such as ammonium salts, phosphates, potassium salts, and urea.

There are no particular restrictions on the ratio of amine to amino acid, but a weight ratio of 1:5 to 1:2 is preferably used. The concentration of amines and amino acids in the solution used in the present invention may be any concentration, but the total concentration is 0.0
About 4 to 0.5% by weight is preferably used.

There is no particular limit to the amount of removal per 103, but due to the amount of tea leaves spread, it is necessary to remove 200e to 600e with a solution of the above concentration.
A range of is suitable. The solution used in the present invention is usually an aqueous solution, but any solution can be used as long as it is harmless to tea plants. Depending on the purpose, a harmless spreading agent such as CMC, PVAl, sodium alginate, or It is also possible to use various nonionic or anionic surfactants in combination.

This solution is usually applied 3 times a week starting 3 weeks before the green tea is harvested.
For second-tier tea, it is preferable to administer it once a week immediately after picking the first-tier tea, but administration at other intervals is also acceptable.

This solution is usually used by spraying it on the leaves of tea plants, but it can also be effective when applied to the soil.

This will be explained in detail below using examples. Example 1 A quality improvement test by foliar removal was conducted by setting four areas: no withdrawal area, amino acid area (using only amino acids), amine area (using only amines), and amino acid amine area (according to the present invention).

Table 3 shows the composition of the solution used by the Yabukita 8th grade tea garden tested.

The amount of amino acid amine used was standardized based on the amount of nitrogen.

The withdrawal period and the areas without application and test areas will be announced on May 10th.
The tea was harvested using a mortar and processed according to the conventional method for producing green tea, and each product was analyzed for free amino acids and theanine.

The results were as shown in Table 4. The tea from the non-spreading area and the experimental area was evaluated by 10 technicians related to green tea production, including agricultural improvement extension office technical staff, agricultural cooperative farming instructors, tea manufacturers, and tea production graduates, giving a perfect score of 5 points for each section in Table 5. The quality was evaluated using a sensory test and was scored on a scale of 1.

The results are shown in Table 5. The amino acid amine group received high evaluations for all items, but particularly for taste.

The taste of the amino acid group had umami, but it tended to be sweet, and many people commented that the taste was a bit unreliable.

Claims (1)

[Claims] 1. A method for improving the quality of green tea, which comprises administering to the leaf surface of a tea plant a solution containing monoethylamine and/or monomethylamine and an amino acid solution obtained by decomposing various proteins.