Quantitative changes in volatile components of green tea during development of tea shoots [Japanese]

摘要

The quantitative changes in volatile components of green tea (sen-cha) were investigated during the development of tea shoots. The tea shoots were picked and processed seventeen times at intervals of several days in the season of first and second crop. The sensory test scores of two antithetic odors, called "Wakame-ka (Mirume-ka)" and "Kowaba-shu", were correlated with the content of neutral detergent fiber, because these odors were influenced by the maturity degree of tea shoots. The odor concentrates from above green tea samples were prepared by an adsorptive column method. One hundred twenty eight compounds were individually quantified by GC and 75 of them were identified by GC-MS. The quantitative changes in volatile compounds were analyzed by principal component analysis. (E,E)-2,4-heptadienal, (EZ)-2,4-heptadienal, (Z)-2-penten-1-ol, hexanal and (Z)-2-heptenal increased during the development of tea shoots. These components were possible contributors to Kowaba-shu". Linalool oxide (cis-pyranoid), coumarin, 7,8-dihydro-beta-ionone, (E)-2-hydroxycinnamic acid and heptanoic acid decreased during the development of tea shoots. These components seemed to contribute to "Wakame-ka". Linalool, geraniol and linalool oxide (furanoid) increased markedly during the development of tea shoots in first crop season but did not in second crop season. Therefore, these components were hardly considered to contribute to "Wakame-ka" and "Kowaba-shu". (Z)-3 -Hexen-1-ol, methyl 3-phenyl-2-propenoate, methyl jasmonate and indole were independent of the development of tea shoots and considered to be principle contributors to green tea flavor itself.