Yearly changes in contents of chemical constituents in first flushes of tea [Camellia sinensis] cultivars
2006
Ikeda, N.(National Inst. of Vegetable and Tea Science, Shimada, Shizuoka (Japan)) | Horie, H. | Mukai, T. | Goto, T.
Various chemical constituents in tea shoots (leaves + young stems) contribute to the taste of tea. For example, tannin gives tea its bitterness and astringency, caffeine contributes to bitterness, and amino acids give tea a sweet and brothy taste. From 1992 to 1995, total nitrogen, total free amino acids, tannin, caffeine, six major amino acids, and ascorbic acid in first flushs of 36 tea cultivars were analyzed. Differences between cultivars or between years were significant at the l% level for all chemical contents analyzed. Data were subjected to analysis of the variance. Total variance was divided into genotypic variance (sigma v2), yearly variance (sigma y2) and error variance (sigma e2). Genotypic effects were large for caffeine, tannin and arginine contents, and yearly effects were large for glutamic acid content. In 1994, the first flushes were rich in total nitrogen, total free amino acids, arginine and theanine and were poor in tannin compared to those in other years. The differences in the contents of chemical various substance were considered to be the result of pruning after the first plucking season in 1993.
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