关键词: 茶叶加工, 绿茶, 滋味物质, 酚/氨比, 简单儿茶素/酯型儿茶素, 滋味品质

Abstract: Green tea was made from the one bud two leaves in spring of ‘Bixiangzao’ tree plants by spreading, fixation, rolling and drying processes. The dynamic changes in water extract content and the contents of taste substances in the water extract of green tea such as tea polyphenols, amino acid, caffeine, soluble sugar and catechins were analyzed during the processing of green tea and the ratio of phenol to ammonia, the ratio of non-esterified to esterified catechins and sensory quality were measured. The aim of this study was evaluate the impact of the dynamic changes in taste substances during green tea processing on its taste quality. The results showed that overall the contents of water extract and all taste compounds gradually declined during all processing stages, while the contents of water extract, amino acids, caffeine and soluble sugar increased during the spreading process. Correspondingly, the ratio of phenol to ammonia dropped from 11.45 to 6.21 at the spreading stage, then increased up to 8.01 at the fixation stage, and finally tended to stable at the rolling and drying stages. The ratio of non-esterified to esterified catechins increased from 0.43 to 0.45 at the spreading stage, followed by a decrease from 0.47 to 0.44 at the fixation stage, and then gradually declined to 0.35 at the rolling and drying stages. At the same time, these taste substances were significantly associated with the taste quality of green tea. When the phenol/ammonia ratio was in the range of 5.5–6.5, and the ratio of non-esterified to esterified catechins was 0.3–0.5, the taste quality of green tea turned from light and bitter to mellow and refreshing.

Key words: tea processing, green tea, taste substance, phenol/ammonia ratio, non-esterified/esterified catechins ratio, taste quality