名优绿茶鲜叶摊放过程中主要生化成分的动态变化

以一芽一叶茶鲜叶为原料,进行连续摊放(水分78%～61%)处理,取不同含水率摊放叶,分别进行液氮速冻和冷冻干燥,测定茶多酚、儿茶素各组分、氨基酸及各游离组分、咖啡碱、叶绿素、维生素C及可溶性总糖等含量,研究茶鲜叶摊放过程中主要生化成分的动态变化。结果表明,随着摊放时间的增加,茶鲜叶中含水率下降逐渐加快,干物质质量下降;茶多酚和儿茶素总量呈现前期下降后期有所上升的趋势,酯型儿茶素总量逐渐下降,鲜叶和摊放叶中检测不到没食子酸儿茶素(GC);氨基酸总量呈上升趋势,不同游离组分呈现不同的变化趋势;咖啡碱和可溶性总糖含量呈逐渐上升趋势,叶绿素和维生素C含量呈逐渐下降趋势。摊放过程中茶鲜叶不同生化成分具有不同的动态变化规律,本研究为提高名优绿茶品质提供一定的理论基础。

Dynamic Change of Main Biochemical Components of Premium Green Tea Fresh Leaves during Spreading

By using of a leaf and a bud shoot as fresh tea leaves material,and spread continuously(78%～61%) ,spread leaves with different moisture content were fixed with liquid nitrogen and freeze-dried. then the contents of tea polyphenols and catechin components,total amino acids and free components,caffeine,total chlorophyll,Vc and total soluble sugar were determined to study the dynamic change of biochemical components of fresh tea leaves during spreading. Results showed that with increasing of spreading time,moisture content of fresh tea leaves decreased rapidly gradually,weight of dry substance decreased;contents of tea polyphenols and total catechins decreased at first and then increased during spreading,total esters-catechins decreased gradually,but GC could not be detected in fresh tea leaves and spread tea leaves,content of total amino acids increased,but different free amino acid have different changing trends during spreading;content of caffeine and total soluble sugar increased while total chlorophyll and Vc decreased gradually. Different biochemical components of fresh tea leaves changes in different rules during spreading. This study provides supplied some theory for improving the quality of premium green tea.