花香型金萱红茶加工过程中主要理化成分动态变化

Dynamic Changes of Main Components in Flowery Jinxuan Black Tea during Processing

在传统红茶工艺基础上增加晒青、摇青工序,对关键加工工序样品中茶多酚、儿茶素、咖啡碱、游离氨基酸、可溶性糖、黄酮、蛋白质的含量进行分析。结果表明,鲜叶至揉捻阶段,水浸出物含量呈上升趋势。茶多酚、可溶性糖与蛋白质含量在鲜叶中均是最高的,分别为21.68%、31.56 mg/g、22.65 mg/g。整个加工过程中,游离氨基酸含量相对稳定,茶多酚含量逐渐降低,蛋白质含量变化不规律。晒青与摇青茶样中黄酮含量较高且差异不显著,分别为153.36、148.99 mg/g。茶样中儿茶素类物质以酯型儿茶素为主,表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)含量最高,其次是表儿茶素没食子酸酯(epicatechin gallate,ECG)。鲜叶至摇青阶段,EGCG含量增加,摇青结束后,其含量逐渐减少。咖啡碱是主要的嘌呤生物碱成分,揉捻工序中含量最高(4.17%),鲜叶中含量最低(3.63%)。根据相关性分析可知,金萱红茶加工过程中主要理化成分之间具有一定的相关性。多元线性回归分析结果表明,加工过程中水浸出物含量的变化主要是由嘌呤生物碱含量的变化引起的。

On the basis of the conventional black tea processing technology,sunshine drying and shaking were added.The content of tea polyphenols,catechins,caffeine,free amino acids,soluble sugars,flavonoids,and proteins in the tea samples of key processes were analyzed.The results showed that the content of water extract increased from the fresh leaves to the stage of rolling.The content of tea polyphenols soluble sugars,and proteins,were the highest in fresh leaves,which were 21.68%,31.56 mg/g,and 22.65 mg/g,respectively.During the whole processing,the content of free amino acids was relatively stable;the content of tea polyphenols gradually decreased;and the content of protein changed irregularly.The content of flavonoids in the sun-dried tea sample and shaking tea sample were 153.36 mg/g and 148.99 mg/g,respectively.The main catechins in the tea samples were ester catechins,and epigallocatechin gallate(EGCG)had the highest content among catechins,followed by epicatechin gallate(ECG).The content of EGCG increased from fresh leaves to the shaking stage and then gradually decreased.Caffeine was the main component of purine alkaloids,with the highest content(4.17%)in the rolling process and the lowest content(3.63%)in fresh leaves.There were correlations between the main components in the processing of Jinxuan black tea.The multiple regression analysis results showed that changes in the content of the water extract during the processing were attributed to changes in the content of purine alkaloids.