红茶加工过程中纤维素酶和主要品质成分的动态变化

为探究红茶在日光萎凋、揉捻、发酵等加工工序中纤维素酶和主要品质成分的变化规律,本研究以凫早2号(C.sinensis cv.Fuzao2)为原料,测定红茶加工过程中β-葡萄糖苷酶、内切葡聚糖酶及外切葡聚糖酶的活性,同时分析了可溶性糖、儿茶素、咖啡碱、游离氨基酸等主要品质成分含量的动态变化。结果表明,β-葡萄糖苷酶活性、儿茶素总量、氨基酸总量在日光萎凋阶段结束后达到最高值,分别是0.091 U(10 min)-1·mL-1、97.6 mg/g、38.9315 mg/g,揉捻阶段迅速下降后趋于稳定;内切葡聚糖酶活性在日光萎凋开始至发酵结束呈持续上升趋势,从0.19 U(10 min)-1·mL-1增加至0.51 U(10 min)-1·mL-1;可溶性糖含量在揉捻、发酵期间下降迅速,而外切葡聚糖酶活性和咖啡碱含量在红茶加工过程中变化不显著。

Dynamic Changes of Cellulase and Main Quality Components in Processing of Black Tea

To study the changes of cellulase and main quality components during solar withering,rolling and fermentation of black tea,the fresh leaves of C. sinensis cv Fuzao2 as raw materials was used for manufacturing tea. The activity of β-glucosidase,endo-glucanase,exo-glucanase were detected,and the amount of main quality components such as soluble sugar,catechins,caffeine,free amino acids were also analyzed in processing of black tea. The results showed that the activity of β-glucosidase,the contents of catechins and free amino acids reached the highest level at the end of withering stage(0.091 U(10 min)-1·mL-1,97.6 mg/g,38.9315 mg/g),and decreased rapidly at rolling stage,then to be stable. Endoglucanase activity continued to increase from the onset of solar withering to the end of fermentation,increasing dramatically from 0.19 U(10 min)-1·mL-1 to 0.51 U(10 min)-1·mL-1. The contents of soluble sugar reduced remarkably at rolling and fermentation stage. However,the activity of exo-glucanase and the contents of caffeine had no significant changes during black tea processing.