乌龙茶做青过程中果胶酶活性及相关生化成分的动态变化

The Dynamic Variation of Polygalacturonase Activity and Related Biochemical Components during Rotation (Zuo-Qing ) Course of Oolong Tea

为了探明乌龙茶做青过程中果胶酶活性及相关生化成分的变化规律,选用金萱、白叶单枞的新梢,设置了新工艺摇青和在新工艺基础上加大强度摇青2个处理,并以在制品的不摇青处理作为新工艺的对照,研究了各处理过程在制品的果胶酶(PG)活性动态变化,同时,研究了Ca2+处理对PG活性的影响,并结合相关生化成分的变化探讨了PG在做青过程中对乌龙茶品质形成的生化效应.结果表明,茶鲜叶晒青后,PG活性明显上升,并在摇青期间的一摇或二摇后PG活性达到峰值;在新工艺基础上加大强度摇青,PG活性逐步下降,摇青处理的PG活性明显高于不摇青处理;Ca2+能显著抑制PG活性,PG活性变化与可溶性糖含量消长有密切联系.

In this trial, fresh leaves of two tea varieties named Jinxuan and Baiyedancong were selected, and were treated with new technics.Two contrasts were made, namely, when fresh leaves were withered under sunlight for 15～30 minutes, they were treated with no shaking operation and were made as contrast No.1.Shaking processed tea leaves 2 times by means of new technics,finished and took this as contrast No.2.Then dynamic variation of polygalacturonase activity and soluble sugar contents of 3 treatments abovementioned was studied besides,the effects of calcium ion on PG activity were researched. Results showed that from withering to the 1st or 2nd shaking, PG activity kept increasing, but after that it decreased gradually. There were obvious variance of PG activity between new technics and no shaking treatment. Soluble sugar contents have significant linear correlation with PG activity (p<0.05). Calcium ion can inhibit PG activity significantly. So utilizing and controlling PG activity properly will help gain better aroma and taste character of Oolong tea.