闷黄对黄茶品质形成的影响研究

Research on the Effect of Yellowing with Piling Process on the Quality of Yellow Tea

以沩山毛尖的加工工艺为参考,将闷黄分为六个阶段(1h、2h、3h、4h、5h、6h)进行取样,运用感官审评和理化分析相结合的方式对样品进行分析,得出以下结论:随着闷黄时间的延长,干茶色泽绿色减退,黄色显露,闷黄至5h后,汤色由绿明变成浅黄明亮,滋味鲜醇爽口,略带嫩香。在闷黄过程中,多酚类含量下降,氨基酸含量上升,闷堆5h左右,酚氨比值最小;可溶性蛋白质在闷黄过程缓慢下降,可溶性糖含量略有升高,水浸出物随着闷黄时间的延长含量稍有提升,叶绿素a,叶绿素b和总叶绿素在杀青和闷黄阶段降解损失较大,加工过程中还生成少量的TF。表明相同条件下,闷黄时间是影响黄茶滋味品质的主要因素之一,黄小茶闷黄时间以5h左右为宜。

Referring to the processing technique of Weishanmaojian,during the process of yellowing with piling, tea leaves were sampled out at the point of six phases（ 1h, 2h,3h,4h,Sh,6h, respectively）. They were assessed by the combination of approach of sensory evaluation and physical and chemical analysis. The results showed that with the prolongation of the duration of yellowing with piling, the color of tea leaves changed from green to yellow gradually.In particular, after 5h of yellowing with piling, the color of tea liquid changed from olivine to light yellow with brightness, moreover, the taste became delightfully fresh and mellow;during the whole process, the content of amino acid increased, while the counterpart of Polyphenols decreased with the least ratio of Phenol and ammo acid at 5h of yellow- ing with piling; soluble protein decreased slowly, and simultaneously, the content of soluble sugar rose a little bit. However, there is a comparatively large loss of Chlorophyll-a, Chlorophyll-b and total chlorophyll for the reason of degradation at the phase of Inactivation and Yellowing. Besides, small quantities of TF were also produced. In a word, a duration of 5 hours seems to be most suitable for yellow tea.