黄金茶1号夏秋乌龙茶加工过程化学成分变化与品质形成分析

为研究黄金茶1号夏秋乌龙茶品质特征,以一芽三、四叶鲜叶为原料,采用固相微萃取结合气质联用(SPME/GC-MS)对挥发性成分进行测定,结合感官审评,分析其加工过程化学成分变化与品质形成。结果表明:干茶色泽青褐,汤色杏黄明亮,香气以清花香为主要特征,滋味醇和,叶底黄绿显红边。化学成分方面,从鲜叶到毛茶,茶多酚含量由16.82%降至11.61%,儿茶素总量下降了4.39%;游离氨基酸、可溶性糖总量呈波浪型变化;黄酮含量总体呈下降趋势;水浸出物含量萎凋后升高并达到最大值46.99%,最终毛茶含量为43.60%;(氨基酸+可溶性糖)/茶多酚比值毛茶最高,为0.97。加工过程共检出157种香气成分,其中醇类成分48种,碳氢类成分37种,酯类成分52种,醛类成分4种,酮类成分9种,其他类香气成分7种;其中α-法呢烯、反式-β-法呢烯和(Z,E)-α-法呢烯、芳樟醇、反式橙花叔醇、己酸己酯以及吲哚占到毛茶香气总量的69%以上,是黄金茶1号夏秋乌龙茶香气的主要组成部分。

Analysis of Chemical Components Changes and Quality Formation of Huangjincha 1 Summer Oolong Tea during Processing

In order to study the quality characteristics of Huangjincha 1 summer oolong tea,one bud,three and four leaves were used as raw materials. The solid-phase microextraction combined gas chromatography-mass spectrometer(SPME/GC-MS) was used to determine the volatile components. Combined with sensory evaluation,the changes of chemical components and quality formation of Huangjincha 1 summer oolong tea during processing were analyzed. The results showed that,Huangjincha 1 summer oolong tea had a light-brown color,tea soup was apricot and bright,and its aroma was mainly characterized by a fresh floral fragrance. The taste was mellow,and the infused leaves were yellow-green with red edge. In terms of chemical components,when the fresh leaves changed into oolong tea,the content of tea polyphenols decreased from 16.82% to 11.61%,and the total amount of catechins decreased by 4.39%,the total amount of amino acids and soluble sugars showed a wavy change,the contents of flavonoids decreased,the content of water extract increased and reached a maximum of 46.99% after the withering,the final content was 43.60%,and the ratio of(amino acid+soluble sugar)/tea polyphenol to the tea was the highest at 0.97. A total of 157 aroma components were detected during processing,including 48 alcohol components,37 hydrocarbon components,52 ester components,4 aldehyde components,9 ketone components,and 7 other aroma components. α-farnesene,trans-β-farnesene and(Z,E) -α-farnesene,linalool,trans-nerol,hexyl hexanoate and indole accounted for the total aroma of the oolong tea was more than 69% of the amount,which was the main component of the aroma of Huangjincha 1 summer oolong tea.