为探究不同产地珠形绿茶品质差异,采用密码审评法、色差法、高效液相色谱法及多元统计分析,比较3个主产地样品在感官品质、色泽及滋味化学成分组成方面的差异。结果表明,绿宝石的容重最大,干茶和茶汤色度a值最小,可溶性糖含量显著低于其他产地,而黄酮含量最高;涌溪火青和绿宝石的茶多酚、儿茶素含量相近,均显著高于平水日铸(P<0.05);3个产地绿茶水浸出物、氨基酸、咖啡碱的含量无显著差异(P>0.05)。主成分分析解释了珠形绿茶特征变量62.293%的方差信息,不同产地区分较为明显。偏最小二乘法判别分析鉴定出关键差异性成分8种:a(干茶)、b/a(干茶)、b(茶汤)、a(茶汤)、表没食子儿茶素没食子酸酯、总儿茶素、儿茶素没食子酸酯和表没食子酸儿茶素。
In order to explore the quality characteristics of bead-shaped green tea from diverse regions, the code review, chromatic aberration, HPLC and multivariate statistical analysis were used to compare the differences in sensory quality, color and taste chemical composition of samples from 3 main producing regions. Results showed that the unit weight of Lvbaoshi was the highest, while the a value of dry tea and tea liquor was the least. The soluble sugar content of Lvbaoshi was significantly lower than that of other producing regions, while the content of flavonoids was the highest. Besides, the levels of tea polyphenols and total catechins of Yongxi Huoqing and Lvbaoshi were similar, both of which were significantly higher than that of Pingshui Rizhu (P<0.05). The major chemical constituents including water extracts, total free amino acids and caffeine were observed to have slight difference (P>0.05) among different regions. The principal component analysis explained the variable information of different green tea samples (62.293% of the variance), showing comparatively distinct distribution of different producing regions. In addition, 8 key differential components were identified based on the partial least squares discriminant analysis, including a value (dry tea), b/a value (dry tea), a value (tea liquor) and b value (tea liquor), epigallocatechin gallate (EGCG), total catechins, catechingallate (CG) and epigallocatechin (EGC).
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