不同茶树品种碾茶的品质分析

以常用于制作抹茶的8个茶树品种鲜叶为原料制成碾茶,分析其在感官品质、理化成分和色差方面的差异,并对碾茶主要化学成分含量（比值）与其滋味属性评分进行Pearson’s线性相关分析,结合滋味贡献度Dot（Dose-over-threshold）值分析,以期明确碾茶中的主要滋味贡献物质,探究不同品种碾茶间滋味特征的差异性。结果表明,龙井43碾茶整体表现最佳,其外观色泽墨绿,有海苔香,茶汤滋味鲜爽,游离氨基酸总量和茶氨酸含量最高、酚氨比最低,叶绿素含量高;薮北和奥绿次之。相关性分析发现,碾茶的鲜味主要与游离氨基酸、咖啡碱、茶氨酸、天冬氨酸、天冬酰胺等含量及酯型/非酯型儿茶素比值呈显著正相关（P<0.05）。Dot值分析表明,EGCG和GCG是碾茶茶汤涩味主要贡献物质,咖啡碱、EGCG和GCG是苦味的主要贡献物质,且茶汤涩味和苦味都以EGCG为最主要的贡献因子,单个氨基酸组分对茶汤鲜味的贡献度较低（Dot<1）。

Quality Analysis of Tencha Made from Different Tea Cultivars

Fresh tea leaves of eight tea cultivars commonly used to make Matcha were used as materials to analyze their differences in sensory quality, physical and chemical composition and color of the processed Tencha. The main taste substances and the differences of taste characteristics of Tencha among different cultivars were clarified according to Pearson’s linear correlation analysis of the contents (ratio) of the main chemical components and its taste attribute score, together with the Dot（dose-over-threshold）value analysis of the taste contribution . The results show that Tencha of Longjing 43 had the best overall performance with green appearance, seaweed fragrance, umami taste of tea infusion, the highest contents of both free amino acids and theanine, the lowest phenol ammonia ratio, and high chlorophyll content. Yabukita and Kyomidori followed. Correlation analysis shows that the umami taste was positively correlated with the contents of free amino acids, caffeine, theanine, aspartic acid, asparagine and the ratio of ester catechins/non-ester catechins (P<0.05). Dot analysis shows that EGCG and GCG were the main contributors to astringency. Caffeine, EGCG and GCG were the main contributors to bitterness, and EGCG was the most important contributor to astringency and bitterness of the tea infusions. While single amino acids had low contributions to the umami taste of the tea infusions (Dot<1).