蒙顶山名茶游离氨基酸总量及组分的测定分析

Analysis of Free Amino Acid Content and Its Components in Various Mengding Tea

【目的】探讨蒙顶山名茶"鲜香"与"鲜味"特征的产生机制,提供蒙顶山名茶品质评价的理论依据。【方法】试验通过全量法和杯茶法制备茶汤试液,分别采用水合茚三酮比色法和L-8900型全自动氨基酸分析仪测定了4种蒙顶山名茶中的游离氨基酸总量和组分含量。【结果】4种蒙顶山名茶的游离氨基酸总量较高,分别为蒙顶黄芽(5.28±0.57)%,蒙顶石花(5.59±0.51)%,蒙顶甘露(4.65±0.82)%,蒙顶毛峰(5.34±0.96)%;在杯茶法1次冲泡5min条件下,蒙顶山名茶游离氨基酸的浸出率与浸出浓度亦较高,浸出率为55.24%～76.14%,浸出浓度为58.73～78.24mg/100mL;蒙顶山名茶游离氨基酸组分含量的特征为茶氨酸、天冬氨酸、谷氨酸、精氨酸和丝氨酸的含量在1 000mg/kg以上,色氨酸、半光氨酸、组氨酸和络氨酸组分含量为100～500mg/kg。【结论】蒙顶山名茶高氨基酸总量、丰富的组分含量及独特配比是其茶香"鲜香高长"、茶味"鲜浓爽口"的重要物质基础。

[Objective] This article aimed to find the potential physiological mechanism of the ＂deli- cious＂ and ＂flavor＂ feature in various kinds of Mengding famous tea, and further to provide theo- retical data for evaluating tea quality. [Method] Two methods with total extraction and brewing were used to prepare solution sample for determining free amino acid and its components, which were the content of free amino acid and its components were analyzed in four kinds of Mengding famous tea by the ninhydrin colorimetric method and the L-8900 type automatic amino acid analy- zer. [Results] Relative high contents of free amino acids were observed in the four Mengding fa- mous tea （Mengding Huangya （5.28±0.57） %, Mengding Shihua （5.59±0.51） %, Mengding Ganlu （4. 65±0. 82）% and Mengding Maofeng （5.34±0.96）%, respectively）. After brewing one time for 5 minutes, the extracting rate and content of free amino acid could he 55.24%±76.14% and 58. 73±78. 24 mg/L in Mengding famous tea. In addition, theanine, aspartate, glutamate, arginine and serine whose contents were more than 1000 mg/kg could be the dominant components of free amino acids in Mengding famous tea, although the contents of tryptophan, cysteine, histidine and tyrosine were ranged from 100 mg/kg to 500 mg/kg. [Conclusion] The results suggested that these four kinds of in- vestigated Mengding famous tea had rich free amino acid and reasonable components ratio, which could be the important basis for the feature of tea as ＂Lasting fresh fragrance＂ and ＂Fresh good tasty＂.