高γ-氨基丁酸茶游离氨基酸的变化及机理分析

本文对高γ-氨基丁酸（Gabaron）茶加工过程中离体茶鲜叶在无氧条件下游离氨基酸的变化进行了研究，结果表明：常规条件下的离体茶鲜叶游离氨基酸总量为2．5％，其中除含有一般的蛋白质氨基酸外，还含有茶叶特征氨基酸-茶氨酸（The）以及微量的γ-氨基丁酸等。游离氨基酸中含量较高的为谷氨酸（Glu）、脯氨酸（Pro）、天冬氨酸（Asp）、精氨酸（Arg）、组氨酸（His），较低的是苏氨酸（Thr）、丝氨酸（Ser）和甘氨酸（Gly）。离体茶鲜叶经3h无氧处理后，游离氨基酸总量达3．4％。其中Pro、γ-氨基丁酸（Gaba）、Gly、Ser、丙氨酸（Ala）、缬氨酸（Val）、Thr等游离氨基酸含量上升。Pro和Gaba是上升幅度最大的两种氨基酸，分别为正常条件下的3倍和15倍。无氧条件下Glu和ASP含量下降，降幅分别为45％、36％。其余游离氨基酸基本稳定不变。

Variations of Free Amino Acids during Processing Gabaron Tea and the Mechanism Analysis

The variations of free amino acids of excised tea leaves under anoxic stress were studied. The results showed that: The total content of free amino acids of excised tea fresh leaves is 2.5%. The Gabaron endemic amino acids of tea-theanine are determinated besides the normal protein amino acids. The free amino acids in high contents are Glu, Pro, Asp, Arg, His,while in low contents are Thr, Ser, Gly. The total content of free amino acids of excised tea leaves is raised to 3.4% after 3h anoxic state. The contents of Pro, Gaba, Gly, Ser, Ala, Val, Thr are increased with the contents of Pro and Gaba even 3 and 15 times higher than those in the normal condition respectively, but the contents of Glu with Asp are reduced, with the rates respectively 45% and 36%. The contents of the other amino acids are stable.