4个等级内山六安瓜片茶叶氨基酸的组成及差异

使用HPLC检测了内山六安瓜片4个等级茶样氨基酸组成及其含量。从每个茶样皆测出18种氨基酸,其中茶氨酸、谷氨酸、天门冬氨酸、脯氨酸、酪氨酸和丝氨酸是主要成分,苏氨酸、赖氨酸、缬氨酸和甲硫氨酸含量较少。从特级、一级、二级至三级,游离氨基酸总量分别为(38.848±0.671)、(32.774±1.177)、(26.113±0.326)和(21.887±0.354)mg·g~(-1),茶氨酸分别占游离氨基酸总量的69.86%、69.71%、67.33%和60.20%。特级瓜片的谷氨酸含量分别超出一级、二级至三级含量的19.3%、37.4%和55.7%。根据滋味,将18种氨基酸分为6类:滋味相关类(天门冬氨酸、谷氨酸、精氨酸、茶氨酸)、鲜爽类(谷氨酸、甘氨酸、丙氨酸、脯氨酸、茶氨酸)、鲜味类(天门冬氨酸、谷氨酸)、甜味类(丝氨酸、甘氨酸、丙氨酸、脯氨酸)、芳香类(精氨酸、酪氨酸、缬氨酸、亮氨酸、苯丙氨酸、赖氨酸)和苦味类(组氨酸、精氨酸、缬氨酸、甲硫氨酸、异亮氨酸、亮氨酸、苯丙氨酸)。前3类分别占这4个等级茶样游离氨基酸的82.95%~88.69%、77.89%~85.00%和17.79%~19.52%;前3类的每个类型含量在特级、一级、二级至三级的含量显著递减。据此认为可尝试将氨基酸按滋味分类以便评判不同等级茶叶的氨基酸组成及其含量对茶汤鲜度的贡献率。还计算了每个等级瓜片18种氨基酸含量之间相关性,探讨了显著正相关的组数对茶汤滋味的协同增效及其在不同等级瓜片茶叶之间差异。

Similarities and differences in composition of amino acids in four grades of Liu'an Neishan Guapian tea

of the first category, the content of the top, the first, the second and the third grade significantly progressively decreased. Based on the results, the amino acids could be classified by tastes to judge the contribution rate of the composition and contents of amino acids to the freshness of tea soup. The correlation coefficients between eighteen amino acids in every grade of Guapian tea were calculated. Subsequently, the coordinating synergy and significant positive correlation on tea soup taste and the difference between the four grades were discussed.