To optimize the external L-glutamatic acid feeding conditions for increasing the yield of γ-aminobutyric acid in harvested tea leaves. A three factor-three level experiment design was developed by Box-Benhken central composite design method, in which the tea shoots were placed in test tubes with different concentration (m/V)L-glutamatic acid solutions previously adjusted to various pH value for operating time, then rinsing residual L-glutamatic acid out and blot up residual water of surface with filter paper. After that, the shoots were steamed 1 min at 80 ℃ ,then were frozen under -30 ℃for quantitative detection of γ-aminobutyric acid with paper electrophoresis-chromatography. By adopting response surface methodology, a second order quadratic equation was established, and the applicability of the model and interaction involved factors on predicting the yield of GABA was verified. The effects order of three factors on the yields of γ-aminobutyric acid were as follows: L-glutamatic acid mass concentration, soaking time and pH value of L-glutamatic acid solution. The optimal levels for achieving the highest yield of γ-aminobutyric acid were pH value of 4.8 and operation time of 5.5 h. The relation between L-glutamatic acid mass concentration in solution and the yield of γ-aminobutyric acid in tea is linear positive relevance, and whether or not linear correlation of them have nothing to do with pH value of solution and with soaking time, though they all can change the intercept of the linear model between the mass concentration and the yield. The intercept will reach the top value when all the pH and the time are optimal levels.%为提高茶叶γ-氨基丁酸(GABA)含量,优化谷氨酸溶液处理茶鲜叶的溶液浓度、pH值及浸渍时间等参数,以谷氨酸溶液处理茶鲜叶,按响应曲面法设计试验并建立二次多项数学模型,验证模型的有效性,响应面分析发现各因素对茶叶GABA含量变化影响的主次关系:谷氨酸溶液浓度＞浸渍时间＞pH值;茶叶富集GABA的最优水平为谷氨酸溶液浓度2.5%、pH 4.8、浸渍5.5 h.茶叶GABA含量与谷氨酸溶液浓度呈线性正相关;茶叶GABA含量与谷氨酸溶液浓度间是否呈线性变化与pH值和处理时间均无关,但后二者均可影响该线性关系的截距变化,且在它们的最优水平时有最大截距.
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