烘焙工艺对铁观音茶叶内含物变化规律的影响

The influence of baking process on the inclusion changes of Tieguanyin tea

以铁观音毛茶为材料,采用均匀设计法设置试验方案,结合二次多项式和双重筛选逐步回归分析,研究烘焙工艺中温度、时间和摊叶厚度等因素对茶叶内含物的影响.结果表明,精制清香型铁观音在80℃、150 min、4.0 cm和99℃、120 min、5.5 cm的条件下处理,可使生化品质达到较高.对烘焙温度、烘焙时间和摊叶厚度3个自变量及茶叶生化品质、儿茶素品质指数和苦涩味指数、γ-氨基丁酸和茶氨酸含量5个因变量进行双重筛选逐步回归分析的结果表明:烘焙温度为主要影响因素,温度每上升1℃,儿茶素品质指数提高0.7424,儿茶素苦涩味指数提高0.0126;烘焙温度和时间对生化品质、γ-氨基丁酸和茶氨酸含量的影响呈负相关,即低温长时间烘焙有利于功能性氨基酸的富集.经计算,其优化烘焙工艺组合为:85℃、300 min、1.0 cm,此时茶叶中的γ-氨基丁酸含量为1.027 mg·g-1,茶氨酸含量为7.102 mg·g-1.

The relationship between the baking conditions and the inclusion changes of Tieguanyin tea was studied by the means of uniform design and double-screening stepwise regression （DSSR）.The involved baking conditions were baking temperature,baking time and thickness of tea.The results showed that,Fen-flavor Tieguanyin tea with high biochemical quality can be baked at 80 ℃ for 150 min with 4.0 cm thickness or at 99 ℃ for 120 min with 5.5 cm thickness.The data was analyzed by DSSR,which have 3 independent variables and 5 dependent variables.The analysis showed that,the baking temperature was the main influence factor;when temperature rose 1 ℃,the catechin quality index increased 0.7424,bitter index increased 0.0126.But baking temperature and baking time had a negative impact on the tea biochemical quality,the content of γ-aminobutyric acid and L-Theanine.The best baking condition was 85 ℃ for 300 min with 1.0 cm thickness to enrich the functional amino acids.After verification,the tea contains 1.027 mg · g-1 γ-aminobutyric acid and 7.102 mg · g-1 L-Theanine.