速溶绿茶酶促氧化工艺试验研究

Experimental Study on the Enzymatic Oxidation of Instant Green Tea

利用茶鲜叶制得的茶叶多酚氧化酶复合酶,开展速溶绿茶酶促氧化研究。以速溶绿茶中儿茶素转化率为指标,采用单因素试验,考察酶液浓度、底物浓度、p H值、温度和时间5个因素对速溶绿茶酶促氧化效果的影响,并通过正交试验法优化最佳酶促氧化条件。结果表明,速溶绿茶较优的酶促氧化条件为:酶促反应体系中茶叶复合酶浓度为2.0%,速溶绿茶浓度为0.5%,反应体系p H3.5,温度45℃,反应时间2.5 h。在此工艺参数下,儿茶素转化率为34.79%。速溶绿茶酶促氧化产物在265、300、380 nm和460 nm附近有最大吸收峰,与红茶中的茶色素吸收光谱一致。速溶绿茶酶促氧化产物中茶黄素含量达14.68%,显著高于红茶提取物。

The compound enzymes were prepared from fresh tea leaves,and instant green tea was enzymatic oxidized by the compound enzymes in this article. The oxidation degree of catechins in instant green tea was set as evaluation index,single factor experiment was used to analyze the influence of five factors including concentration of compound enzymes,concentration of substrate,p H,temperature and reaction time on the effect of enzymatic oxidation,and the best conditions of enzymatic oxidation were optimized by orthogonal test. The results showed that the optimal enzymatic oxidation conditions of instant green tea as follow:in the enzymatic reaction system,the concentration of compound enzymes was 2.0 %,concentration of substrate was 0.5 %,the p H of system was 3.5,the temperature was 45 ℃ and the reaction time was 2.5 h. Under the conditions,the oxidation degree of catechins was high to 34.79 %. There existed four maximum spectral absorption peaks at 265,300,380 nm and 460 nm in the enzymatic oxidation products of instant green tea,and that was similar to the absorption spectrum of tea pigment in black tea. The content of theaflavins in enzymatic oxidation products of instant green tea was high to 14.68 %,and it was higher than that of black tea extract.