壳聚糖固定化单宁酶及其澄清绿茶汤的应用研究

以固定化单宁酶的酶活和活力回收为指标,筛选出壳聚糖海绵载体固定化单宁酶。与游离酶相比,固定化酶的最适反应pH向酸性偏移0.5,最适反应温度提高5℃;对金属离子和EDTA的稳定性均增强。固定化酶的半衰期也明显延长,4℃时半衰期由35.39h延长至324.25h,25℃时半衰期仍高达189.56h。分别以没食子酸甲酯溶液和绿茶汤为底物,经连续6批次酶促反应,固定化单宁酶的酶活保持稳定。经固定化单宁酶处理后,绿茶汤澄清度、贮存稳定性明显提高。

Immobilization of Tannase on Chitosan and Its Application in Clarification of Green Tea

The chitosan sponge was chosen to immobilize tannase by detecting total and recovered activity.The optimal pH dropped 0.5 units and the optimal reaction temperature increased 5℃ after immobilization.The enzyme showed higher stability as compared to the native enzyme against metal ions and EDTA.The half-life of enzyme was prolonged from 35.39 h to 324.25 h when stored at 4℃ and it reached 189.56 h when stored at 25℃.The activity of immobilized enzyme was durable after six consecutive reactions with methyl gallate solution or green tea extracts as a substrate.The clarity and stability of tea extract were obviously improved after enzymatic treatment.