摘要：绿茶浸提液沉淀物中主要含有多酚。酚类物质和咖啡碱、蛋白质等大分子物质结合会造成茶溶液的冷后浑现象。沉淀物出现在绿茶浸提液中不仅影响产品外观，还会损害浸提液的口感和香气品质。其中主要与咖啡碱、蛋白质等结合的物质为酯型儿茶素表没食子儿茶素没食子酸酯（Epigallocatechin Gallate，EGCG）、表儿茶素没食子酸酯（Epicatechin Gallate，ECG），酯型儿茶素因为具有更多的没食子酰基和羟基，相较于非酯型儿茶素更倾向于形成沉淀。本研究通过在茶浸提液的澄清步骤中添加单宁酶来改善滋味并降低冷后浑现象，通过单因素实验与正交实验结合的方法，得出单宁酶降低绿茶浸提液沉淀率的最佳工艺。结论为：在30 ℃温度条件下，单宁酶添加量0.15%（质量分数），酶解60 min的最佳工艺，此时得到的绿茶酶解液苦涩味轻、回甘程度高、沉淀量低。综上，添加了单宁酶的绿茶浸提液具有更好的口感。本研究探索出单宁酶优化绿茶浸提液品质的最佳工艺，为获得高品质的绿茶浸提液产品，满足市场需求提供了新思路。

Green tea infusion sediments mainly contain polyphenols. The combination of phenolic substances, caffeine, proteins and other large molecules will cause the phenomenon of tea solution after cold muddy. Sediment in green tea infusion will not only affect the appearance of the product, but also damage the taste and aroma quality of the infusion. The main substances that bind to caffeine and proteins are the ester catechins EGCG and ECG, and the ester catechins have more galloyl and hydroxyl groups, which tend to form precipitates compared with the non-ester catechins. In this study, tannase was added to the clarification step of tea infusion to improve the taste and reduce the phenomenon of after-cooling turbidity, and the optimal process of tannase to reduce the precipitation rate of green tea infusion was concluded by combining a one-way experiment with an orthogonal experiment. The best process to optimize the green tea infusion was under the temperature of 30 ℃, the addition of tannase was 0.15%, and the enzymatic hydrolysis was carried out for 60 minutes, The obtained green tea enzymatic solution had light bitterness and astringency, high degree of sweetness and low sedimentation.In conclusion, the tea infusion with added tannase has better taste. This study explores the process of tannase to optimize the quality of green tea extract, which provides a new idea for high quality green tea extract products and market demand.