降解上部烟叶大分子物质的复合酶配制与条件优化

为降低上部烟叶中淀粉和蛋白质等大分子成分含量，提高其吸食品质，本研究在统一评价酶活力的基础上，选用4种酶制剂（淀粉酶IV、蛋白酶I、果胶酶I和纤维素酶II）配制复合酶制剂，采用单因素法和Box-Benhnken响应面分析法对影响酶解效果的复合酶量、缓冲液pH、含水量和酶解时间等因素进行优化。分析显示，4个因素对上部烟叶中淀粉和蛋白质降解率的影响顺序为：缓冲液pH > 酶解时间 > 含水量 > 复合酶量。响应面分析结果确定最优酶解条件为：复合酶量1.1单位（即淀粉酶IV 33 U/g烟叶，蛋白酶I 550 U/g烟叶，果胶酶I 220 U/g烟叶，纤维素酶II 220 U/g烟叶）、缓冲液pH 7.7、含水量54 %、酶解时间5.5 h，此时淀粉和蛋白质降解率分别为19.54%和20.03%。本研究中的复合酶制剂及酶解条件可以很好地结合于烟草打叶复烤工艺过程中，具有较好的应用前景。

Preparation of Multienzyme Complex and Condition Optimization for Degradation of Macromolecules in Upper Tobacco Leaves

To decrease the contents of starch and proteins in upper tobacco leaves, four types of enzyme (amylase IV, protease I, pectase I and cellulase Ⅱ) were selected to prepare a multienzyme complex (MEC). The effects of multienzyme complex content, buffer pH, moisture content and enzymatic hydrolysis time on degradation rate of starch and proteins were studied by single factor experiment and Box-Benhnken experimental design of the response surface methodology. The results of ANOVA and response surface analysis showed that, degradation of both starch and proteins was significantly influenced by the 4 factors in the order of:buffer pH > enzymatic hydrolysis time > moisture content > multienzyme complex content. The optimum enzymatic conditions at 40℃ were obtained as follows:multienzyme complex content of 1.1 unit (amylase IV 33 U/g, protease I 550 U/g, pectase I 220 U/g and cellulase Ⅱ 220 U/g), buffer pH 7.7, moisture content of 54%, and enzymatic hydrolysis time of 5.5 h. Under this condition, the degradation rate of starch and proteins were determined to be 19.54% and 20.03%. The optimized multienzyme complex and enzymolysis conditions could be promisingly applied to the threshing and redrying process of tobacco leaves.