烘烤过程中温湿度与烟叶淀粉含量及淀粉酶活性变化的关系

Relationships of Starch Content and Amylase Activity to Temperature and Humidity during Curing Process

采用两台KY-2型自控电烤箱研究了烘烤过程中不同温湿度和持续时间条件下烟叶淀粉酶活性和淀粉含量的变化关系。结果表明,淀粉酶活性变化出现两个高峰,即变黄的中后期和定色后期至干筋期,淀粉大量降解的温度范围为38～44℃,不同部位的烟叶具有相同的变化规律。因此,在烘烤实际操作中烟叶变黄起点温度的选择应为35℃,在42℃以前烘烤环境的干湿差增大到3℃(尤其是中部烟叶),42℃以后提高湿球温度,保持一定湿度(尤其是上部烟叶),44℃以前根据烟叶的变化情况适当延长调制时间以利于保持淀粉酶的活性,促进淀粉的降解。

The relationships of the changes of amylase activity and content of starch in tobacco leaves to temperature, humidity and duration during curing were studied with two KY-2 automatic electric-heated ovens. The results indicated that there were two peaks of amylase activity, one in the middle to late stage of yellowing and the other in the late stage of color fixing to stem drying stage, the majority of starch was degraded when the temperature was in the range of 38-44℃, the leaves of different stalk positions followed the same rule. Therefore, the temperature of yellowing stage should be started from 35℃, before it reached 42℃ the difference between dry and wet bulbs should be widened to 3℃ (especially for cutters), and then narrowed appropriately to maintain proper humidity (especially for upper leaf), the curing time should be suitably extended according to the changes of tobacco leaves when the temperature was below 44℃ to keep the activity of amylase and promote the degradation of starch.