Effect of Different Humidity at Key Temperature Points on the Quality of Tobacco Leaves During the Yellowing Period of Roasting of Upper Leaves
In order to determine the appropriate wet-bulb temperature at the key temperature point of the yellowing stage of the upper leave so flue-cured tobacco and improve the quality of the upper tobacco leaves,in 2022,the upper leaves of Yun-yan 87 were used as the material in Weijiatun Tobacco Science and Technology Park,Zhenyuan County,Guizhou Pro-vince,and different wet-bulb temperatures(35.5,36.0,36.5℃)were set at the key temperature point of 38℃during the yellowing period of roasting,and the changes of the main chemical components of tobacco leaves under different treatments and the quality of cured tobacco leaves were compared and analyzed.The results showed that the starch content decreased gradually,and the contents of total sugar and reducing sugar increased gradually,the total nitrogen and nicotine contents gradually decreased with the continuous advancement of the roasting process,but the decrease was small.The degradation rate of starch to total sugar in tobacco leaves under different humidity treatments was 36.5℃>36.0℃>35.5℃,there was no significant difference in nicotine and total nitrogen content among the tobacco leaves.Under the treatment of 36.5℃,more chemical composition of cured tobacco leaves met the requirements of the upper high-quality tobacco leaves,and the coordination of tobacco leaves was better,and the evaluation quality,appearance quality and grade quality were relatively high,while the quality indexes of tobacco leaves treated at 35.5℃were poor.Comprehensive analysis showed that it was more appropriate to bake the upper leaves of flue-cured tobacco at 36.5℃when the key temperature point turned yellow at 38℃.