上部叶带茎烘烤水分迁移及形态结构变化

摘要

探讨烤烟上部叶带茎烘烤烟叶水分迁移特性及物理形态结构变化,为提高上部叶工业可用性提供参考.以云烟87上部烟叶为试验材料,利用低场核磁成像和扫描电镜等方法研究了烘烤过程烟叶的水分迁移、形态收缩、微观结构及烤后烟叶物理特性.结果表明,带茎烘烤茎秆的水分经主脉向叶片迁移,使叶片、主脉和整片叶含水率均显著高于不带茎烟叶,54℃后茎秆水分向烟叶迁移速率逐渐下降;54℃前带茎烟叶叶片厚度收缩率显著小于不带茎烟叶叶片,54℃后带茎烟叶叶片厚度收缩率显著大于不带茎烟叶叶片;烘烤过程带茎烟叶主脉直径收缩率显著小于不带茎烟叶主脉;叶片干燥后,不带茎烟叶叶片栅栏组织细胞结构变化程度小于带茎烟叶叶片;烤后烟叶单叶质量和叶片厚度表现为不带茎烟叶显著大于带茎烟叶,拉力、填充值和合梗率均表现为带茎烟叶显著大于不带茎烟叶.可见,上部叶带茎烘烤延缓烟叶的干燥,进而影响烟叶的形态收缩、微观结构和物理特性变化,其烤后烟叶的可用性得到一定程度的改善.%Study on the characteristics of moisture migration and physical morphological structure of tobacco upper leaves with stalks during curing,in order to provide reference for optimization of curing technology of tobacco upper leaves with stalks.The upper leaves of Yunyan-87 were used as experimental materials,the moisture migration,morphological shrinkage and microstructure of the tobacco leaves during curing and the physical characteristics of the cured tobacco leaves were studied by nuclear magnetic imaging and scanning electron microscope.The results showed that the moisture in the stalk transported to tobacco lamina through tobacco midrib during curing,which made the moisture content of tobacco lamina and tobacco midrib of tobacco leaves significantly higher than those of tobacco leaves without stalks.The moisture migration rate of the stalk decreased gradually after 54℃.The leaf thickness of tobacco leaves with stalks was significantly lower than those of tobacco upper leaves without stalk before 54℃,but was significantly higher after 54℃.The tobacco midrib diameter shrinkage rate of tobacco leaves with stalks was significantly lower than those of tobacco leaves without stalk during curing.Changes of palisade tissue cell structure of tobacco leaves with stalks were significantly greater than those of tobacco leaves without stalk after the lamina drying.The single leaf weight and leaf thickness of tobacco leaves cured with stalks were significantly lower than those tobacco leaves cured without stalk,whereas percentage of stem,filling value and tensile breaking strength of tobacco leaves cured with stalks were significantly higher than those tobacco leaves cured without stalk.It could be seen that the tobacco leaves curing with stalks mainly delayed the drying of tobacco leaves,which affected the changes of morphological shrinkage,microstructure,and physical properties of cured tobacco leaves,and the industrial availability of its cured tobacco leaves was improved to some extent.