烟叶叶脉水分迁移干燥特性分析

Analysis for moisture migration and drying characteristics of flue-cured tobacco veins

  • 摘要: 目的探究烘烤过程中烟叶叶脉水分迁移干燥特性,为优化烘烤工艺提供理论依据.方法以K326中部叶为试验材料,研究采后烟叶主脉和支脉维管束示踪染液分布、水分迁移速率,以及烘烤过程中烟叶失水状况和形态变化.结果烟叶叶脉水分迁移由叶基主脉维管束出发,优先向最近支脉迁移,最终到达叶尖部;烟叶主脉维管束水分迁移速率由叶基向叶尖呈逐渐减小趋势,距离叶基越近的支脉维管束水分迁移速率越大,支脉维管束水分迁移速率大于主脉维管束水分迁移速率.烘烤过程中,烟叶由叶基至叶尖水含率基本呈减小趋势;烟叶主脉直径收缩率逐渐增大,烘烤至42℃前,靠近叶基部主脉直径收缩率较大,42℃后,靠近叶尖部主脉直径收缩率较大,叶基部与叶中部间的主脉直径收缩率最小.结论烟叶叶脉水分迁移影响烘烤过程中烟叶各部分水分及主脉形态变化,叶脉水分迁移特性与烘烤过程烟叶失水特性间的关系可为烟叶水分散失的调控及烘烤工艺优化提供参考.

     

    Abstract: ObjectiveMoisture migration and drying characteristics of tobacco leaf veins were explored to provide re-ference for the optimization of flue-curing process. MethodK326 middle leaves were used as test materials. Distribution of tracer dyeing liquor in vascular bundles and moisture migration ratio of tobacco leaf primary veins and branch veins were studied, dehydration and shape changes of tobacco leaves during curing were also analyzed. ResultMoisture of tobacco veins first migrated from primary vein vascular bundle of leaf base, preferentially accessed to the nearest branch veins, and reached the tip part. The moisture migration rate of tobacco primary vein vascular bundles decreased gradually from leaf base to leaf tip. Water migration rate of branch vein vascular bundles increased as it was closer to leaf base. Moisture migra-tion rate of primary vein vascular bundle was higher than that of branch vein vascular bundle. The moisture content in toba-cco leaf decreased during curing from leaf base to leaf tip, and diameter shrinkage rate of tobacco primary vein radually in-creased. The diameter shrinkage rate of primary vein near leaf base was larger before 42 ℃ than that near leaf tip, when the temperature was over 42 ℃, the condition was on the contrary. Diameter shrinkage rate of primary vein between leaf base and leaf tip was the smallest. ConclusionMoisture migration of tobacco vines affects the changes of water content and pri-mary vein shape of tobacco leaves during curing. The relation between migration characteristics and dehydration characteri-stics can provide reference for regulation of tobacco leaf moisture loss and flue-curing process optimization.

     

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