不同类型难变黄烟叶烘烤特性研究

　　摘 要：以烤烟K326品种上部叶为试验材料，分别选取返青烟、高温逼熟烟、贪青晚熟烟3种类型难落黄烟叶进行烘烤，测定烘烤过程中烟叶的水分含量、外观颜色参数、叶绿素含量和多酚氧化酶活性等指标。研究结果显示：返青烟在变黄期和定色期失水较快，叶绿素降解量最高，多酚氧化酶活性波动较大；高温逼熟烟在变黄期失水最慢，叶绿素降解量中等，多酚氧化酶活性较低且变化较为平稳；贪青晚熟烟在变黄期和定色期失水较慢，叶绿素降解量最低，多酚氧化酶活性波动最大。研究得出：易烤性为返青烟>贪青晚熟烟>高温逼熟烟；耐烤性为高温逼熟烟>返青烟>贪青晚熟烟。
　　关键词：难变黄；烟叶素质；烘烤特性
　　中图分类号：S572 文献标识码：A DOI 编码：10.3969/j.issn.1006-6500.2017.08.018
　　Abstract： The upper leaves of flue-cured tobacco variety K326 were used as experimental materials， three types of tobacco leaves including re-greening leaves，heat-forced maturity leaves，over-green and late-maturing leaves were selected to bake. The moisture content， appearance color parameters， chlorophyll content and polyphenol oxidase activity were measured. The results showed that during yellowing and color fixing stage， re-greening leaves dehydrate faster， the degradation of chlorophyll was the highest， polyphenol oxidase activity fluctuations. Heat-forced maturity leaves water losing speed was the slowest， the chlorophyll degradation was medium， the polyphenol oxidase activity was low and the change was relatively stable. Over-green and late-maturing leaves slowly dehydrate， the degradation of chlorophyll was the lowest， the polyphenol oxidase activity has maximum fluctuation. It was concluded that for the easy curing potential，re-greening leaves were the best，over-green and late-maturing leaves were medium，heat-forced maturity leaves were the worst. And for the endurable curing potential， heat-forced maturity leaves were the best， re-greening leaves were medium， over-green and late-maturing leaves wee the worst.
　　Key words： hard to turn yellow；tobacco quality；curing characteristics
　　目前我國烟草生产对自然条件依赖性较强[1]，南方的土壤和气候更适于优质烟叶的种植。然而，近年来南方烟区在烤烟生长季节自然灾害频发，干旱和降雨分布不均等多重因素严重影响了烟叶正常的生长发育[2]。因大田期降雨过多、光照不均、肥效利用供应迟缓，造成部分烟叶出现返青、贪青晚熟、高温逼熟的现象，这些烟叶在田间难以成熟落黄，且在烘烤过程中变黄较难，但其难变黄原因不同，从而增加了烘烤难度和烟叶损失。吴锡刚等[3]研究了多种非正常烟叶的形成原因和相应烘烤技术，王贵等[4]以烟叶中水分含量为中心，研究了水分含量高烟叶和水分含量低烟叶的烘烤方法。但这些研究大都仅仅依据非正常烟叶的形成机理及鲜烟素质判定其烘烤特性并在烘烤过程中调整温湿度，通过探究非正常烟叶在烘烤过程中相关指标的变化来反映烟叶烘烤特性的区别较少。本研究以烤烟品种K326上部叶为试验材料，分析3类难变黄烟叶在烘烤过程中水分、颜色值、叶绿素、多酚氧化酶这些指标的变化，判定不同类型难变烟叶烘烤特性的区别，为难变黄烟叶烘烤可用性以及精准烘烤提供理论支持。
　　1 材料和方法
　　1.1 试验材料
　　供试材料为烤烟品种K326出现返青、贪青晚熟、高温逼熟现象的上部叶（第14～16位），烟株于2016年3月25号移栽，种植行距为120 cm，株距为50 cm，打顶后株高为110～120 cm。供试土壤为水稻土，前茬作物为水稻。在样品采集试验田测定土壤肥力，差异不显著（P>0.05）。
　　1.2 测定项目及方法
　　烘烤工艺采用常规三段式烘烤工艺[5]，烟叶水分测定采用 YC/T31—1996 法[6]，3种颜色参数采用霍开玲等的烤烟样品颜色测定方法[7]，叶绿素含量测定采用95%乙醇提取法[8]，多酚氧化酶活性用愈创木酚比色法[9]，烘烤特性参照 YC/T311—2009进行评价[10]。

相关热词搜索：烟叶 烘烤 不同类型 变黄 特性