密集烘烤定色期升温速度对烤烟类胡萝卜素降解和颜色的影响

采用河南农业大学设计的电热式温湿自控密集烤烟箱,研究了密集烘烤定色期不同升温速度对烤烟类胡萝卜素降解组分、降解香气成分含量及颜色的影响.结果表明,类胡萝卜素含量随烘烤时间的推进逐渐降低,β-胡萝卜素、叶黄质、新黄质和紫黄质在定色期的降解幅度均为:慢速升温(1℃/2.0 h)>中速升温(1℃/1.5 h)>快速升温(1℃/1.0 h),慢速升温处理类胡萝卜素总量降幅达76.11%.烤后烟叶类胡萝卜素降解香气物质含量以慢速升温处理最高(39.73μg·g-1),其次为中速升温处理(35.07μg·g-1).烟叶各颜色参数在定色期开始后的18 h前后均有一个高峰,定色过程中亮度(L*)、红度值(a*)与烟叶类胡萝卜素及其各组分含量均呈负相关,其中a*与类胡萝卜素组分含量的相关性较好.可见,定色期以1℃/2.0 h升温利于烟叶类胡萝卜素的充分降解和外观质量及香气质量的改善.

Study on carotenoids degradation and color changes of flue-cured tobacco at leaf-drying stage during bulk curing

In order to improve the aroma quality of flue-cured tobacco and provide a theoretical basis for the optimization of curing technology,effects of the temperature-increasing rate at the leaf-drying stage during bulk-curing on the carotenoid degradation,content of the aroma components produced by carotenoid degradation and color change of tobacco leaves were studied.Results showed that: carotenoid content decreased gradually at the leaf-drying stage;the degradation degrees of β-carotene,lutein,neoxanthin and violaxthin were all in order: slow heating rate(T3)>medium heating rate(T2)>high heating rate(T1);the carotenoid degradation rate of T3 was the highest,i.e.76.11%.Content of the aroma components of T3 was the highest,reaching 39.73 μg·g-1,next was the T2,i.e.35.07 μg·g-1.The color parameters reached their peaks 18 h after the starting of leaf-drying stage.There were negative correlations between the color parameters of tobacco L*,a* and the contents of carotenoids as well as the other components,and there was a good correlation between a* and carotenoids contents.In general,heating rate of 1 ℃/2.0 h would benefit the sufficient degradation of carotenoids and improve the aroma and appearance quality of tobacco leaves at leaf-drying stage.