为研究和明确定色期掉温阈值参数,提高烟叶烘烤质量,通过在定色前期和定色后期分别设置不同的掉温幅度(2、3、4℃)和持续时间(3、5 h)处理,与正常烘烤处理(CK)对比烤后烟叶的挂灰比例、经济性状、化学成分、香气成分含量和感官质量,并基于TOPSIS法对烟叶质量进行综合评价和排序,从而筛选出定色前期和定色后期合理的掉温阈值参数.结果表明:(1)定色期掉温使烟叶挂灰比例由 26.56%提升至 86.62%,上等烟比例由 71.73%减至 25.81%,烟叶均价由 24.43 元·kg-1 减至 15.04元·kg-1;(2)烟叶化学成分综合得分由 91.72 减至 64.29,感官质量得分由 76.65 减至 72.15,香气物质含量由 887.557 7 μg·kg-1增至 3 105.076 1 μg·kg-1;(3)TOPSIS综合评价结果显示,CK的烟叶综合质量最优,不同的掉温幅度和持续时间均会降低烟叶质量.定色前期低于(2℃,5h),定色后期低于(2℃,3h),可以作为烘烤过程中定色期掉温示警阈值参数,能够为促进烟叶质量提升和工艺优化提供理论依据.
To study and clarify the temperature drop threshold parameters during the color setting period,and improve the baking quality of tobacco leaves,this study compared the ash hanging ratio,economic characteristics,chemical composition,aroma content,and sensory quality of cured tobacco leaves with normal baking treatment(CK)by setting different temperature drop amplitudes(2℃,3℃4℃)and durations(3 h,5 h)in the early and late stages of color fixation,and comprehensively evaluated and ranked the qual-ity of tobacco leaves based on TOPSIS method.So as to screen out reasonable temperature drop threshold parameters for the early and late stages of color fixation.The results showed that:(1)the temperature drop during the fixed color period increased the proportion of tobacco leaves hanging ash from 26.56%to 86.62%,the proportion of top grade tobacco from 71.73%to 25.81%,and the average price of tobacco leaves decreased from 24.43 yuan·kg-1 to 15.04 yuan·kg-1;(2)The comprehensive score of chemical components in tobacco leaves decreased from 91.72 to 64.29,the sensory quality score decreased from 76.65 to 72.15,and the content of aroma substances increased from 887.557 7 μg·g-1 to 3 105.076 1 μg·g-1;(3)The TOPSIS comprehensive evaluation results showed that CK had the best comprehensive quality of tobacco leaves,and different temperature drop amplitudes and durations would reduce the qual-ity of tobacco leaves.The temperature in the early stage of color fixing is lower than(2℃,5h),and in the later stage of color fixing is lower than(2℃,3 h),which can be used as a threshold parameter for temperature drop warning during the color fixing period in the baking process,and can provide a theoretical basis for promoting the improvement of tobacco leaf quality and process optimization.