关键词: 烤烟, 八大香型, 热重分析, 低温热解, 香味成分, 主成分分析

Abstract: To investigate the low⁃temperature pyrolysis characteristics and aroma release differences of eight aroma types of flue⁃cured tobacco during heating，eight aroma types of flue⁃cured tobacco from typical ecological regions（fresh⁃sweet aroma type，honey⁃sweet aroma type，alcohol⁃sweet aroma type，burnt⁃sweet and burnt aroma type，burnt⁃sweet and alcohol⁃sweet aroma type，fresh and honey⁃sweet aroma type，honey⁃sweet and burnt aroma type，woody and honey⁃sweet aroma type，numbered QT，MT，CT，JJ，JC，QM，MJ and MM，respectively）were selected as the research materials. Thermogravimetric analysis was adopted，combined with the self⁃built program temperature control heating platform，the flue gas capture device and the GC⁃MS instrument，to analyze the thermogravimetric characteristic parameters and the differences in species and contents of heat⁃released aroma components of the eight flavor types of flue⁃cured tobacco. The results showed that the thermogravimetric loss process of all eight aroma types of flue⁃cured tobacco was divided into three stages. In stage Ⅱ，the maximum weight loss temperature（T_max）was 199.1—210.9 ℃，the maximum weight loss rate（DTG_max）was 6.9—10.1%/min，and the weight loss rate was 19.7%—26.3%.The weight loss rate and DTG_max of JC tobacco leaves were the lowest，and the weight loss rate and DTG_max of CT，JJ，QM and QT tobacco leaves were relatively higher.A total of 118 aroma components were identified in the heat⁃released aroma traps of the eight aroma types of flue⁃cured tobacco，with the total content of 10 223.92—15 338.56 μg/g. Nitrogen heterocyclic compounds accounted for the largest proportion（44.70%—56.70%），while oxygen heterocyclic compounds accounted for 9.86%—16.73%.The release order of oxygen heterocyclic components was aroma MJ>JJ>QM>JC>CT>MT>QT>MM.Based on the distribution of heat release products combined with principal component analysis，a comprehensive evaluation function of aroma quality was established.The comprehensive score was ranked as MJ>QT>JC>QM>MT>CT>JJ>MM. In summary，there are significant differences in the characteristic parameters of the thermal weight loss stage Ⅱ of the eight flavor types of flue⁃cured tobacco. The weight loss rate and DTG_max of the fresh⁃sweet aroma type，alcohol⁃sweet type，burnt⁃sweet and burnt aroma type，and fresh and honey⁃sweet aroma type tobacco leaves are relatively higher，which can be preferentially selected in the screening of heated cigarette raw materials.It provides a reference for clarifying the heat release characteristics of the eight flavor types of flue⁃cured tobacco and optimizing of heated cigarette raw materials.

Key words: Flue?cured tobacco, Eight aroma type, Thermogravimetric analysis, Low temperature pyrolysis, Aroma components, Principal component analysis