Effect of glycerol addition and heating rate on the thermal release behavior of cigar tobacco

Cigar is a kind of air-dried tobacco raw material with different physical structures and chemical compositions compared with flue-cured tobacco. The pyrolysis and thermal release characteristics of cigar tobacco are important for advancing their use in heat-not-burn cigarette. In this study, the thermal release behavior of cigar tobacco with different glycerol additions under heating conditions was analyzed by thermogravimetric technique as well as a self-built infrared rapid heating furnace combined with GC–MS analysis. The results showed that the thermal weight loss process of cigar tobacco could be divided into three stages. The addition of glycerol exhibited significant impact on pyrolysis process, especially in the stage II, accompanied by a decrease in T_max, an increase in DTG_max, and weight loss at this stage. Thermal release kinetic analysis of stage II by Coats-Redfern method showed an increased activation energy and pre-exponential factor. With the amount of glycerol addition increasing, the total aroma components released from cigar tobacco showed a trend of first increasing and then decreasing at both heating rates, and reached the highest level when the glycerol addition amount was 20%. By means of multi-factor analysis of variance, the significance of heating rate and glycerol addition as well as the optimum combination between them that could maximize the release of various types of aroma components was determined. This study may be beneficial for the reasonable utilization of cigar tobacco in related products.