Changes in the Physical and Chemical Properties of Tobacco during the Artificial Aging Process

This study was conducted to investigate the changes in various physical and chemical indicators during the aging process of tobacco, and provide reference for the development of quantitative evaluation methods for the degree of tobacco aging. Five types of tobacco leaves from different production area and stalk position were used as experimental objects, which were cut into tobacco shreds and aged for 385 days at 30 ℃ and 60% relative humidity with regular sampling. The color value (h, s, v, R, G, B, L, a, b), conventional chemical components (total sugar, reducing sugar, total nitrogen, nicotine, the ratio of reducing sugar to total sugar, the ratio of total nitrogen to nicotine), volatile acid, polyphenols, carotenoid content, absorbance values and pH of the tobacco leaves were measured, and the changes of each indicators during the aging process were analyzed. The results showed that as the follows. (1) Carotenoids, volatile acids, absorbance, color value G, and color value L changed by −54%, +43%, +28%, −29%, and −25%, respectively after aging for 385 days at 30 ℃ and 60% humidity (equivalent to 3-4 years of natural aging based on accumulated temperature), indicating a relatively large range of changes. (2) Among the indicators, except for the color indicator a, the linear regression equations of the remaining indicators with aging time reached a highly significant level (p<0.01), showing a good linear relationship with the tobacco aging degree. In conclusion, carotenoids, volatile acids, absorbance, color value G, and color value L are suitable as quantitative evaluation indicators for the aging degree of tobacco leaves.