Effect of ethanol concentration on chemical composition of tobacco extracts
Ethanol is widely used as a solvent in the chemical, pharmaceutical, and biological industries, for the extraction of various natural products, including those from tobacco. In this study, an ethanol-water system with four different concentrations of ethanol was used for extracting products from flue-cured tobacco by reflux. Changes of chemical composition including the volatile compounds in the extracted fractions were measured. The extracts were also blended into a typical flue-cured cigarette tobacco blend for sensory evaluation. With the decrease of ethanol concentration, the following results were observed: 1) content of total sugar and reducing sugar in tobacco extracts gradually increased; 2) total alkaloids gradually decreased, and total nitrogen gradually increased; 3) range changes in total alkaloids and total nitrogen were smaller; and, 4) tobacco extracts of volatile alcohols, aldehydes, ketones, and esters were gradually reduced. With this system, the extraction can be effectively controlled according to the needs of cigarette formulations. It was found that tobacco extract with a high concentration of ethanol had a stronger effect on the top notes of cigarette tobacco blends and tobacco extract with a moderate and low-concentration of ethanol had a stronger effect on the body-base notes of cigarette tobacco blends. The developed technology can be used to improve the sensory quality of cigarettes by effectively modifying their flavour and taste. The requirements of the related cigarette tobacco blend for improving the formulation of the top notes, the body notes, and the base notes can be satisfied.