Three-stage roasting process of flue-cured tobacco in tobacco leaf dryer

Tobacco farmers often say, "Flue-cured tobacco is a treasure in the fire. It is a treasure when it is roasted well, and it is like dung grass when it is not roasted well." This vividly illustrates the close relationship between roasting and the quality of tobacco leaves. For fresh tobacco leaves, curing has four functions, one is to form the appearance quality of the tobacco leaves; the other is to form the chemical quality of the tobacco leaves; the third is to form the physical quality of the tobacco leaves; It can be seen that roasting is a key link in forming the quality of tobacco leaves. 1. Form the appearance quality of tobacco leaves The appearance quality of tobacco leaves refers to the quality factors that people can judge through the senses, usually judged by the way of seeing, touching, hearing and smelling. Appearance quality factors closely related to baking mainly include color, chroma, oil content, identity, injury and damage, six aspects. 2. The chemical quality of the tobacco leaves The chemical quality of tobacco leaves is an internal factor that determines the quality of smoke and the use value of tobacco leaves, and to a large extent determines the economic value of tobacco leaves. The chemical composition of tobacco leaves is closely related to the quality of tobacco products. The chemical composition of tobacco leaves is divided into two categories: organic compounds and inorganic compounds. Organic compounds: one is carbohydrates (containing three elements c, h, o), such as total sugar, starch, cellulose, etc.; the other is nitrogen-containing compounds (containing four elements c, h, o, n) , such as protein, amino acid, etc. Inorganic compounds: such as cl, k, mg, s, ca, and other inorganic salts. 3. Forming the physical quality of tobacco leaves The physical quality of tobacco leaves mainly includes flammability, hygroscopicity, elasticity, filling, weight per unit area, and stalk content, which refers to some physical properties of tobacco leaves in the process of cigarette cigarettes. 4. Evaluation of smoking quality of formed tobacco leaves During the curing process of tobacco leaves, in the yellowing stage, a series of macromolecular substances are decomposed into small molecular substances, forming the original aroma substances of tobacco leaves; in the color fixing stage, the original aroma substances are dehydrated and condensed to form aroma substances; The aroma substances decompose and volatilize, especially when baking at a high temperature above 68 °C, the aroma substances volatilize more. The whole tobacco leaf curing process fixes, presents and improves the quality of fresh tobacco leaves, forming a comprehensive evaluation of the smoking quality of first-cured tobacco leaves.