To enhance the quality of tobacco leaves, the suitable conditions for the coordination of threshing, redrying with collaborative aging were investigated. Simple correlation analysis and one-way ANOVA were employed to analyze the effects of threshing and redrying parameters and aging time on the conventional chemical components of tobacco leaves. The results indicated that: (1) As the aging time (0-30 months) increased, the reducing sugar generally showed a fluctuating trend of first rising and then falling, the total sugar generally showed a trend of first decreasing and then fluctuating slightly, the total plant alkaloids showed no significant change, the total nitrogen generally showed an “M” shaped change trend, the potassium generally showed a slight trend of first stabilizing, then increasing, then decreasing, and then stabilizing, and the chlorine generally showed a trend of first stabilizing, then decreasing, and then increasing. The reducing sugar and potassium both reached their peak at 12 months, the total sugar and total nitrogen reached their trough at 18 months, and the chlorine reached its trough at 24 months. (2) The key parameter a1 of threshing and redrying mainly positively regulated the reducing sugar, total sugar, and chlorine, a2 mainly negatively regulated the total plant alkaloids and positively regulated the potassium, a3 mainly positively regulated the total sugar, and a4 mainly positively regulated the reducing sugar, total sugar, and negatively regulated the chlorine. The key parameters of threshing and redrying had no regulatory effect on the total nitrogen. The regulation of chlorine by the key parameters of threshing and redrying mainly occurred during the threshing and redrying stage, while the regulation of reducing sugar, total sugar, total plant alkaloids, and potassium continued into the aging process. The study effectively regulates the conventional chemical components of tobacco leaves by optimizing the parameters of leaf threshing and redrying, as well as the aging time. This significantly enhances the aroma and taste quality indicators of the tobacco leaves, while also improving their usability. It provides important technical guidance and application value for the tobacco industry.

[Objective] To clarify the quality difference in different parts of flue-cured tobacco leaves and to provide theoretical support for the selection of cutting methods in threshing and redrying procedures. [Methods] After removing 10cm petioles, each single leaf was evenly divided into 9 locations according to the “#” shape. The differences and characteristics of conventional chemical components and coordination indexes in different locations of leaves were analyzed, and on this basis, entropy-weight TOPSIS analysis and cluster analysis were conducted, so as to evaluate the comprehensive quality of different locations of tobacco leaves. Finally, the sensory quality of the samples was evaluated. [Results] (1) There were significant differences in chemical composition and coordination indexes between different locations of tobacco leaf; (2) Tobacco leaf can be divided into three parts: (I, III, IV, VI), (II, V, VII, IX) and VIII. On the whole, the quality of middle and upper edges of the leaf (I, III, IV, VI) was better, especially the middle edges, but the quality of the base was poor, and the base near the stem (VIII) was the worst in the whole leaf; (3) After tobacco leaf cutting, there are differences in sensory quality between different location combinations, the sensory quality of the middle and upper edges (I, III, IV, VI) of the leaf is the best, and the sensory quality of the leaf base near the stem (VIII) is the worst. [Conclusion] In conclusion, there are certain differences and similarities in the quality of tobacco leaf in different locations, the industrial availability and utilization rate of tobacco raw materials can be effectively improved by cutting. Considering the practical situation, it is more suitable to divide tobacco leaf into middle and upper edges and the rest for separate utilization.