Effects of Leaf-threshing and Re-baking on the Conventional Chemical Components of Upper Tobacco Leaf

Purpose To investigate the dynamic effects of the leaf-threshing and re-baking processes on the conventional chemical components of upper tobacco leaves, providing a theoretical basis for optimizing re-baking parameters to improve tobacco quality.

Methods Using upper leaves of Yunnan-produced Golden Leaf tobacco as research material, changes in conventional chemical components were monitored throughout key processing sections, including primary conditioning, secondary conditioning, leaf-threshing, re-baking and drying, and dampening. Combined with variance analysis, correlation analysis, and principal component analysis (PCA), the regulatory effects of different process sections on total sugar, reducing sugar, nicotine, total nitrogen, petroleum ether extract, potassium ions, and chloride ions were systematically evaluated.

Results During the leaf-threshing and re-baking process, the content of each conventional chemical component showed a dynamic pattern of first increasing and then decreasing, peaking at the threshing section. After treatment of re-baking and drying, these indicators decreased significantly. Variance analysis showed that different processing sections had extremely significant regulatory effects on total sugar, nicotine, total nitrogen, potassium and petroleum ether extract (P<0.01), while chloride content did not fluctuate significantly during conditioning and re-baking sections. Correlation analysis revealed that the re-baking section was significantly or extremely significantly negatively correlated with the contents of total sugar, reducing sugar, nicotine, total nitrogen, and potassium. PCA further confirmed that the re-baking section had a more substantial effect on chemical components than the conditioning section, with drying treatment causing a sharp decline, while the dampening section only partially reversed these chemical changes.

Conclusions The re-baking section has a stronger effect on conventional chemical components of upper tobacco leaves than the conditioning section. It is recommended to focus on optimizing re-baking process parameters according to style requirements to improve tobacco quality. The results provide critical data support for enhancing the industrial usability of Yunnan-produced Gold Leaf upper tobacco leaves.