Combined feeding strategy based on the physical properties of tobacco leaves for improving moisture stability during primary processing

Moisture fluctuations during tobacco primary processing can impair process stability and downstream product consistency. This study developed a combined feeding strategy for 27 tobacco grades in a fixed brand formulation by relating leaf microstructure, surface wettability, initial moisture content, and water absorption behavior. Surface and cross-sectional structures were characterized by scanning electron microscopy, wettability by water contact-angle measurements, and moisture content by the standard drying method. Surface pores were mainly round, oval, or rectangular, with sizes of 10–50 μm, and varied markedly among grades and origins. Cross-sections exhibited a gradient pore structure, with smaller, denser pores near the upper and lower surfaces and larger, looser pores in the interior. All samples were hydrophobic, with contact angles above 90°, although hydrophobicity differed among grades. Based on these characteristics, the 27 grades were classified by water absorption capability and used to establish a combined feeding mode. Under the investigated industrial conditions, this mode reduced the standard deviation of inlet moisture content from 0.48 to 0.30 %, a relative decrease of 37.5 %. Matching tobacco grades by initial moisture content and water absorption capability therefore improved moisture stability without altering the fixed formulation.