Processing-induced Modifications in Techno-functional Properties of Proso Millet (Panicum miliaceum L.) Flour

Abstract

Processing-induced structural transformations significantly influence the techno-functional properties of cereal flours by modifying hydration behaviour, particle interaction and packing characteristics. The present study investigated the impact of soaking, roasting, blanching, and germination on the flowability, hydration attributes, and lipid-binding capacity of proso millet (Panicum miliaceum L.) flour. Processing treatments resulted in measurable variations in physical parameters. Bulk density ranged from 0.52–0.57 g/cm³ and did not differ significantly among treatments (p = 0.678). In contrast tapped bulk density (0.70–0.77 g/cm³; p = 0.0033) showed significant variation, indicating changes in particle packing behaviour. Flowability indices were also affected, with Hausner ratio (1.10–1.44; p = 0.0349) and Carr’s index (21.47–30.04%; p = 0.0148), demonstrating significant differences, reflecting modifications in powder cohesiveness and interparticle interactions. Functional characteristics were similarly influenced by processing. Water absorption capacity increased (172.1–200.5%) significantly following roasting, indicating enhanced hydration potential. Oil absorption capacity (162.0–169.1%) remained statistically unchanged, suggesting relative stability of hydrophobic lipid-binding domains. In contrast, swelling capacity (77.75–87.55%) increased significantly after germination, indicating improved starch hydration and expansion. These changes are attributed to structural modifications within the flour matrix, including enzymatic hydrolysis during germination and partial starch gelatinization and protein denaturation during thermal processing. Overall, the findings demonstrate that targeted processing strategies can effectively modulate the techno-functional performance of proso millet flour, supporting its application in gluten-free and functional food systems.