Effect of Lipid Removal on the Physicochemical, Functional, Rheological, and Amino Acid Profiles of Pearl Millet, Buckwheat, and Quinoa Flours

The present study investigates the effects of lipid removal on the physicochemical composition, color attributes, functional behavior, pasting properties, rheology, amino acid profiles, and in vitro protein digestibility of whole and defatted flours of common buckwheat, white quinoa and pearl millet. Defatting led to significant reductions in moisture (6.4%-8.9%) and fat content (78%-82%), accompanied by a notable increase in protein (19%-23%) and ash content (19%-29%) across all flour samples. Color analysis showed enhanced lightness and diminished yellowness following lipid extraction. Hydration properties, oil absorption, and foaming capacities improved upon defatting. Whole buckwheat flour exhibited the highest peak viscosity values, while whole quinoa flour displayed limited granule swelling. Rheological measurements indicated that defatting strengthened the viscoelastic properties of quinoa and buckwheat but decreased in pearl millet, reflecting grain-specific starch-protein-lipid interactions. Amino acid profiling showed notable enrichment of both essential and nonessential amino acids in defatted flours, with glutamic and aspartic acids being predominant. In vitro protein digestibility increased modestly (1.6%-2.1%) after defatting. FTIR analysis confirmed the removal of lipid-associated functional groups without altering the fundamental protein and carbohydrate structural features. The enhancement in these properties was primarily attributed to increased protein concentration and reduced lipid content, underscoring the potential of defatted pseudocereal and millet flours as stable, nutritionally enriched, and functionally versatile ingredients for developing value-added food formulations.