Evaluation and multivariate analysis of antinutrients, bioactive and techno-functional attributes of finger millet and kodo millet as influenced by various germination regimes

Finger millet and kodo millet were germinated at different temperatures (25, 30, and 35 °C) and varying times (12, 24, 36, and 48 h), and changes in antinutritional, bioactive, techno-functional, molecular interactions, and morphology were evaluated. Germination of millets resulted in effective diminution of antinutrients, i.e., phytate content (PC) and condensed tannins (CT), with germinated kodo millet (48 h at 35 °C) exhibiting maximum reduction of 38.30% and 56.70% in PC and CT, respectively. The extractability of total phenolic content got improved by 35.10% and 57.10% for germinated finger millet and kodo millet, respectively; a similar trend was observed for antioxidant activity of both the millets. Prolonged germination at elevated temperature enhanced the oil absorption capacity, emulsifying and foaming attributes; while, adversely impacting the water absorption capacity of millets. Relative crystallinity of the millet starches incremented in initial 12 h of germination; thereby, exhibiting steady decline with extended germination period. Molecular interactions in amide-I region revealed that α-helix proportion exhibited reductions up to 28.00% and β-sheets and β-turns incremented by 39.00% after germination. Microstructural modifications with loosening of the starch-protein network and creation of crimpled starch matrix were observed for germinated millets. A positive correlation was observed amongst techno-functional and bioactive attributes; whereas, a strong negative correlation was detected between antinutrients and bioactive properties. The hierarchical cluster analysis revealed that germinated millets can be classified in 4-clusters based on treatment variations. The study suggested that germinated millets exhibited lower antinutrients with enhanced bioactive and techno-functional properties, suitable for producing extruded, weaning or baked products.