Impact of processing treatments induced changes on little millet: Insights in nutritional, structural and metabolite...

Little millet (LM) is a nutrient dense and climate resilient grain. The effect of different processing treatments (roasting, pressure cooking, soaking, germination) was studied on nutritional, anti-nutritional, structural (SEM, XRD, texture), thermal (TGA) and metabolite (NMR) profile of LM. Roasting resulted in significant (p < 0.05) enhancement of iron content (2.65 ppm), soaking and roasting significantly (p < 0.05) reduced phytic acid content to 0.241 g/100 g and 0.311 g/100 g, respectively. Germination showed significant (p < 0.05) improvement in bio-functional attributes prior to digestion (antioxidants, flavonoid content and α-amylase and α-glucosidase inhibition activity in ½-diluted samples) and after in-vitro digestion (CUPRAC activity, TPC and TFC). Presence of metabolites (amino acids, fatty acids and polyphenols) was prominent in germinated LM. SEM of intact grain and flour revealed notable morphological changes in starch granules on processing. Roasting resulted in a damaged starch structure, while pressure cooking led to complete loss of starch morphology. Soaking and germination affirmed swollen starch granules. XRD revealed enhanced crystallinity in soaked and germinated LM. Reduced fracturability and hardness were observed after pressure cooking and germination. These inferences indicate potential of processing treatments in improving functionality and utility of LM in functional foods.