Physicochemical properties, non-nutrients and phenolic composition of germinated freeze-dried flours of foxtail millet, proso millet and common buckwheat

The grains of foxtail millet (FM), proso millet (PM) and common buckwheat (CBW) germinated over a period of 1–4 days were freeze-dried to better understand the changes in their chemical composition. The dynamic changes in the proximate, minerals, non-nutrients and bound and free polyphenolic profile of germinated freeze-dried grain flours of FM, PM and CBW was studied. Germination caused a remarkable decrease in crude fat and non-nutrients, while protein, reducing sugar and crude fibre increased for all three grains. Among non-nutrients, germination caused the highest decline in saponins followed by tannins and phytic acid, with CBW exhibiting greater loss than millets. HPLC analysis revealed higher free phenolic acids in germinated grains and a greater accumulation of rutin, quercetin and (+)-catechin was observed in CBW. Overall, the changes in nutrient composition were more pronounced in germinated freeze-dried flour of CBW than FM and PM. •Germinated CBW exhibited higher changes in nutrient composition than the millets.•Germination caused significant decline in saponin, tannin and phytic acid contents.•Protein, reducing sugar and crude fibre increased in germinated CBW, FM and PM.•Increase in level of free phenolic acids were more evident in germinated CBW (GD=4).•Accumulation of flavonols was higher in germinated CBW than FM and PM.