Impact of germination on nutraceutical, functional and gluten free muffin making properties of Tartary buckwheat (Fagopyrum tataricum)

The influence of germination period (24–96h) on nutritional composition, antinutrients, free and bound polyphenols and muffin-making properties of Tartary buckwheat (TBW) flour was evaluated. The antioxidant activity of flour increased after germination for 72h due to more accumulation of free flavonoids and phenolic acids. Although free rutin was the main polyphenol, but the highest increment after germination was observed in kaempferol, catechins, vitexin and p-coumaric acid. TBW germination for 48–72h caused an increase in essential amino acids (lysine, leucine and phenylalanine) and GABA content of flour. Flour functionality in terms of water absorption and foaming capacity improved upon germination for 48h, though foaming stability declined upon germination. The incorporation of 24h–48h germinated TBW flour to rice-based batter decreased storage (G′) and viscous (G″) moduli; however, G′ and G″ increased with increased incorporation of TBW flour and these batters yielded muffins with the highest specific volume. Whereas, prolonged germination (96h) yielded exceptionally high G′ and G″ leading to a highly thick sticky batter that yielded muffins of lower specific volumes and higher firmness. The glycemic index of muffins incorporated with germinated (24–48h) TBW flour was lower than those made using ungerminated TBW. Prolonged germination for 96h increased the glycemic index of TBW incorporated muffins.