Effects of germination temperature on physicochemical properties and in vitro protein digestibility of oat flour (Avena sativa)

This study investigated how germination temperature influenced the physicochemical properties and in vitro protein digestibility of oat flour. Oats germinated at 25 °C exhibited greater degradation of lipids and carbohydrates, and enhanced free α-amino groups compared to those germinated at 15 and 20 °C. Fourier transform infrared spectroscopy revealed a protein structural shift from ordered structures to more hydrated, less ordered conformations, aligning with up to 40% greater protein digestibility in germinated relative to ungerminated oats. Oats germinated at 25 °C exhibited higher β-sheet and β-turn content and a 22% increase in gastric digestibility relative to lower-temperature germinated oats. Phytic acid content decreased by up to 23%, trypsin inhibitor activity declined by up to 14%, while total phenolic content increased up to 2.4-fold compared to ungerminated oats. Overall, germination enhanced protein accessibility and digestibility in oat flour, while germination temperature primarily influenced gastric digestion kinetics rather than final intestinal digestibility.