Structural and functional modulation of Fagopyrum tataricum by multifrequency ultrasonication, germination and...

The current study investigated the effect of multifrequency ultrasonication (MFUT), germination (G), soaking (S) and their combined effect treatments MFUT + G and MFUT + G + S on metabolite profile, structural modifications and techno-functional properties of Fagopyrum tataricum. Relative to the untreated native group, MFUT + G + S significantly (p < 0.05) outperformed individual treatments and MFUT + G. MFUT + G + S treatment increased PAL (phenylalanine ammonia-lyase), PPO (polyphenol oxidase), POD (peroxidase), and SOD (Superoxide dismutase) activities by 7.07, 9.60, 6.81, and 10.92 folds, respectively, while reduced tannins and phytic acid by 66.37 % and 60.07 %, respectively. These biochemical modifications enhanced polyphenolic accumulation (particularly chlorogenic acid, vanillic acid, syringic acid, rutin, and catechins), antioxidant activity and protein digestibility by 173.98 %, 284.89 %, and 102.21 %, respectively. FTIR and XRD confirmed structural modifications indicated by diminished starch crystallinity index (31.98-13.40 %) and α-helix (10.97-10.25 %) accompanied by enhanced β-sheets (20.71-35.83 %). Furthermore, MFUT + G + S exhibited reduced pasting properties and particle size, alongside increased surface hydrophobicity, zeta-potential and uniform particle dispersity. Collectively, these structural modifications enhanced water holding capacity (295.65 %), water absorption index (30.45 %), swelling power (35.94 %), emulsifying activity (68.04 %) and emulsifying stability (55.30 %) as well as superior thermal and textural stability. Furthermore, E-nose sensor response indicated an improved aroma pattern of MFUT + G + S. Collectively, these findings demonstrate that sequential application of MFUT and soaking pretreatments enhance both the functional quality and digestibility of germinated Fagopyrum tataricum flour.