Tri-frequency ultrasonication priming enhances germination, nutritional quality and techno-functional properties of...

The current study explored the effect of multifrequency ultrasonication (20, 40, 60 kHz, and their combinations) on germination, nutritional profile, techno-functional properties, and physical properties of tartary buckwheat. Relative to the non-ultrasonicated control group, tri-frequency ultrasonication at 20/40/60 kHz significantly improved water absorption by 88.66 %, increasing immobilized and free water availability to achieve a germination rate of 85 % at 48 hrs. This ultrasonication-assisted germination increased α-amylase, PAL (phenylalanine ammonia-lyase), PPO (polyphenol oxidase), and POD (peroxidase) activities by 1.63, 6.84, 4.69, and 5.09 folds, respectively. This metabolic modification augmented phenolic accumulation and antioxidant capacity by 55.53 % and 14.60 %, respectively. Additionally, these enzymatic variations facilitated the phytic acid mitigation (45.21 %) and reduced tannin synthesis by 19.19 %. Ultrasonication-assisted germination improved the techno-functional properties of germinated tartary buckwheat flour, as indicated by elevated water holding capacity (35.86 %), water absorption index (48.28 %), water solubility index (30.62 %), emulsifying capacity (49.33 %), and emulsifying stability (24.33 %), compared to germinated control at 120 hrs. Furthermore, the texture profile was positively influenced, with hardness, gumminess, and chewiness reduced by 37.30 %, 42.82 %, and 51.35 %, respectively. Similarly, E-nose analysis revealed an improved aroma profile, characterized by augmented retention of sulfur compounds linked to a nutty, distinctive flour aroma. Therefore, tri-frequency ultrasonication emerges as a viable pretreatment for optimizing the nutritional quality and techno-functional quality of germinated tartary buckwheat flour.