Effects of germination and ultrasound treatment on the thermodynamics, nutritional and structural quality of highland barley fractions

Current research investigates the effect of ultrasonication (US) (20/40/60 kHz, 220 W, 30 min), germination (65 °C, 6 h), and their combined treatment (US + G) on gamma-aminobutyric acid (GABA) enhancement and quality profile of barley flour and bran. The results showed the highest improvements in ultrasound-assisted germinated barley flour. GABA levels increased significantly, correlating with enhanced GAD and GABA-T enzyme activities. Similarly, TPC, TFC and antioxidant potential were improved, associated with upregulated expression of mPAL, mC3H, mCHS, and mC4H genes in WB and BB tissues, enhancing phenolics biosynthesis. Surface disruptions, increased porosity, and cellular disintegration were observed in ultrasonicated samples. XRD patterns showed significant molecular arrangements and increased amorphous regions in ultrasound-treated fractions. Furthermore, FTIR spectra reveal protein unfoldings in the amide I region, suggesting enhanced protein functionality in ultrasound-assisted germinated flour. Hence, ultrasound-assisted germination can be proposed as a sustainable approach for nutritional enhancement of barley fractions to improve their suitability for functional implications.