Effect of Ultrasound-assisted pH Shift on Tartary Buckwheat Protein Structure and Functional Properties

This study investigates the effects of pH shift combined with ultrasound treatment on the structure and functional properties of tartary buckwheat protein. The results indicate that with ultrasound assistance and pH shift treatment significantly increased the free thiol content of tartary buckwheat protein (P < 0.05). This increase might attributed to protein unfolding, which exposed internal thiols or generated new thiols through disulfide bonds cleavage. When the ultrasonic time was 20 min and the ultrasonic power was 300 W, tartary buchwheat protein exhibited the highest surface hydrophobicity. This indicates that the protein underwent reorganization during the modification process, disrupting aggregates formed by hydrophobic interactions consequently, the protein particle size decreased, exposing more internal hydrophobic groups. In addition, the solubility of tartary buckwheat protein was significantly improved by ultrasonic assisted pH adjustment. Under alkaline pH conditions, the solubility was significantly increased from 63.85% to 103.48%. This treatment also significantly reduced the particle size of buckwheat protein (P<0.05), and enhanced its zeta potential and emulsifying activity (P<0.05). In summary, ultrasonic assisted pH adjustment effectively enhances the structural and functional properties of tartary buckwheat protein, and provides a new prospect for its application in the food industry.