Effects of ultrasonic treatment and pH shift on the structure, functional properties and in vitro digestion of peanut protein

The growing demand for plant proteins has driven research into optimizing peanut protein extraction and functionality. This study investigated the influence of ultrasonic treatment and pH shift on peanut protein structure, functional properties and in vitro digestion. Results indicated that 30-min ultrasound improved peanut protein extraction rate and purity, while 15-30 min ultrasonic treatment at pH away from 4 reduced its mean particle size and improved its solubility, emulsifying and foaming properties. Additionally, 15-45 min ultrasonic treatment at pH 2-10 decreased peanut protein elastic modulus (G') and viscous modulus (G″) and increased its apparent viscosity. Moreover, 30-min ultrasound increased peanut protein digestibility and free amino content. Furthermore, ultrasonic treatment changed the peanut protein secondary and tertiary structure and decreased its relative crystallinity. By combining ultrasound and pH shifts, this study provides novel insights into optimizing peanut protein extraction and functionality, facilitating its broader application in the food industry.