Modification of Potato Pectin with Divergent Ultrasonic Treatment: Physicochemical, Microstructural, and Emulsifying Properties

In this study, the effects of different ultrasonic power densities (30, 40, and 50 W/L) and time (10, 20, and 30 min) on the physicochemical, microstructural, and emulsifying properties of potato pectin were investigated. The divergent ultrasonic treatment efficiently disrupted the side chain structure of potato pectin into smaller fragments, as well as the reduction of D50, D4,3, degree of methyl esterification (DM), degree of acetylation (DA), ζ-potential, and molecular weight (MW). The galacturonic acid (GalA, 38.87–70.14%) content was also increased. Subsequently, the emulsifying stability and uniformity of the droplet distributions for emulsions prepared with modified potato pectin were dramatically enhanced. Specifically, the turbiscan stability index (TSI) and physical stability of the emulsion prepared with potato pectin modified at 40 W/L for 20 min reached 6.96 and 44.66%, respectively, which were notably higher than those of unmodified potato pectin (22.39 and 39.00%).