Ultrasonic modification of pectin for enhanced 2-furfurylthiol encapsulation: process optimization and mechanisms.

Pectin is an intriguing polymer that is usually considered as a byproduct from agricultural and biological processes. In previous studies, ultrasound treatment has been explored to improve the functionality of pectin, but most of the work focused on the aspects of molecular structure and chemical properties of pectin. In this study, we utilized ultrasound treatment to modify the physiochemical properties of pectin. Upon the ultrasound treatment, we evaluated the emulsifying capability of pectin, as a function of ultrasonic time and power density, using a response surface approach. Also, a very potent yet unstable coffee flavor compound, 2-furfurylthiol was used to compare the encapsulation feasibility of original pectin and ultrasound treated pectin.Our results showed that the particle size of pectin was highly correlated with power density and ultrasound time. Approximately 370 nm of pectin particle size could be reached at the power density of 1.06 W/ml for 40 min. Ultrasound treatment increased emulsion droplet size but significantly improved emulsifying capacities, such as centrifugal stability and surface loading, although it was highly dependent upon the ultrasound treatment condition. When used as the encapsulation wall material, the ultrasound modified pectin had significantly enhanced performance comparing to the original, in terms of the flavor retention over time at 45 °C and 65 °C.Ultrasound treatment was able to modify the physiochemical properties of pectin, which hence improved the emulsification stability and encapsulation feasibility by forming a thicker layer at the oil/water interface to protect the core materials. This article is protected by copyright. All rights reserved.