Ultrasound-assisted esterification of enzymatic starch for fabrication of OSA starch/chitosan complex granule: A stabilizer for Pickering emulsion

In this paper, we optimized the esterification reaction of enzymatic starch by using ultrasonic, and then explored the physicochemical properties of chitosan and OSA starch complex granules. Rice starch, after enzymatic treatment, was subjected to esterification and ultrasonic to produce OSA rice starch. Then, chitosan was used to complex with OSA rice starch. The results indicated that simultaneous ultrasonication and esterification did not significantly enhance the damage to the crystalline structure of starch, and Raman spectroscopy showed a more uniform distribution of OSA groups. The zeta-potential and FT-IR showed chitosan and OSA starch complex mainly relied on electrostatic interaction. Enzyme treatment and ultrasonication can improve the thermal stability of the complex granules and the adsorption stability at the oil-water interface. The complex granules were used as Pickering emulsion stabilizers to obtain very large droplet sizes with excellent stability, which is an excellent Pickering emulsion stabilizer to expand the application of starch-based Pickering emulsions in the food industry in the future.