Effect of high coacervation temperature on the physicochemical properties of resultant microcapsules through induction of Maillard reaction between soybean protein isolate and chitosan

The mixture of soybean protein isolate-emulsified vitamin E emulsion and chitosan was incubated at 50 °C, 70 °C, and 90 °C for 12 h to check whether Maillard reaction could occur between the two polyelectrolytes during coacervation and its effects on the properties of resultant microcapsules. Color measurements and FTIR analysis revealed that Maillard reaction occurred during microencapsulation and was favored by higher coacervation temperatures. Coacervation at the three temperatures effectively reduced the aggregation and significantly increased the particle size and zeta potential of the microcapsules. The microencapsulation performance was promoted in higher temperatures and coacervation at 90 °C led to a yield of 89.15% compared with 56.30% of the control. Besides, the Maillard reaction-modified microcapsules exhibited better flowability, higher bulk density, and greater stability. It is concluded that the coacervation temperature is an important processing parameter to control the morphology and properties of microcapsules prepared by protein - polysaccharide coacervation.