Comparative study of the microencapsulation by complex coacervation of nisin in combination with an avocado antioxidant extract

Abstract

The objective of this study was to evaluate several conditions for complex coacervation to encapsulate a mixture of nisin, an antimicrobial peptide, and an antioxidant avocado peel extract. We evaluated the effects of three factors: two matrix-wall systems (collagen-alginate and collagen-pectin), two drying methods (freeze and spray drying) and two core dispersion systems (water in oil emulsion or in suspension). The final characteristics measured for each microencapsulation treatment were: encapsulation efficiency, encapsulation loading, encapsulation yield, Aw, and moisture. The core dispersion method (emulsified or not) and drying method (freeze or spray), as well as their interactions, were important factors in the final characteristics of the microencapsulation produced by complex coacervation. The interaction of the three factors only had an effect on moisture. The core dispersion factor had an effect on the encapsulation loading of both bioactives, whereas the drying method had an effect on Aw and encapsulation yield. Higher loading was obtained with non-emulsified core; higher encapsulation efficiency and yield were obtained through the combination of spray drying with emulsified core. Higher Aw, and moisture were obtained with the freeze drying method and emulsified core. The drying methods modified the final morphology, shape and structure of the microcapsules.The wide range of microcapsules produced by the combination of the three assessed factors may offer the food industry a wide range of option to deliver functional ingredients and meet various types of needs.