Effects of complex coacervation-spray drying and conventional spray drying on the quality of microencapsulated orange essential oil

Abstract

Orange essential oil (OEO) was microencapsulated by complex coacervation using a whey protein isolate (WPI)–arabic gum (AG) system followed by spray drying, and it was compared with the conventional spray drying microencapsulation process using N-Lok starch as wall material. Complex coacervation between WPI and AG was characterized in terms of zeta potential and coacervation efficiency. Coacervated microcapsules with different core:wall (OEO:WPI–AG) ratio (1:1–1:4) were spray dried using 160 and 90 °C as inlet and outlet temperature, respectively. Maltodextrin DE10 was added to protect integrity of coacervated microcapsules during spray drying. The highest retention and encapsulation efficiency (53 and 46% respectively) were obtained for a core:wall ratio of 1:2. The WPI:AG system with core:wall ratio of 1:2 was spray dried using 140–220 °C and 80–120 °C as inlet and outlet temperatures respectively, and the results indicated that these inlet and outlet temperatures had no significant effect on retention and encapsulation efficiency. Microencapsulation by conventional spray drying at 200–120 °C as inlet and outlet temperatures, resulted in the highest retention and encapsulation efficiencies (79 and 73% respectively), which represents 25% higher than spray dried coacervated microcapsules. After 4 months of storage, the spray dried coacervated microcapsules showed a tenfold higher carvone concentration (indicator of degradation), than the conventional microencapsulated spray dried product.