PREPARATION AND CHARACTERIZATION OF MICROCAPSULES WITH OLEYL ACETATE ENCAPSULATED BY COMPLEX COACERVATION OF WHEY PROTEIN AND GUM ACACIA

Oleyl acetate,a component of insect sex pheromone,was synthesized using oleyl alcohol and acetic anhydride with oleyl alcohol/acetic anhydride molar ratio at 1/1.7 at 25℃ for 3 h,using 0.2% of p-toluenesulfonic acid as catalyst relative to the total amount of oleyl alcohol and acetic anhydride.Oleyl acetate was characterized using IR and 1H-NMR.Microcapsules containing oleyl acetate were prepared through complex coacervation of whey protein(WP)and gum acacia(GA).The coacervation process was optimized by varying experimental conditions such as pH,WP to GA ratio,wall materials concentration etc.It was observed that maximum complex coacervation yield could be achieved at wall concentration of 1.0%,and with WP/GA mass ratio of 1.5 at pH 3.5.Encapsulation of oleyl acetate using WP/GA as wall materials was carried out under the optimized experimental conditions.The loading and encapsulation rate of the core material were determined.It was found that the encapsulation rate increased with decrease in concentration of wall material.Morphology of microcapsules containing oleyl acetate was observed by scanning electron microscope.It revealed that the size of microcapsules was 5～8 μm,and the capsules possessed a core-shell structure with oleyl acetate encapsulated in the inner of the microcapsules.