乳清蛋白/阿拉伯胶复凝聚法制备载乙酸油酯微胶囊及其表征

油醇(十八烯醇)与乙酸酐的摩尔比为1/1.7,催化剂对甲苯磺酸用量为油醇与乙酸酐总质量的0.2%,25℃反应3h合成了昆虫性激素成分之一的乙酸油酯并对其进行了表征.以高分子电解质乳清蛋白(WP)和阿拉伯胶(GA)进行复凝聚制备聚合物微胶囊,对影响复凝聚的pH、两种电解质的配比及其浓度等因素进行了考察.结果表明在pH=3.5,WP/GA质量比1.5,WP和GA总浓度1.0%时复凝聚效果最佳.在该条件下以WP/GA为壁材对乙酸油酯进行了包覆,制备了不同壁材总浓度的载油微胶囊,对微胶囊的载油量和包覆率进行了测量.随着壁材总浓度的增大,芯材乙酸油酯包覆率呈现先上升后下降的变化趋势.用扫描电镜观察,发现制备的载乙酸油酯微胶囊大小在5～8μm并且乙酸油酯以核壳式结构的形式被包覆在微胶囊内部.

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.