Encapsulation of Bromelain in Liposome

Bromelain has been used as a meat-tenderizing agent in food processing. To increase the availability of bromelain, microencapsulation into liposome was carried out by the dehydration and rehydration method. Small unilamellar vesicles prepared by sonication treatment showed higher encapsulation efficiency (EE) than by the French press method. In the preparation of liposome, the effect of pH and centrifugal force on EE was also investigated and it showed a higher EE at acidic pH than at alkaline pH with centrifugation at 80, 000$\times$g. The actual EEs except unencapsulated bromelain which bound on the outside surface of liposome by electrostatic interaction also were investigated, and the optimal EE was at pH 4.6, at 0.6 of a ratio of bromelain to phosholipid(18.2%, w/w). Release of bromelain from liposomes was stimulated as the temperature increased at neutral pH.