Abstract

To avoid degradation in the stomach,the proteolytic enzyme bromelain must be encapsulated in glutaraldehyde-crosslinked chitosan (CGF) hydrogels, which can maintain the activity of bromelain until it reaches the intestine. In this study, we isolated bromelain by using ammoniumsulfate precipitation, dialysis, and anionic exchange chromatography with DEAE-cellulose resin. Bromelain fractions were collected from each purification step and specific activities were sequentially from increased in crude enzyme, ammonium sulfate, dialysis, and DEAE chromatography fractions (fraction numbers 58–71), which have fractions of23.90, 122.00, 125.48, and 195.20 U/mg, respectively.Bromelain fractions from the dialysis step were encapsulated in CGF matrixes by using a postloading method. CGF hydrogels had a crosslinking degree of 84.37% and swelling ratio of 76.60%.The dissolutionprofiles ofCGF-encapsulatedbromelain were tested in artificial stomach fluid andintestinalenvironments, and bromelain encapsulationefficiency following the postloading method was 96.29%. Interactions between the hydrogel and bromelainwere limited to the hydrogenbonds, and the proteolyticactivities of bromelainwere maintainedat 0.17 U/mL in the present artificial intestinal environment.

Key words: bromelain, purification, postloading encapsulation, crosslinked chitosan