Comparative study of extraction, purification and estimation of bromelain from stem and fruit of pineapple plant

Abstract

Bromelain is a major proteinase, isolated from pineapple (Ananas com osus).เท the plant, bromelain is accumulated in the entire plant to different extent and properties depending on its source.The objective of present study was to compare the amount and activity of bromelain present in stem and fruit of the plant.Bromelain was isolated from stems and fruit of adult pineapple plants by buffered aqueous extraction.Purification of enzyme was done by centrifugation, salt precipitation technique, dialysis, ion-exchange chromatography and estimation by Lowry's method.Bromelain was assayed for its activity by hydrolysis of gelatin, represented by using gelatin digestion unit.The homogeneity of bromelain was confirmed by SDS-PAGE (sodium dodecylsulphate-polyacrylamide gel electrophoresis) analysis.It was found that stem bromelain had a better activity than fruit bromelain in gelatin digestion unit analysis.Moreover, ion exchange chromatography using diethylaminoethyl cellulose (DEAE) anion exchangers maintained the structural integrity of purified bromelain and thereby the product exhibited better proteolytic activity then crude extract.