Bromelain Activity of Waste Parts of Two Pineapple Varieties

Abstract

Bromelain, a protease found in pineapples, is of high demand in the pharmaceutical, cosmetic and food industries. Along the pineapple processing chain, waste products such as peels, crowns, stems and cores result. These parts are usually discarded, though they contain significant amounts of the enzyme bromelain. This study sought to determine the bromelain activity of the crowns and peels of two pineapple varieties grown in Ghana; MD2 and Sugarloaf . The crude extract was obtained by homogenising the peels and crowns in a cold phosphate buffer and centrifuging at 3000 rpm for 15 min. Ethanol and ammonium sulphate precipitation were carried out on the extract between 30% – 80% precipitation levels. The enzyme activity was determined using the casein digestion method. Results showed that bromelain was precipitated mainly in the 30% – 60% precipitation range. Sugarloaf crowns yielded the highest enzyme activity of 20.82 U/ml and a specific activity of 194.58 U/mg at the 40% ammonium sulphate precipitation level. This was followed by the Sugarloaf peels with an enzyme activity of 19.98 U/ml at 50% ethanol precipitation level. Ethanol precipitation resulted in fractions with lower bromelain activity. Enzyme activity was higher in the Sugarloaf variety and also in the crowns of both varieties. The two pineapple varieties have significant levels of bromelain activity and could be exploited for commercialisation.