Enzymatic Activity of Bromelain from Crude Extracts of Crown, Peels and Stem of Pineapples from Different Agro-ecological Zones of Thika Region, Kenya

Bromelain is an enzyme that has great commercial value and is of wide interest in the pharmaceutical, food, and cosmetics industries. In Kenya, large quantities of pineapple by-products are not well utilized although they can be a potential source for bromelain. The objectives of this study were to determine the levels of bromelain in crude extract of different parts of pineapples from different agro-ecological zones (AEZ) of Thika Region, Kenya. Following extraction, protein concentration and bromelain activity was estimated using standard methods. The activity of bromelain for the crown from the upper (UAEZ), mid (MAEZ) and lower (LAEZ) was 89.57, 101.34, 100.78 U/ml and the activity was significantly lower (p<0.05) in pineapples from UAEZ compared to that the other two zones. For peels, the bromelain activity (U/ml) of pineapple from UAEZ (88.79 U/ml) was significantly lower (p<0.05) than that from MAEZ (98.21 U/ml) and LAEZ (97.65 U/ml). The bromelain activity in the stems of pineapple from LAEZ (89.71 U/ml) was significantly higher (p<0.05) compared to those from MAEZ (85.73 U/ml) and UAEZ (82.27 U/ml). In conclusion, the study shows that pineapple by-products in Kenya can be a good source of bromelain, with higher levels of activity being observed in pineapples from the lower and mid-AEZ.