Enzymatic destruction kinetics of oil palm fruits by microwave sterilization

Abstract

Microwave sterilization of oil palm fruit is carried out to deactivate lipase and soften the fruits. This study is aims to determine enzymatic destruction kinetics from microwave sterilization of oil palm fruits such as decimal reduction time (D-value), temperature sensitivity (z-value), kinetic constant (k) and activation energy (Ea). Three power levels (medium, medium high and high) of the microwave oven were used and lipase assayed was conducted to determine the lipase activity. Microwave sterilization of oil palm fruits depends on the destruction kinetic parameters such as D-value, z-value and Ea. It required only 8.333 to 16.949 minutes to deactivate the lipase, and the process is not temperature sensitive which is indicated by z-value. The z-value indicated requirement to increase temperature up to 71.5, 77.0 and 83.0oC respectively from initial maximum temperature to reduce the D-value. Minimum energy required to start the destruction process of lipase was 13.927 to 14.049 kJ/mole obtained from microwave sterilization of 1 kg oil palm fruits at all power levels. Oil quality observed from free fatty acid (FFA) concentration that indicated FFA below 3.5%.