Determination of mesocarp mass for effective heating in microwave assisted sterilization and extraction (MASE) of oil palm fruits

Abstract

Determination of palm oil mesocarp mass for effective heating in microwave assisted sterilization and extraction (MASE) was investigated by measuring dielectric properties of the mesocarp. The dielectric properties of oil palm mesocarp were measured using PNA-L Network Analyzer (NA) model N5232A that was equipped with measurement control and data logging. The actual moisture con-tent was determined by standard method oven drying and compared with the predicted value reported by another researcher. Penetration depth (Dp) of the mesocarp which represent how deep the power carried by an electromagnetic wave can penetrate into the material was calculated using an established equation. The results indicated that the dielectric properties of solid surface oil palm mesocarp were comparable to previous research that was obtained at 11.93±4.55 and 4.37±1.62 of dielectric constant and dielectric loss, respectively. The dielectrics constant, ϵ’ slurry samples of oil palm mesocarp was measured for 80, 100, and 120g, which represented 56.42±6.61, 52.27±3.76 and 46.86±3.79, respectively. The influence of water in moist mesocarp samples had dielectric properties similar to those of liquid water. Microwave wavelength easily penetrated the sample weight loading at 80g and 100g with Dp of 16mm due to suitable sample bed thickness capable to absorb microwave energy then dissipate heat to the surrounding, which is responsible for the effectiveness in microwave heating.