Effect of processing conditions on yield and quality of hydraulically expressed palm oil

Abstract

Aninvestigation was carried out on the effect of processing conditions such as sterilization time, digestion time and expression pressure on the yield and quality of hydraulically ex- pressed crude palm oil. Palm fruits were collected, cleaned and sterilized for 30, 60 and 90 min. The fruits were then digested for 3, 5, and 10 min and later pressed with pressures of 0.5, 1 and 1.5 MPa for constant pressing time of 5 min. The results show that increase in sterilization time from 30 to 90 min, digestion time from 3 to 10 min and expression pressure from 0.5 to 1.5 MPa generally increa- sed oil yield. The highest yield of oil of 35% was obtained at the sterilization time of 60 min, digestion time of 10 min and expression pressure of 1 MPa. The solid impurity content of the oil (as a measure of crude palm oil quality) at 30 and 90 min steriliza- tion was observed to be generally high. The solid impurity at 60 min sterilization time was, however, observed to be low. Increase in digestion time and expression pressure increased the solid impurity at all sterilization times.