Effect of Processing Conditions on Yield of Screw Press Expressed Palm Oil

Abstract

Abstract: Investigations were carried out on the effect of processing conditions (sterilization time, digestion time and screw speed) on the efficiency a typical screw press machine. Palm fruits were collected, cleaned and sterilized for 30, 60 and 90 min; then digested for 4, 7 and 10 min and later pressed at a screw speed of 4, 10 and 16 rpm. The results show that increase in sterilization time and digestion time at optimum screw speed of 10 rpm generally increased the oil yield. The solid impurity content of the oil (as a measure of crude palm oil quality) at 30 and 90 min sterilization was observed to be generally high. The solid impurity at 60 min sterilization time was however observed to be low. Increase in digestion time increased the solid impurity at all sterilization times. The highest oil extraction ratio (OER) of 17.90% and oil extraction efficiency (OEE) of 79.56% were obtained at the sterilization time of 60 min, digestion time of 10 min and screw speed of 10 rpm. In processing operation of oil palm fruit, there is therefore the need to carefully select the processing conditions that will give the least solid impurity content of the oil as a measure of crude palm oil quality, highest oil yield and best oil quality.