Investigation of the effect of time and temperature on crystallization of refined bleached and deodorized palm oil

Abstract

Crude palm oil is refined to remove the impurities in it and then bleached to degrade its colour so that it’s safe for consumption. After bleaching the crude palm oil, it's then deodorized to remove the volatile matter in the oil including the free fatty acids, odor and moisture. The palm oil which has been refined, bleached and deodorized is called Refined Bleached and Deodorized Palm Oil (RBDPO). This oil contains the olein which is oleic acid and stearin which is stearic acid as the major components which are separated by crystallization followed by dry fractionation using a membrane filter to produce the filtrate olein which is oleic acid and the residue stearin which is stearic acid having a higher melting point. The RBDPO sample was obtained from Mukwano Industries Ltd in Kampala District. Here the effect of time and temperature during the crystallization of RBDPO is investigated by cooling known amounts of RBDPO samples at lower and higher temperatures that is to 12°C and 22°C for the same amount of time and then determining the percentage yields of olein and stearin after each recommended interval. The cloud points of olein filtrates are also determined after dry fractionation which is followed by filtration. Different samples of known amounts of RBDPO are also cooled rapidly and gradually for the same amount of time although they are cooled separately for gradual cooling and rapid cooling. The percentage yields of stearin and olein for the samples from rapid cooling and gradual cooling are determined separately and then compared. The cloud points of olein filtrates are also determined. By carrying out the above experiments the effect of time and temperature during crystallization of RBDPO is evaluated from the percentage yields of olein, stearin and cloud points of the resultant filtrates.