Optimization of Raw Material, Decolourizing Earth and Temperature Use in the Decolourization of Palm Oil

Abstract

The objective of this study was to evaluate the influence of raw material, decolourizing earth and temperature on the colour of bleached palm oil. Two types of decolourizing earth (American and Indian) were used. A four-factor centered composite response surface design was used to determine the effects of the different mentioned factors on the colour response of bleached palm oil at two DOBIs (2.3 and 1.3). The results obtained indicate that Indian earth with DOBI 2.3 oil has the colour variation contour lines at the high level of 16.0 red and at low level of 15.3 red. The decrease in colour around 15.4 is influenced by the effect of opposite temperature levels. The increase in color depends on the bleaching earth used. The temperature influences the colour of the bleached oil depending on the raw material. The bleaching temperature with American earth and a DOBI 1.3 oil, when it is at its high level (120°C) and at its low level (110°C), gives a colour of 15.8 red and 17.6 red, respectively. The optimal discoloration conditions (18.57 red) of CPO palm oil (P ≤ 0.05) are for American earth (with DOBI 1.3 oil): 92°C and 0.035% for temperature and percentage of phosphoric acid; 105°C and 0.6% for temperature and percentage of decolourizing earth. For Indian earth (with DOBI 2.3 oil), we have the optimum (18.66 red): 105°C and 0.035% for temperature and percentage of phosphoric acid; 118.5°C and 0.88% for temperature and percentage of decolourizing earth.