Influence of Polyglycerol Ester Additive on Palm Oil Fractionation in Relation to the Crystal Size Distribution

Abstract

The effect of polyglycerol ester (PGEmix-8) additive on palm oil fractionation was studied at isothermal temperature of 24°C. Sampling was conducted at 20 min intervals to determine the solid fat content (SFC) of the slurries and the yield and compositions of the olein and stearin fractions. The peak of crystal size distribution was reduced from 100 μm to an average of 70 μm when 0.1% (w/w) to 0.5% (w/w) of PGEmix-8 were added in palm oil. The peak value was further reduced to 35 μm when 0.7% (w/w) additive was used. In spite of this, the SFC of the slurries remained unchanged during the isothermal crystallisation. These results show that PGEmix-8 had influenced the crystal size distribution without affecting the volume of the crystals formed. The fractionation results showed that olein yield increased about 3% to 6% but the triacylglycerol composition of the oleins were comparable with the control. An increase of saturation and a reduction of monounsaturation content in the stearin fractions were observed with increasing PGEmix-8 addition. These results implied that the increase in olein yield was due to less olein entrainment as a result of the more homogeneous and smaller crystals of the palm oil slurries.