This study was undertaken to investigate the effects of adding 0.1% (w/w)-0.9% (w/w) polyglycerol esters (PGE) on palm olein fractionation based on crystal nucleation, crystal growth and product quality aspects. Palm olein (IV 56) with PGE additives was subjected to crystallisation at a temperature of 13°C for 335 min. The crystal nucleation and its growth were monitored using focused beam reflectance measurement (FBRM) technique, during which the in-line changes of crystal size distribution during the process were analysed. The fractionated products were analysed for their iodine value (IV) and triacylglycerol (TAG) composition. The FBRM results showed that the PGE promoted crystal nucleation coupled with reduced formation of undesired large crystals during the crystallisation stage. The product analysis also showed that the PGE discouraged the formation of olein entrainment in the solid fraction but promoted the formation of 1, 3-dipalmitoyl-2-oleoyl-glycerol (POP) content in the solid fraction. In addition, PGE also slowed the formation of 1-palmitoyl-2,3-dioleoy-glycerol (POO). The optimal dosage that offered best performance was 0.3% (w/w) PGE which gave the most medium sized crystals and best palm mid fraction product with lowest IV and highest content of POP. These results implied that PGE is a nucleation enhancing and crystal growth retarding additive in palm olein crystallisation at 0.3% (w/w) dosage.

Palm-based Tibetan butter equivalent was developed and evaluated from formulation, rheology, texture to microstructure. Firstly, the compatibility of palm stearin and palm olein was ascertained. The formulations of palm-based Tibetan butter equivalent were then optimally developed using a combination of palm stearin (37.5%), palm olein (37.5%) and soybean oil (25%). These were found to contain high unsaturated fatty acids and analogous solid fat content (SFC) at varying temperatures. Moreover, the palm-based Tibetan butter equivalent (TBE) showed a shear-thinning behavior, a gel characteristic, good plasticity and comparable texture characteristics (such as hardness, adhesion, cohesiveness and elasticity) to traditional Tibetan butter (TB). Furthermore, as determined by polarized light microscopy (PLM) and confocal laser scanning microscopy (CLSM), the microstructures also showed a similar structure, thus further indicating that palm oil is a good candidate as a substitute in making Tibetan-style butter. Overall, the palm-based Tibetan butter equivalent was developed by physical technology and could assist in increasing the enjoyable population as well as addressing the challenge of resource shortage, geographical origin and season of production.