The effect of polyglycerol esters of fatty acids on the crystallization of palm olein

Abstract

This research investigated the effect of polyglycerol ester of fatty acids (PGE) on the crystallization of palm olein (POL). Three PGEs were studied: two solid-state PGEs (PGE1105 and PGE1117) and one liquid-state PGE (PGE1155). The addition of 0.5-5% wt. PGEs influenced the crystallization kinetics of POL and this depended on the type and concentration of the emulsifiers. During cooling down with a cooling rate of 5℃/min, the samples containing PGE1105 and PGE1117 started to crystallize at higher temperatures when compared with POL but the crystallization began at lower temperatures for the samples containing PGE1155. All samples with added PGEs exhibited lower solid fat content than that of POL after 12 h of crystallization time. The number of crystals decreased with an increase in the crystal size with PGE addition but there was no effect on polymorphism. Overall, the results suggested that PGE1105 and PGE1117 enhanced the early stages of POL crystallization possibly via the template effects but suppressed the later stages, whereas PGE1155 delayed the whole process of POL crystallization. The application of POL is often limited by its tendency to get cloudy at low temperatures during long-term storage. Based on the results, 1-5% wt. PGE1155 could be used to delay or prevent the crystallization of POL at low temperatures.