Author:

Abstract:

Palm oil is one of the most consumed vegetable oils in the world because of its unique physical properties. It imparts a very high stability to the β’ crystal form, yielding relatively small crystals which give a smooth texture and due to its naturally balanced fatty acid composition palm oil is semi-solid at room temperature. As such, it forms an ideal hard stock to be used in trans free food products. However from a nutritional point of view, palm oil contains too much saturated fatty acids, since their presence in the diet is among the factors contributing to cardio-vascular diseases. When using more unsaturated fats as hard stock, minor components (including structuring agents like lecithin) can be added in order to avoid compromising the functionality of the food product. Therefore, industry’s interest in the use of emulsifiers as minor components in the production of edible fat products to give them desirable melting and crystallization properties is continuously increasing. The objective of this study was to investigate the influence of commercially available monoglycerides (M), polyglycerol esters (P) and lecithin (L) on the crystallization behavior of bulk fat as a function of the added concentration. Not only a single type of emulsifier, but also binary and ternary mixtures of M, P and L were added to the two different ‘host’ fats. The first was a palm based margarine fat, while the other was a non-hydrogenated vegetable fat, not based on palm oil which is used in fat rich products with a low amount of saturated fatty acids. A statistically sound mixture design was used to obtain as much information as possible. The obtained mixtures were analyzed for their non-isothermal crystallization and melting behavior by DSC. If a single type of emulsifier was added, the crystallization is accelerated due to heterogenous nucleation by adding M or P, while L addition has no significant effect on the crystallization rate. Furthermore it was shown that the minimum concentration necessary to provoke a crystallization accelerating effect is lower for P than for M. Antagonistic effects between M and L were suggested by the coefficient estimates of the special cubic model. When mixing the three emulsifiers a slight synergistic effect is observed, but the onset of crystallization is never higher than when pure M or P are added. When focusing on the melting behavior, emulsifiers (pure and in mixtures) reduce the offset of melting of both ‘host’ fats.