The present work evaluated the effect of chemical interesterification on the crystallization properties of binary blends of hardfats from palm kernel (PKO), palm (PO), soybean (SO) and crambe oils (CR) with soybean oil (50:50 % w/w). The crystallization isotherm was obtained at 25°C by nuclear magnetic resonance spectrometer (BRUKER pc120 Minispec). The original Avrami equation was used to study the crystallization. Crystal morphology was examined by a polarized light microscope (Olympus, model BX 50) and the images were captured with ×20 magnification at 25ºC. The interesterification changed the curve shape of isotherms for all evaluated blends. Before the reaction, the curves were hyperbolic, after the reaction, however, the curves showed the characteristic sigmoid form of the Avrami model, in which crystallization occurs more slowly. Interesterification led to a decrease in SFCmax in all blends, an effect probably related to the reduction of trisaturated triacylglyderols and an increase in the dissaturated and monosaturated classes. The simple blends showed predominantly large spherulite crystals. Interesterification promoted significant reduction in crystalline diameter in all blends, as well as increased the number of crystals, which are now needle-shaped. This study demonstrated that chemical interesterification significantly modified the triacylglycerol pattern, and consequently the crystallization properties of the blends, for hardfats with different compositions.
