Effect of TAG composition on the crystallization behaviour of model fat blends with the same saturated fat content

In this study, the crystallization and polymorphic properties of eight fat blends with the same saturated fat content (50%) but with a varying TAG composition were investigated using DSC and X-ray diffraction. Blends were either palmitic (P) or stearic (S) based, and were all diluted with high oleic sunflower oil to obtain the same level of saturated fatty acids. Three different effects were investigated, namely the effect of chain length, the effect of trisaturated TAG and the effect of symmetry. The DSC results suggested that PPP, present in the palmitic based blends, seeded the crystallization process better than did SSS in the stearic based blends. Stop-and-return DSC revealed a two-step crystallization for almost all the blends at 15 °C, 20 °C and 25 °C. This behaviour was further elucidated by WAXD-analysis of the blends, showing an initial crystallization into an unstable polymorph followed by polymorphic transformation during crystallization.