Crystallization behavior and texture of trans-containing and trans-free palm oil based confectionery fats

De Graef V., Foubert I., Smith K.W, Cain F.W., Dewettinck K., Crystallization behavior and texture of trans-containing and trans-free palm oil based confectionery fats, Journal of Agricultural and Food Chemistry, 2007, 55(25), 10258-10265

The objective of this study was to gain insight into the role of trans fatty acids in determining the crystallization behavior and texture of palm-based confectionery fats. Therefore, the isothermal crystallization behavior of two series, each of three fats, one trans-containing and one trans-free, was examined by pNMR, DSC, and rheology. Furthermore, the hardness of these samples was examined at three different storage times at 10°C. All of the trans free samples showed a two-step crystallization at 10°C which is hypothesized to be an α-mediated β’ crystallization at 10°C which is hypothesized to be an α-mediated β’ crystallization for two of the samples and a fractionated crystallization in the β’ polymorph for the third, while the trans-containing fats crystallized in a single step, probably a direct β’ crystallization. The trans-containing fat series clearly crystallized faster than the trans-free fat series and also yielded higher hardness values at all storage times investigated. The presence of trans fatty acids seems to reduce the effect of compositional variations on the crystallization process. For the trans free fats, chemical composition was much more critical in determining the crystallization rate, the SFC, and the final hardness value.