Phase Transition of Sunflower Oil as Affected by the Oxidation Level

The influence of the oxidation level on the phase transition behavior of sunflower oil was evaluated by differential scanning calorimetry (DSC) and synchrotron X‐ray diffraction (XRD) at both small and wide angles. The crystallization was monitored at a cooling/heating rate of 2 °C/min from 20 to −80 °C and vice versa applying both techniques. The triacylglycerols organize in two double‐chain length structures: α 2L (61.87 Å) and β′ 2L (82.89 Å). The crystalline structure changes upon oxidation. In particular, the intensity of the XRD peak associated with the double‐chain structure of β′, as well as its crystallization and melting enthalpy, significantly decreases as the oxidation level increases.