Phase Transition of Sunflower Oil as Affected by the Oxidation Level

Abstract

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: a 2L (61.87 Å ) and b 0 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 b 0 , as well as its crystallization and melting enthalpy, significantly decreases as the oxidation level increases.

Effect of the structure of monoglyceride–oil–water gels on aroma partition

“…These bumps are associated with the short-range organization of the triacylglycerol molecules of the liquid sunflower oil. These results are in agreement with data reported by Calligaris, Arrighetti, Barba, and Nicoli (2008) on the phase transition behaviour of bulk sunflower oil. These authors observed two broad peaks at similar interplanar distances associated to the diffraction of the liquid oil.…”

DSC evaluation of extra virgin olive oil stability under accelerated oxidative test: effect of fatty acid composition and phenol contents

“…All these changes may be related to the formation of lipid oxidation products that could form mixed and disordered triglyceride crystals. These crystals require lower energy to crystallize, and also retard the phase transition 30 . All these phenomena were also evident for EvooB and EvooC with the exception of T on , which shifted towards higher temperature at the end of storage.…”

Insights into the physicochemical properties of coffee oil

“…The two levels of organisation are easily identifiable from the short and long spacing observed by XRD at wide (WAXD) and small angle (SAXD), respectively. In particular, the use of synchrotron radiation, which provides an X-ray flux 10 3 -10 6 times more intense than that generated by usual X-ray sources, allows step-by-step recordings as a function of temperature [17,19].…”