Integrated Analytical Assessment of Edible and Essential Oils: Thermal, Oxidative, Chromatographic and Spectroscopic Characterization

This study investigates the physicochemical, thermal, oxidative, and spectroscopic properties of vegetable and essential oils using an integrated multianalytical approach. Commercial samples of avocado oil, grape seed oil (samples A and B), sucupira oil (samples A and B), eucalyptus essential oil (samples A and B), and sweet orange essential oil (samples A and B) were evaluated by differential scanning calorimetry (DSC), gas chromatography (GC-FID), Rancimat oxidative stability analysis, UV–Vis absorption spectroscopy, and excitation–emission fluorescence spectroscopy. Samples A and B represent different commercial samples of the same oil type obtained from different commercial products. DSC analyses revealed distinct thermal transition profiles associated with lipid composition and molecular organization. Avocado oil exhibited the most complex crystallization behavior and the highest transition enthalpy, indicating greater thermal organization. Chromatographic analysis demonstrated predominance of monounsaturated fatty acids in avocado oil, especially oleic acid, whereas grape seed and sucupira oils showed elevated concentrations of polyunsaturated fatty acids, mainly linoleic acid. Oxidative stability analysis showed significant differences among the samples, with avocado oil presenting the highest induction period (12.38 h), while eucalyptus, orange, and sucupira oils exhibited very low oxidative stability. UV–Vis and fluorescence analyses demonstrated distinct spectral profiles related to pigment composition, antioxidant compounds, and oxidation state. Overall, the results confirmed strong agreement among thermal, chromatographic, oxidative, and spectroscopic analyses, demonstrating the applicability of integrated analytical approaches for comprehensive characterization of vegetable and essential oils.