Oxidation of fatty acids in oils subjected to mild temperature stress: The case of grapeseed oil

Vegetable oils are among the most widely used ingredients and foods globally, with production ranging from artisanal to highly automated systems, making them a widespread commodity. Continuous evaluation of oxidative parameters is crucial to improving their sensory, qualitative, and environmental aspects. Grapeseed oil, due to its characteristics and supply chain, is a suitable matrix for oxidation studies with a relatively abundant dataset. This study investigates the physicochemical properties and oxidative stability of edible oils, specifically grapeseed oil, under mild temperature stresses. Various quality and oxidation indexes were assessed, including peroxide value, p-anisidine value, fatty acid composition, oxidized fatty acids content, volatile compounds, and general oxidative resistance. Analytical and instrumental methods, such as gas chromatography and OXITEST®, were employed. Results show that in an unsaturated matrix like grapeseed oil, oxidative degradation under mild temperatures follows complex kinetics that cannot be fully described by a single index. This is due to varying reactivity among fatty acids and simultaneous formation and inactivity of markers like peroxides and p-anisidine, respectively. The analysis of oxidized fatty acids proved to be a valuable tool for evaluating minimally stressed matrices and represents an additional parameter to enhance qualitative analysis of vegetable oil products.