DETERMINATION OF THE SHELF LIFE OF SUNFLOWER OIL USING THE OXITEST INSTRUMENT

Sunflower oil is a strategically important product for Ukraine. One of the main issues affecting its quality during transportation and storage remains peroxide oxidation. Establishing minimum shelf life periods is a key step in ensuring the stable quality and safety of sunflower oil at all stages of the production and logistics chain. The article examines modern approaches to assessing the oxidative stability of oils, in particular the instrumental method of accelerated oxidation of samples using the Oxitest device. It is shown that traditional chemical methods, such as determining peroxide and anisidine values, are labor-intensive and require reagents, which limits their suitability for rapid quality control. To optimize the quality control procedure during storage, the effectiveness of a kinetic approach based on the Arrhenius and Eyring equations was investigated. For unrefined sunflower oil, induction periods determined using the OXISoft™ software were used to describe the kinetics, as well as rate constants of the oxidation reaction at temperatures of 363, 373, and 383 K. Based on the temperature dependence of ln k versus 1/T, the activation energy (84.99 kJ/mol) and pre-exponential factor were calculated. The dependence of ln (k/T) on 1/T was used to determine thermodynamic parameters: enthalpy (81.85 kJ/mol), entropy (–41.28 J/(K·mol)), and Gibbs free energy, whose values increased with temperature, confirming the non-spontaneous nature of the reaction. It was shown that increasing temperature from 288 to 298 K is accompanied by an increase in the oxidation rate and a reduction in the shelf life of the oil samples, calculated based on the dependence of log IP on T. The obtained results confirm the feasibility of using the Oxitest device combined with kinetic analysis for rapid, reagent-free, and environmentally safe assessment of oil oxidative stability, which is promising for modeling the minimum shelf life of oil products.