MATHEMATICAL MODELING AND STABILITY OF SUNFLOWER OIL UNDER DIFFERENT STORAGE CONDITIONS

Sunflower has seeds with notable physicochemical and nutritional characteristics. The oxidative stability of sunflower oil depends on physical factors and the action of chemical mechanisms during storage. To define this stability, there are well-documented methods, however the use of mathematical modeling to simulate quality parameters is useful when it is not possible to perform measurements in the laboratory or to carry out projections and better understand the behavior of the product. Therefore, this work aims to evaluate the sunflower oil stability during storage under different conditions and to propose mathematical models capable of simulating the assessed quality parameters. The analysis involved the determination of free fatty acid content and peroxide index of samples exposed to five distinct home-simulated conditions for 6 weeks. Thus, the impact of storage temperature and exposure to light and oxygen was evaluated. The data were analyzed using statistical tests and the partial least squares method was used for modelling. The results indicated that the oil did not present levels of free fatty acids above those allowed by legislation (< 0.3%) for all storage conditions studied. However, the levels of peroxide index were high (58.95 ± 0.72 mEq.Kg-1) in the sample with the incidence of light and oxygen at room temperature in six weeks of storage, evidencing a process of deterioration. The proposed model to evaluate the peroxide index was considered adequate. Among the storage conditions studied, the most impactful factor for oxidative stability was the presence of oxygen and the best condition was the use of refrigerated temperature in the absence of light and oxygen. Therefore, keeping the packaging closed, protected from light and in a cool place directly influences the quality of the oil, as it delays the occurrence of oxidation reactions and the consequent deterioration of the product.