Impact of Frying Process on Physicochemical Indices of ‎Edible Vegetable Oils in Libya with Varying Omega Fatty ‎Acid Content

Abstract

The high temperatures employed during the frying process, in the presence of oxygen and water, induce ‎significant chemical transformations in oils, including oxidation, polymerization, cyclization, and ‎hydrolysis. It has been observed that the frying temperature, type of frying oil, presence of antioxidants, ‎and the type of fryer used can impact the extent of hydrolysis, oxidation, and polymerization of the oil. ‎Hence, the objective of this research was to investigate the effects of the frying process on various ‎physicochemical indices of edible vegetable oils with differing omega fatty acid contents. In this study, we ‎focused on assessing key physicochemical characteristics that can serve as quality control parameters for ‎commonly available edible vegetable oils in Libyan markets, namely virgin olive oil, corn oil, sunflower oil, ‎and flaxseed oil. These oils were individually subjected to frying at 180°C for 10 minutes, repeated for ‎three consecutive cycles. The fresh oil, as well as the oils after the first, second, and third frying cycles, ‎were analyzed. The findings indicated that all the examined parameters (free fatty acid percentage, ‎peroxide value, ρ-anisidine value, totox value, and thiobarbituric acid reactive substances) exhibited an ‎increase with prolonged heating time. Among the oils tested, flaxseed oil demonstrated the highest values ‎for the analyzed parameters, followed by sunflower oil, then corn oil, and finally olive oil after three ‎successive frying cycles.