Oxidative Changes in Ten Vegetable Oils Caused by the Deep-Frying Process of Potato

Abstract

Deep-fried foods are among the foods that are increasing in popularity both in the food industry and in domestic applications. While these foods stand out due to their sensory properties, oxidative alterations in frying oils cause concern. This study analysed the thermo-oxidative alterations that occur during deep frying with 10 commonly used culinary oils. Deep frying processes (180 ± 5°C) were carried out with a total of one liter of each type of oil and 100-g potatoes at every turn (sliced into 1 cm $\ast$ 1 cm $\ast$ 6 cm pieces). The process was carried out keeping the conditions constant for all oils and was repeated 10 times consecutively for all oils. The malondialdehyde and peroxide values of vegetable ghee (VG) were found to be 0.669 nmol/g and 21.0 mEqO2/kg, respectively, and were higher than those of other oils. Extra virgin olive oil (EVOO) (232.23) had the highest iodine value, while hazelnut oil (HO) (27.92) had the lowest value. While total polar compounds were within legal limits in all oils, they were higher (17%–23%) in EVOO, palm oil (PO), VG, and refined olive pomace oil than in other oils (17%–23%). As a result of this study, the thermo-oxidative changes in frying made with sunflower oil types are less than those of other oils, and the oxidative product/polar compound levels, which have adverse effects on health, are close to the legal limit in some oils (PO, VG, refined olive pomace, and corn oil).