Effects of deep-fat frying process on the oil quality during French fries preparation.

The performance of the sunflower oil in deep-fat frying was assessed by evaluating the efficacy of linoleic acid level and composition of tocopherol isomeric on its frying stability. The oil was used as a frying media to fry potato strips for 6 h daily for 7 days. Standard procedures for the measurement of used frying oil degradation such as fatty acid composition, acid value, anisidine value, conjugated diene value, total polar compounds and tocopherol concentration were used. At analogous composition of tocopherol isomers, the high oleic sunflower oil with smaller value of linoleic acid content indicated higher frying stability than the oil with higher linoleic acid level. This, indicating that the high oleic sunflower oil frying efficiency was depended mainly with the oil linoleic acid content and the composition of tocopherol isomers showed no significant effect. Also, the α-tocopherol degradation was lower compared to the corresponding degradation of γ-tocopherol.