Effect of the number of frying cycles on the composition, concentrations and risk of polycyclic aromatic hydrocarbons (PAHs) in vegetable oils and fried fish

Abstract

The use of the same batch of oil for deep-frying on several occasions is a common practice. This study sought to determine the effects of repeated frying cycles on the composition, concentrations and risk of polycyclic aromatic hydrocarbons (PAHs) in six types of vegetable oils and the samples of fish fried therein. The PAH concentrations in the oils were measured before use and after each of three successive cycles of frying. Fish was fried at each time of use of the oils and, also, monitored for their PAH content. The PAH content in all samples was determined by gas chromatography-mass spectrometry (GC–MS). The concentrations of Ʃ22 PAHs in the unused oils ranged from 43.3–2107 μg kg−1, while those in the used oil ranged from 40.8–4090 μg kg−1. There were significant changes (p < 0.05) in the concentrations and composition of PAHs with respect to vegetable oil types and number of frying cycles. The cancer risk values for the vegetable oils (10−4 to 10−5) after three frying cycles exceeded the acceptable risk value of 10-6 indicating a probable lifetime carcinogenic risk. However, adverse non-carcinogenic risks through consumption of these oils and fried fish were low.