Table 1 shows the CDV for the studied POs, which increased with the time of use and were lower when basil essential oil was added. CDV at the end of the study (5 d, around 20 h of fry- ing) was between 13.8 and 17.7 mmol/L, lower than the reported by Saguy and others (1996) for cotton oil after 22.3 h of fry- ing (4.50 mmol/L) and those by Farhoosh and Tavassoli Kafrani (2011) for sunflower oil without antioxidants after 20 h of frying (45.5 mmol/L). Thus, the oxidation level for PO added with basil essential oil can be considered as low, with a positive effect of this essential oil able 2 shows the p-anisidine values (p-AV) of PO without antioxidants and PO with 200 and 500 ppm of basil essential oil before and after 1, 3, and 5 d of frying of French fries. Initially, the p-AV of the 3 fresh samples was low and a significant difference (P 0.05) was detected among them. However, a sudden increase in the 3 samples was detected after the 1st day of frying and continued to increase until the 5th day. At the end of the process, both samples added with basil essential oil showed similar p-AV with no significant difference between them (P> 0.05). On the other hand, PO without antioxidant showed the highest p-AV at the end of the process and it was significantly different (P< 0.05) in comparison with the other 2 samples added with basil essential oil. Similar results were reported by Lee and others (2002) when testing different concentrations of spinach powder as a natural antioxidant in soybean oil, the p-anisidine reported values ranged between 80 and 120.