TPCs of PO added or not with basil essential oil during repeated frying oils and fats is a well-accepted Determination of TPC in abused the method due to its accuracy and reproducibility. It provides oils most reliable measure of the extent of deterioration in frying and fats. The level of polar compounds is a good indicator of the quality of used frying oils and fats, giving information of the total amount of newly formed compounds having higher polarity than that of triacylglycerols (Abdulkarim and others 2007). TPO of PO without antioxidants and PO added with 200 ppm and 500 ppm of basil essential oil after 0, 1, 3, and 5 d of frying of French fries are shown in Table 2. The TPC percentages increased as frying usage increased. Initial (fresh olein) TPC percentage in the studied samples showed values between 3.56 and 4.06 with no significant difference (P 0.05). In some cases, TPC values in PO without antioxidant are comparable or lower (only after 3 d of frying to the calculated for PO with 200 ppm of basil essential oil. Some concentrations of natural antioxidants could promote this, as it was observed by Warner and Gehring (2009) when added citri acid to soybean oil for frying. However, at the end of the stud a significant difference (P 0.05) was detected. PO added with 500 ppm of basil essential oil reported the lowest TPC percentag along the frying process; the final TPC was 13.76%. This val similar to the reported for PO added with 200 ppm ofTBHQ (i after 4 d off frying, determined by 2011); thu basil essential oil was more efficient preventing polymerization than the synthetic TBHQ under the same conditions of study. At