Frying stability of canola oil supplemented with ultrasound‐assisted extraction of Teucrium polium

In this study, antioxidant activity and protective effects of Teucrium polium extract in stabilizing of canola oil during frying were tested and compared to synthetic antioxidant, BHA. Total phenolic, α‐tocopherol, flavonoid, and condensed tannin content of Teucrium polium extracted by ethanol ultrasound‐assisted were 60.90 mg/g, 103.66 μg/ml, 4.36 mg/g, and 3.77 mg/g, respectively. Moreover, IC(50) of the extract was 924.21 ppm. Canola oil samples containing 200, 600, and 1,000 ppm of the extract were heated at 180˚C for 30 hr and compared with BHA. Progress of oil oxidation was determined by measuring their peroxide value (PV), acid value (AV), iodine value (IV), carbonyl value (CV), color index (CI), conjugated diene value, and total polar compounds (TPC). The results showed that the extract was capable of retarding oil oxidation and deterioration significantly (p < .05) at all concentrations during frying. So, Teucrium polium extract can be used as natural antioxidant to retard oil oxidation.