Antioxidant effect of rosemary and ferulago extracts and synthetic TBHQ on oil oxidation during deep-frying

The application of synthetic antioxidants is restricted because of their potentially toxic and carcinogenic decomposition products. Studies on natural antioxidant alternatives to synthetic antioxidants are of immediate importance. The present study compared the antioxidant effects of two natural antioxidants: rosemary extract (RE) and ferulago extract (FE) to synthetic TBHQ antioxidant on oil oxidation during deep frying. A mixture (1:1; w/w) of sunflower and palm olein oil was used in this study. Antioxidant treatments added to the frying oil were 500 ppm RE، 1000 ppm FE، or 100 ppm TBHQ. The antioxidant activity of the treatments was examined using the DPPH radical-scavenging assay. Oil degradation and oxidation during deep frying were monitored by measuring the total polar compounds (TPC)، peroxide and anisidine values. The DPPH radical-scavenging assay showed that RE had higher antioxidant activity than FE. Of the 3 antioxidants، RE exhibited significantly better antioxidant activity as determined by the peroxide and TPC measurements (p < 0. 05). The anisidine value for TBHQ treatment was the lowest. In recognition of the negative effects of synthetic antioxidants، the results of the present research suggest that rosemary extract can be recommended as a substitute for TBHQ. The properties of ferulago extract require more investigations.