Inhibition of lipid oxidation in fried chips and cookies by Majorana syriaca

P>This study evaluates the antioxidant effectiveness of a natural extract obtained from Majorana syriaca in fried and baked foods. Majorana syriaca was extracted with ethyl acetate (yield 129 g kg-1, dry basis) and the extract was added to refined corn oil at a concentration of 500 ppm. The oil was used in deep frying of potato chips at 185 degrees C and in making baked cookies. Potato chips and cookies were further subjected to accelerated oxidation at 70 degrees C. The protection of the frying oil was moderate as indicated by the polar content and conjugated dienes (CD) measurements, however, a remarkable improvement of the oxidative stability of the fried chips was observed through the decrease of peroxide value (PV) and CD by 59-72% and 51-79%, respectively, compared to samples with no additive. Also, the PV and CD of cookies decreased by 79% and 72%, respectively.