Alternative Methods of Frying and Antioxidant Stability in Soybean Oil

A study on shallow and parfrying in soybean oil as alternatives to deep frying and evaluation of stability of a formulated antioxidant administered to the oil was conducted. Potato wedges were deep, shallow and parfried in soybean oil for optimized time and temperature. A citric acid based antioxidant using BHT was formulated and administered to the oils before frying. The performance of antioxidant was assessed by studying its physicochemical properties and DPPH radical scavenging activity with repeated frying. In the oils administered with the formulated antioxidant, highest and least values obtained were: FFA (% oleic acid) of 4.90% in deep frying and 4.55% in parfrying, peroxide values (mEq/Kg) of 6.50 in deep frying and 5.39 in parfrying, para-anisidine value of 6.92 in deep frying and 5.91 in parfrying, TOTOX values of 19.93 in deep frying and 16.70 in parfrying, iodine values (g I2/100 g oil) of 98.56 in deep frying and 102.63 in parfrying, conjugated dienes of 4.88% in deep frying and 4.32% in parfrying and conjugated trienes of 5.7% in deep frying and 5.15% in parfrying. The physicochemical tests revealed least oxidation in oils administered with the formulated antioxidant in parfrying and the most in deep frying, indicating parfrying to be the most suitable frying mode. The DPPH radical scavenging activity of the parfried oil showed 31.52% decrease after the fourth fry. From statistical analyses (p<0.05), it was concluded that the formulated antioxidant significantly limited oxidation in the oils with respect to the control until the third fry (8 days).