Canola Oil Thermal Oxidation During Oven Test and Microwave Heating

Abstract

The oxidative stability of refined, bleached, and deodorized canola oil was evaluated under oven test (63 °C) and microwave heating conditions by absorptivity in the UV spectrum. Oil samples with BHA/BHT (1:1; 200 mg/kg) and citric acid were submitted to oven test for 6 days, and the linear coefficient of correlation between peroxide value and absorptivity at 232 nm was determined. Control samples showed a peroxide value of 58.50 mequiv/kg and absorptivity at 232 nm of 10.264 after 6 days of oven test. Absorptivities at 232 and 270 nm increased during 36 min of microwave heating (800 W, 2450 MHz), reaching 11.250 and 1.646, respectively. During initial stages of microwave heating (0-6 min), peroxide values differed significantly between control and the antioxidant-treated samples. After this period, peroxide value did not correlate with absorptivity at 232 nm; however, the presence of secondary products of oxidation was correlated with the decrease of peroxide value. © 2001 Academic Press.