Thermal oxidation of rice bran oil during oven test and microwave heating

Abstract

The purpose of the present study was to evaluate the oxidative stability of physically refined rice bran oil (RBO) under oven heating at 63°C and microwave heating conditions by absorptivity. Oil samples with tertiarybutylhydroquinone (TBHQ) (100 ppm and 200 ppm), citric acid (CA), butylhydroxyanisole/butylhydroxytoluene (BHA/ BHT) and in other combination, BHA/BHT+CA were submitted to oven test for 6 days, and the linear coefficient of correlation between peroxide value and absorptivity at 232 nm was determined. The gradual increase in peroxide value and absorptivity at 232 nm was observed in all the RBO samples, control and antioxidant added. RBO samples added with tertiary-butylhydroquinone (TBHQ) had shown the least peroxide value and absorptivity as 6.10 and 5.8 respectively, when added at a concentration of 200 ppm whereas; the control RBO samples had shown the maximum values. The peroxide values obtained from the correlations during the oven test were found closely correlated with the peroxide values obtained during the microwave oven heating experimentally. The effect of microwave heating on the oryzanol content and p-anisidine value was also observed and the correlation to the oven test was established. The oryzanol content and p-anisidine values obtained after oven heating when correlated to the microwave heating data showed the oryzanol content 13,371, 13,267 and 13,188 ppm after 1 day, 4 days and 5 days respectively which were closely correlated with the experimental value.

Retention of Carotenes and Vitamin E, and Physico-chemical Changes Occurring upon Heating Red Palm Olein Using Deep-fat Fryer, Microwave Oven and Conventional Oven

“…Hence in the current study, no major hydrolytic degradation was observed with regards to FFA content in both test fats studied. Similar to current study, heating oil itself at 180 did not cause major triacylglycerol hydrolysis 14,22,23,27,33,34 . However, in the presence of food matrix, the acidity values rapidly increased probably due to lipases reaction 6, 35 40 .…”

Molecular Distillation-Induced Deacidification of Soybean Oil Isolated by Enzyme-Assisted Aqueous Extraction: Effect of Distillation Parameters

“…These species are very unstable and are readily transformed to secondary oxidation products at high temperature, which increases decomposition efficiency. Therefore, PV can be viewed as an indicator of oil oxidative stability [28]. Figure 2 shows the effects of distillation parameters on the peroxide and p-anisidine values of soybean oil.…”

Effect of storage conditions on physico-chemical properties and fatty acid ratio, C18:2/C16:1 of blended fat

“…The changes in PV may be due to the amount of oxygen that must be absorbed or peroxides that must be formed to produce noticeable oxidative rancidity in blended fat which varies with their composition (Mishra et al, 2010). PV of control sample was initially 6.57 for 3:2 blended fat ( Table 1).…”