In the present study, an attempt was made to investigate the effect of stearic acid on the autoxidation of the commercial rice bran oil.
Rice bran oil samples with stearic acid at 0.1, 0.3 and 0.5% level were kept at 45±0.3℃ for 40 days. The rate of autoxidation of each samples was estimated regulary on the basis of the changes of peroxide value, acid value, anisidine value and the fatty acid composition.
The results were as follows :
The peroxide, acid and anisidine values of the rice bran oil with the stearic acid at 0.1, 0.3 and 0.5% levels during the autoxidation increased as compared with that of the rice bran oil without the stearic acid. The induction period of the rice bran oil without the stearic acid, control was 19.8 days, while those of the bran oil with stearic acid at 0.1, 0.3 and 0.5% levels varied 19.0 days, 17.7 days and 14.2 days, respctively.
In conclusion, it seemed that stearic acid acted as weak prooxidant when added at 0.1, 0.3 and 0.5% levels to the commercial rice bran oil. The prooxidant activity of the stearic acid appeared to depend on the oxidative mechanism and their concentration.
|