| The accelerated oxidation test of fragrant and refined sunflower seed oils, as well as sunflower seed oils added with tertiary butyl hydroquinone (TBHQ) were carried out by Schaal oven method. By investigating the peroxide value, acid value, contents of vitamin E, sterol and volatile flavor components of the four samples during the accelerated oxidation, the differences in oxidative stability, predicted shelf life, nutrient and volatile flavor component contents, and the effect of TBHQ on oxidative stability and other comprehensive qualities of fragrant and refined sunflower seed oils were analyzed. The results showed that the predicted shelf lives of the fragrant and refined sunflower seed oils before and after adding TBHQ were 64, 272, 48 d and 96 d respectively with the peroxide value reaching the corresponding national standard limit for sunflower seed oil as the evaluation indicator.After accelerated oxidation for 21 d, the loss rates of vitamin E of the four sunflower seeds oils mentioned above were 50.63%, 23.72%, 32.51% and 17.82%, respectively, and the loss rates of sterol were 20.73%, 13.22%, 15.43% and 8.30%, respectively.The initial fragrant and refined sunflower seed oils contained 9 classes (98 kinds) and 9 classes (91 kinds ) of volatile flavor components, and the total amounts were 10.31, 0.74 mg/kg, respectively, the highest contents in fragrant sunflower seed oil was olefin compounds(accounting for 46.94%), followed by heterocyclic compounds (accounting for 31.23%), pyrazines compounds were the main components of heterocyclic compounds (accounting for 75.16%); the highest content in refined sunflower seed oil was alkanes compounds (accounting for 37.84%), followed by olefines compounds (accounting for 35.14%), and no heterocyclic compounds were detected. After 21 d of accelerated oxidation test, there were only 45 volatile flavor components in the blank fragrant sunflower seed oil, and the contents of aldehydes and ketones increased significantly, while the heterocyclic compounds were almost totally lost; the contents of aldehydes and ketones in blank refined sunflower seed oil increased significantly (accounting for 65.20% and 20.74%, respectively).The addition of TBHQ might contribute to the maintenance of the quality and freshness of sunflower seed oil, but its decomposition product tert-butyl-p-benzoquinone greatly increased the content of quinones in sunflower seed oil, which adversely affected the inherent flavor and quality of sunflower seed oil. |
