| The blend oil was prepared by mixing soybean oil, palm oil, rapeseed oil and sunflower seed oil in a certain proportion,then adding complex natural antioxidants(vitamin E, tea polyphenols, rosemary) and TBHQ into it respectively. Then 32 h continuous frying bread stick test was carried out, and the polar component contents, acid values and peroxide values of the oil at different frying time were detected to analyze the effect of antioxidant on frying performance of blend oil. The results showed that after frying for 32 h, the polar component contents, acid values and peroxide values of three blend oils(without antioxidant, adding TBHQ, adding complex natural antioxidants )increased from 3.76%,0.2 mgKOH/g and 1.5 mmol/kg to 27.5%,28.30% and 30.72%,1.3,1.1 mgKOH/g and 1.1 mgKOH/g, 4.9,4.3 mmol/kg and 6.7 mmol/kg ,respectively,and the frying lives of three blend oils were 28,28,26 h with the frying life stipulated in GB 7102.1—2003 polar components content in frying oil less than 27% as evaluation index. The oil contents of bread stick fried by the three blend oils were 901%,13.21% and 10.01%,the contents of unsaturated fatty acid in the three blend oils during frying reduced by 4.6%,3.8% and 3.6%,while the contents of tran fatty acids increased by 126%,0% and 144%,and the loss rates of vitamin E in the three blend oils were 81.43%,80.61% and 86.65%. Based on the comprehensive analysis, it showed that antioxidants had no significant effect on the oxidative stability of blend oil during frying bread stick at high temperature.Compared with TBHQ, natural antioxidants had no obvious advantages in improving the frying stability of blend oil, but their effects were similar. And the significance of natural antioxidants in improving food safety was even more important and had promising prospects. |
