The Study Of Dynamic Change And Safety Of Fish Oil Blended Oil During Deep Frying

The aim of this study was to investigate the dynamic change of fish oil blended oil (FO) during the frying process and evaluate the safety of the intake of frying fish oil blended oil in SD rats. This study consists of two rounds of frying potato chips with fish oil blended oil and common soybean blended oil (SO). The time of first frying round is1hr and the volume is10kg, with the temperature of180℃and frying a total of6kg potato chips. The second round lasts for6days,4hrs each day and the volume is15kg, with the temperature of180℃and frying a total of9kg potato chips. Take samples at4,8,12,16,20and24hrs, the color, viscosity, acid value (AV), peroxide value (PV), thiobarbituric acid value (TBA), carbonyl value (COV), total polar compounds (TPC) and polymers were analysed. One hundred and twenty8wks old SD rats,60males (223.8±12.8g) and60females (301.0±15.6g) were randomized into6groups (n=20,10males,10females), they were a fed diet contain fresh oil (SO and FO), frying for1hr oil (SOI and FO1), frying for24hrs oil (SO2and FO2), respectively. The rats were killed by decapitation at the end of8wks and16wks, respectively. Serum biochemistry parameters, lipoprotein lipids and fatty acid compositions were analyzed.The result indicates that the acid value in FO was significantly lower than that in SO during0-16hrs (p<0.05). The peroxide value was always higher in FO than that in SO (p<0.05). After8hrs, the polar compound and polymers in FO was significantly lower than that in SO (p<0.05). The specific fatty acid EPA+DHA (20:5n-3+22:6n-3) were significantly decreased with the frying time.There was no significant difference in food intake between different groups. The body weight of rats in SO2group was significantly lower than the rats in SO group (p<0.05). However, the difference was disappeared after8weeks. Female rats were more sensitive to the intake of frying oil and influenced the basophil, erythrocyte and hemoglobin. However, these parameters may effect by menstrual cycle. The intake of1hr frying FO has adverse effect on liver and kidney function in SD rats. The TPC of both frying oil after24hrs is22%above, which were all in poor quality state, the intake of different kinds of frying oils has no significant difference. Long term (16wks) intake of fish oil blended oil has positive effect on regulating blood glucose.Above all, under the condition of the present study, fish oil blended oil could be used for cooking. However, we suggest it could not to be repeated frying for long term.