Formation And Analysis Of Carbonyl Compounds In High-temperature Processing Of Edible Oil

The hydroperoxides from the formation of unsaturated fatty acid breaking during the heat process of edible oil,further decomposition of the resulting carbonyl compounds may produce odor,may also be harm to the human body.Because these small molecules of aldehydes and ketones contain active carbonyl,most likely with the food system in the amino or other components of the reaction,involved in the process of Maillard reaction,affecting the formation of hazards of harmful substances in food processing.Carbonyl compounds are important components of volatile substances in food,and are also important associated products for processing in oil heat-processing.It is a great of theoretical and practical value to study the formation of carbonyl compounds during the thermal processing of oil-heating,and also a great value for the complex mechanism of harmful substances in food processing.The main contents of this paper are as follows:(1)A high performance liquid chromatography method for the determination of carbonyl compounds was established and verified.The results showed that the method has good precision and stability.The carbonyl compound standard solution was repeated six times,and the peak area of the RSD value between 0.358%-1.748%.The stability of the derivatization of the sample within 12 h,the peak area RSD value between 0.149% and 1.94%,and the recoveries of the DNPH derivative of the fifteen carbonyl compounds in the sample were 82.896%-126.096%,indicating that the method can be used in experimental research.(2)Comparing the fatty acid composition of soybean oil,peanut oil,rapeseed oil and sunflower oil,the palmitic acid content of soybean oil and peanut oil is higher,the linolenic acid content of soybean oil and rapeseed oil is higher,and the soybean oil contains 51.85% Oleic acid,24.94% linolenic acid,peanut oil containing 32.17% linoleic acid,46.79% oleic acid,rapeseed oil containing 19.30% linoleic acid,62.88% oleic acid,sunflower oil containing 60.35% Linoleic acid,27.05% oleic acid.As the heating time increases,and the frying temperature increases,the content of unsaturated fatty acids decreases,and as the temperature increases,the rate of reduction is faster.(3)The formation of carbonyl compounds for soybean oil,peanut oil,rapeseed oil and sunflower oil were continuously heated at 150 °C,170 °C and 190 °C for 10 hours.During the heating process at 150 ? and 170 ?,the formation rate of carbonyl compounds is faster,and the content of carbonyl compounds such as nonanal,nonenal and hexanal are obvious.At 190?,with the heating time,the content of each time point is reduced,carbonyl compounds as volatile oxidation products and heat reaction intermediates,consumption intensified.From the carbonyl compounds and fatty acid changes of various oils and fats,the content of nonanal and nonenal is related to the change of oleic acid,and the content of hexanal and heptaldehyde may be related to the change of linoleic acid.(4)Using the rice cake and octopus as the representative of high starch and high protein food system,the rice cake and octopus were frying at the 170? with the soybean oil.The content of unexplored carbonyl compounds increased with the oil samples of non-fried food under conditions of 170°C.The content of acetaldehyde,acetone,hexenal,heptaldehyde and nonenal was always lower than that at each point Fried oil samples.Propionaldehyde,hexanal and nonanal are higher than those of non-fried oil at the beginning of heating,and the content of valeraldehyde is significantly higher than that of non-fried oil at each time point.