The Adulteration Detertion Of Fried Waste Oil In Edile Oil

This topic used the common edible oil-corn oil and soybean oil as raw material topreparate the old fried oil,analyse the changes of oil quality in the process of frying, find thesensitive indicators in the frying process, and explore a accurate and fast fried method for thefried oil adulteration detection.①In the topic the variation of oil quality in frying process was explored systematically,and various indicators of frying oil was analyzed. Oil quality fission in the process of deepfrying performances both on the physical indicators, and through chemical index. The oilcolor and light transmittance are the sensitive physical indicators.The absorbance increasegradually as the extension of frying time. The carbonyl value of soybean oil frying15h was tothe highest value which is beyond the nation health standard. P-anisidine value is sensitive tohigh temperature, increases quickly at the beginning of frying, and was up to180.76mg/g.Mda is a substance that is harmful to the body, It reaches the maximum when the oil fried to18h.②By gas chromatography,in the soybeen oil the linolenic acid (c18:2)and oleic acid(c18:3) content significantly decreased, at the same time palmitic acid (c16:0) and oleic acid(c18:1) content increased. Grease of trans fatty acids content in the crude oil under1%.As thefrying time extended, the content of trans fatty acids increased gradually. When oil was fried9h appearing (t18:1).All trans fatty acids content increased order to against the trans linolenicacid (t18:3)> trans linoleic acid (t18:2)> trans elaidic acid (t18:1). Oil in the unsaturatedfatty acids can be converted into the corresponding trans fatty acids.③Frying temperature has a great influence vitamin E in oil. The tocopherol content ofcorn oil is88.91mg/kg, when frying24h decreased to4.16mg/kg. In soybean crude oil,vitamin E content is72.25mg/kg, when frying to24h to1.18mg/kg, basically do not containtocopherol in grease at this time,This implies the vitamin E are highly susceptible to damage.④Thin layer silica gel plate can be used to qualitatively detect the oil which will producesome molecular polarity is bigger than the normal vegetable oil composition in the fryingprocess. And as the frying time extend the polarity of the material increased gradually. Usingcolumn chromatography and thin layer chromatography determination of statutory polar substance content, the analysis shows that polarity substances contained in the crude oil isextremely low, generally below5%. As the extension of frying time, polar substance contentincreased gradually, the24h oil in frying, the polar components content has exceeded the27%target set by the state. Polarity composition can be used as an important index of oiladulteration.