The Studies On Floc Sediment Formation And Removal Method In Sesame Oil

Sesame oil is a traditional flavor oil which is very popular with pepole like inchina. Sesame oil is rich nutritional value which the content of oleic acid and linoleicacid is so high. In recent years the consumption of sesame oil isrising year by year inour country, but with prolong storage time or under the condition of low temperaturesesame oil will often appear turbidity and floc sediment. In this paper sesame seeds(peeling sesame seeds, sesame seeds without peeling) are used as raw material toproduct sesame oil in several common production process, and then compare thesituation of sediment between them. One of the oil is used as the main object to studythe formation conditions of sediment in sesame oil, and use infrared spectroscopy,thin layer chromatography and mass spectrometry to test the composition of sedimentin sesame oil, and analyse the main component of sediment and then select theappropriate method to remove and observe the results.Compare the sesame oil of several production process, having found that thesediment in sesame oil which is used not peeling sesame seeds to produce is morethan which is used peeling sesame seeds. This indicates that the generation ofsediment in sesame oil and sesame skin has certain connection. Effect conditions ofsediment in sesame oil are mainly moisture, temperature and time. Under theconditions of moisture content of0.2%, a temperature of5℃and storaging9days,the sediment in sesame oil is maximum.Analysis of the physical and chemicalindicators of sediment in sesame oil hasfound that the residual oil is higher（82.07%）, and the rest is main wax ester(9.68%),protein(5.7%), phospholipids (0.874%) as well as small amounts of carbohydrate.Comparing the composition of sediment waxy and hexane precipitates of sesame skin,the result of IR and TLC showed that the composition between them were relativelysimilar. After mass spectrum detection, the main composition of sediment waxy insesame oil are alkanesC12-(15.82%), C14-(13.34%), olefinC18，C19，C20accounted for10.55%; palmitate and stearic acid ester are9.35%; palmitic acidaccounted for8.02%, the content of2,2’-methylene-bis-(4-methyl-6-t-butylphenol) is higher of30.66%.The main compositions of hexanprecipitates of sesame skin lipid are relatively similar,and mainly are palmitic acid and its methyl ester, hydrocarbons and phenolics.Thisfurther determines the formation of sediment in sesame oil and sesame skin havingcertain relations,it mainly is caused by wax substances.By using surfactants and cooling isolation to dewaxing of sesame oil, results showthat the method of surfactant is better thancooling isolation, the optimum conditionsare: surfactant addition amount of0.3%, mixing temperature of50℃and mixingtime of80min. Comparative validation experiments show that at low temperaturestorage conditions, dewaxing sesame oil did not appear floc sediment within30days,while not dewaxing hot-pressed sesame oil appear floc sediment. At the same time,although not dewaxing cold-pressed sesame oil did not appear sediment, but notdewaxing cold-pressed sesame oil were more cloudy than dewaxing cold-pressedsesame oil. Therefore, under low temperature conditions sesame oil dewaxing caneffectively prevent the formation of sedimentin sesame oil in a certain period of time.