Research On The Contents Of Deoxynivalenol In Maize Germ And Its Products

Corn oil which is rich in unsaturated fatty acids,vitamin E,phytosterol and other nutrients,has become one of the important edible oil in China.Corn is susceptible to mycotoxins,such as deoxynivalenol(DON).Corn germs are rich in oil and nutritious,which are easy to mildew in the conditions of high temperature and high humidity,thus were infected with deoxvnivalenol.As product of corn germ,corn meal and corn oil are also at the risk of being contaminated with DON.Vomit toxin has role of "carcinogenic,teratogenic,mutagenic" and human and animal intake food which are contaminated by DON will get acute or chronic poisoning,causing great harm to the health.GB 2761-2017 in the provisions of mycotoxins in food limited in cereals and cereal products that DON limit is 1000 ?g/kg and does not require the limit of DON in corn germ(intend to make oil)and corn oil.In view of China's food safety,DON in corn germ and corn oil has been paid much attention to.This research is focuse on maize germ and its products – corn germ cake and meal as well as crude oil;make sure that multifunctional purification column and HPLC method is fit to the determination the concentration of DON in corn oil;research DON content levels of maize corn germ,crude oil and refined oil in different regions;DON contents in corn germ?corn germ cake and meal?coil oil by different oil producing process;DON contents in corn germ?corn germ cake and meal?coil oils under different corn germ storage conditions;the optimum technological for removal DON in corn oils.(1)A method was established for the determination of deoxynivalenol in corn oil by high performance liquid chromatography(HPLC).Sample extracted by ultrasonic of acetonitrile-water(volume ratio 80:20),and purificated by multifunctional purification column.The mobile phase was acetonitrile-water(volume ratio 16:84).The result showed that linear range of DON content was 0.01 ~ 5 ?g/m L with correlation coefficient of 0.99997,Y=63626.6x+390.1.The mean recoveries of the spiked at three levels range from 88% to 105%,and the relative standard deviation range from 1.8%~5.3%.(2)Maize germs samples(collected from Jiangsu,Anhui,Hebei,Henan and Shangdong)and corn crude oils samples(collected from Sichuang,Jilin,Guangzhou,Heilongjiang,Shangdong and Hebei)from corn deep processing plants and refined corn oils from supermarkets in China were analyzed for DON by HPLC combined with ultraviolet detection.The DON positive ratios in Jiangsu(n=10),Hebei(n=18),Anhui(n=10),Henan(n=15)and Shangdong(n=16)were 100%?100%?86.6% and 93.7%,respectively,while the average concentration of DON were 678.4?616.6?425.9?322.5 and 199.3 ?g/kg,respectively.The DON contents of samples were different in the same areas.The positive ratios in crude oils(n=30)and refined oils(n=40)were 23.3% and 12.5%,while,the average were 40.7 ?g/kg and 14.5?g/kg.The low DON contents in corn oils means low risk to health.(3)In this study,crude oils were extracted from five kinds of maize germs with different DON contents which collected from different firms by solven extraction and hydraulic pressing methods.Though these ways,crude oils,meals and cakes were obtained.The concentrations of DON in those samples were determined by HPLC and the DON content in different samples were detected.The results showed the average concentration of DON in maize germs,solvent extracted maize oil and pressing corn oil were 617.44?101.82 and 48.4 ?g/kg,respectively,while the average contents in the corresponding meals and cakes were 524.92 ?g/kg and 601.36 ?g/kg.For the same raw material of corn germ,the extracted crude oil DON contents were higher than pressed crude oils and extracted corn germ meal DON contents were lower than pressed corn germ cake.DON content in crude oils was significantly lower than that of corn germ,there is no significant difference between meal and cake(P >0.05).In this experiment,the DON contens in all samples were lower than the national standard(1000 g/kg).(4)The corn germ with different moisture content(5%?9%?12%?18%)were stored for 30 d at 25 ?,with relative humidity of 45%(the moisture content were 9%)were stored at 25 ? with different relative humidity(75%?85%?95%)for 30 d.During the storage,the moisture content?crude fat content and DON content of the germ?meal and oil were detected.In order to analyze the effects of storage on DON content and quality of the corn germ?meal and oil.The result showed that,crude fat contents had no obvious changed and was light mildew with 5% and 9% initial moisture,while crude fat contents decreased 1.21% and 2.74%,respectively.Heavy mildew with 12% and 18% initial moisture.The DON contents in different moisture content of maize germs and meals ranging from 160.9~489.5 ?g/kg and 240.2~329.5 ?g/kg,respectively.The quality of corn germ had no obvious change under the condition of 75% relative humidity,while the qualities of corn germs turned bad under the condition of 85% and 95% relative humidity with the crude fat contents decreased 1.93% and 3.87%,respectively.The DON contents in different relative humidity of maize germs and meals ranging from 153.5~484.7 ?g/kg and 270.6~439.6 ?g/kg,respectively.All corn oils obtained from different storage conditions were not detected DON.The concentrations of DON in all the tested samples were lower than the limit amount of GB 1000 ?g/kg.(5)In this study,the DON removal effects from maize oil of different refining process were studied by investigating the DON removal rate mainly.The results showed that high and low DON content concentration(1745.43 ?g/kg,456.73 ?g/kg)in corn oil after degumming,deacidification,bleaching and deodorization could achieve a lower DON levels.For DON in the process of refining removal effect is good for degumming and deacidification.Under the condition of high concentration of DON content hydration degumming of acid and alkali refining removal rate could reached 88.94% and 90.07%,respectively,after removal of DON content was 193.06 ?g/kg and 173.29 ?g/kg.Under the condition of low concentration DON content degumming and deacidification,removal rate could reached 59.54% and 58.23%,respectively,and the DON contents were 184.79 ?g/kg and 190.79 ?g/kg.The results provide reference and technical support for the optimization of corn oil refining process conditions and technical improvement.