Component Analysis Of Genetically Modified Soybean And Soybean Oil By NMR And Chromatography Techniques

Nuclear magnetic resonance(NMR)and chromatographic techniques combined with multivariate statistical analysis provide important ideas and strategies for variety identification and quality control of genetically modified foods.In this thesis,we successfully applied NMR and gas chromatographic techniques to analyze the composition of transgenic soybean oil and non-transgenic soybean oil.The major fatty acids including linoleic acid,oleic acid and linolenic acid in soybean oil and some quality parameters including iodine value,acid value,hydroxyl value and water content were quantitatively analyzed by NMR technique.Simultaneously,all types of fatty acids in soybean oil were quantified by gas chromatography(GC)The results indicate that only the content of C20:0 shows a significant difference between transgenic and non-transgenic soybean oil.The indifference of composition of transgenic soybean oil and non-transgenic soybean oil was further determined by performing multivariate statistical analysis based on the integral data of NMR and GC.Non-clustering in principal component analysis(PCA)and unsuccessfully orthogonal partial least squares discriminant analysis(OPLS-DA)discriminative model confirmed the significant indiscrimination in the composition between transgenic and non-transgenic soybean oil.In fact,the results from NMR and GC are mutually validated,which will become an effective and accurate method for assessing the composition of genetically modified(GM)soybean oil and controlling quality parameters.Based on the results of GM soybean oil and non-GM soybean oil,we have further conducted in-depth analysis on genetically modified soybeans.GM and non-GM soybeans show obviously different NMR spectral profile.Some important characteristic peaks were identified from the soybean spectrum,and in the spectral region of isoflavone which is beneficial to human,the contents of ginistin and genstein in the different samples fluctuate within a certain range,and the iso flavone content of non-GM soybeans is slightly higher than that of GM soybeans.The results were confirmed by multivariate statistical analysis including PC A and OPLS-DA,and the result shows the contents of unsaturated fatty acids,sucrose and other carbohydrates are significant higher in non-GM soybeans than in GM soybeans.Through gas chromatography,the proportions of fatty acids in the soybeans were quantified,and the content of C17:0,C22:0 and C20:1 acids was significant higher in the non-GM group than in the GM group,but the content of palmitic acid was significantly higher in the GM soybean than in the non-GM soybean.Although the mean values of oleic acid,linolenic acid and linoleic acid were different,there was no significant difference.