Research On The Application Of NIR In Food Inspection And Conducting Oil Test

Near infrared spectroscopy (NIR) analysis technique owns the characters of quickly, easily sample treatment and non-destructive, which can be applied for simultaneous quality evaluation and quantitative analysis. This technique has been paid more and more attention recently and been widely used in the fields of petrochemicals, organic synthesis and analysis, environmental analysis, food and clinical analysis, etc.. In this thesis, three detected models had been established and been applied in food safety detection and conducting oil test. The thesis includes four chapters.In the first chapter, the conception and characteristics of the near-infrared spectroscopy technique and the procedure about the application of NIR and the modes of data processing were described. In addition, the application of NIR in the fields of food analysis and industrial oil testing were introduced also. At last, the purpose and contents of this research had been pointed out.In the second chapter, the NIR technique was applied to identify and quantitative analysis three bacteria in milk, i.e Zanretsuken e. coli, Lactobacilli, and Staphylococcus aureus. The principal component analysis (PCA) method was used to identify whether the milk samples contained bacteria and the species. And the partial least square (PLS) was applied to establish the quantitative analysis model for each bacterium. And then these models were successfully used to determine the bacterial amount for these three species of bacteria in solution in the range of 2-8 log CFU/mL. Researches showed that the root mean square error of calibration(RMSEC) are 0.30,0.74,0.57 respectively, and the root mean square error of prediction (RMSEP) are 0.37,1.08,0.77 respectively. We also simultaneously detected the amount of each type of bacteria in milk which contained Enterobacter sakazakli and Staphylococcus aureus, the RMSEC are 0.58 and 0.63, the RMSEP are 1.52 and 1.57, respectively. The established method can be applied in the rapid milk examination.In chapter three, an analyzing method which can be applied to identify the genetically modified soybean and non-genetically modified soybean had been developed based on the near-infrared diffuse reflection spectroscopy and PCA analysis, the accuracy was 95%. PLS was applied to establish the quantitative analysis model for the proportional of the genetically modified soybean in the non-genetically modified soybean. Results showed that the average relative error was-0.460, the RMSEC and RMSEP are 1.516 and 1.337 respectively. This study provides a simple, rapid and accurate method to detect the Genetically Modified Food.In chapter four, Near-infrared spectroscopy had been applied to distinguish mineral and synthetic conducting oil. And a model which can recognize the brand of the oil from the same type of conducting oil had been developed. The average accuracy rate of prediction can reach 95%. Studies have shown that near infrared spectroscopy can be applied to recognize the conducting oils with different performance.