Study Of Food Safety Based On Fluorescence Spectrum Detection

Food safety problem not only hurts people's life and health, but also affects people's attitude towards food consumption seriously, which will cause no belief in food safety among people and result in economical great losses.The job and mission of those skilled over detection field is : updating, completing and improving method of food safety detection; making progress in high preciseness, simplicity and good selective performance of method; using advanced detective technique to measure food sample qualitatively and quantitatively, and distinguishing them . The aim of the thesis is based on these. Rice wine is a kind of Chinese important wine, which is an important food among Chinese people. Acid orangeⅡis forbidden to used in food industry, but because its good coloration, illegal merchants put it in food production, mixing some substances for edible food additive. Tartrazine is a kind of man-made edible pigment, because of its toxicity to some extent, the maximum usage of it in food industry is 100ug/ml. Home and abroad, the fluorescence spectrum of these three have not been reported yet, and the study about the thesis fill in the blank.We use physical method to study of rice wine, acid orangeⅡ, tartrazine respectively, lay the foundation of detecting the three qualitatively and quantitatively using fluorescence spectrum in food safety area. The fluorescence spectra of 3 kinds of different storage age Shao Xing rice wine induced by suitable UV-light have been found in this paper through experiment, and the emitting mechanism of Shao Xing rice wine is discussed. The experiment of detection of acid orangeⅡbased on fluorescence spectra is reported, and fluorescence polarization spectrum, inside law of molecule are also discussed. In addition, detecting tartrazine solutions of different concentrations quantitatively, utilizing BP neural network to calculate the spectra of tartrazine solution, and prove the means can forecast spectrum information well.Through rice wine experiment, we have compared and analyzed their fluorescence spectrum comprehensively and in detail by using three-dimensional contour and two-dimensional fluorescent technique, and gotten their peak wavelengths are all in the vicinity of 500nm. 375nm UV-light is the best induced light for 3 storage age wine, and 370nm, 374nm are for 5 storage age wine and 8 storage age wine. The emitted fluorescence exist in 400nm to 680nm, which have wide peak. More over, the emitting mechanism of Shao Xing Chinese rice wine is discussed. We also have supposed the changing process of molecular structure of wine, and tried to explain the similarity and difference of fluorescence spectra of 3 kinds of wine. The reason of wide fluorescence peak is also analyzed.The experiment of detection of acid orangeⅡbased on fluorescence spectra is reported, and the fluorescence spectral characteristics, inside law of molecule are also discussed. The result shows that the emitted fluorescence exist in 310nm to 390nm when induced by ultraviolet radiation between 230nm to 290nm, and the peak wavelength is 350nm, and best induced light is 250nm.The intensity of fluorescence polarization spectrum decreases in a linear law, with polarization probing angle increasing, and the polarization degree is 0.783.The orientation characteristics of molecule is considered. More over, through analysis it is considered that the existence of structure of benzene and naphthalin in molecule is one reason of emitting fluorescence, and single-line excitated state of nitrogen-bond by induced light is another.The experiment of fluorescence spectra of tartrazine is reported: its fluorescence spectral is described with three-dimensional technology and the solutions of 8 kinds of different concentrations are also detected. The result shows that the emitted fluorescence exist in 450nm to 800nm when induced by light between 300nm to 335nm, the peak is at 565nm, and best induced light is 315nm. Within range of solution concentrations of 10ug/ml to 100ug/ml, the intensity of fluorescence spectra enhances with the concentration increasing. Because of BP neural network has the function of good nonlinear speculating ability, it is worthwhile to use it to forecast fluorescence spectra. The authors utilize the spectra of tartrazine solution of 100ug/ml to calculate, and prove the means can forecast spectrum information well, the normalized absolute error is less than 0.025.The research results could supply theoretical and experimental proof to study of fluorescence spectra of rice wine, acid orangeⅡ, tartrazine in area of food safety detection. Contribute to the development of detection of fluorescence spectra in experimental method. Combined with three-dimensional display, polarization technique and BP neural network, we use detection of fluorescence spectra to improve method of food safety detection.