Research On Infrared Detection Of Aflatoxin In Vegetable Oil And Optical Characteristics Of Agarose Gel

An experimental research was aimed to study on the aflatoxin content and characteristic infrared spectra of homemade peanut oil after mildewed with Fourier transform infrared(FTIR) spectrometers and attenuated total reflection(ATR), in different temperature and relative humidity. The experimental results show that there are special absorption peaks of the samples containing aflatoxin in the vicinity of the 1710cm-1, which is preliminarily identified as the sample containing aflatoxin, and peanut storage period in the high temperature and humidity environment should not be more than 10 days.An identification analysis method for homemade vegetable oil and commercial edible vegetable oil was developed with the standard normal variate(SNV), principal component analysis(PCA) and Fisher discriminant analysis. Both of discrimination accuracy and cross validation accuracy reach 100%. At the same time, the identification of the oil doping in olive oil was studied by observing the position of the maximum absorption peak in the spectrum between 3009cm-1and 3005 cm-1of Fourier transform infrared spectrum. The peak of Unsaturated hydrocarbons(=CH)would change when the olive oil adulterated with soybean oil. So we could conduct qualitative analysis of adulterated olive oil by the shift of the peak position and intensity. And the quantitative analysis was conducted by the peak height, which could yield satisfactory result of linearity.Agarose gel and its composite hydrogel are ideal material for scaffolds with superior biological, mechanical and structural properties. In order to research the optical properties of agarose gel, which is applied to bio-printing, different concentration of agarose gel are prepared by mixing up agarose powder with distilled water in certain ratio after heating, dissolving and cooling. During the cooling progress, the refractive index of agarose solution at 55℃ and agarose gel is measured with Abbe refractometer. By comparing the refractive index of cell culture medium, the concentration of 0.00786 g/mL is proved to be the best concentration for agarose hydrogel as bio-printing substrate materials and biological scaffolds. Visible transmittance spectrum, near infrared transmittance spectrum and Attenuated total reflectance-Fourier transform infrared spectrum of agarose gel and cell culture medium were measured, which shows that there is no absorption peak in the spectrum of agarose gel at the wave band from 400 nm to 1100 nm, and the maximum absorption is only 0.1711Abs; In the range of infrared spectrum, agarose gel has the same absorption properties with cell culture medium, except for an unique absorption property at 2966cm-1 in the spectrum of cell culture medium. The experiments of the laser scattering characteristic of the surface of agarose gel show that the 440 nm laser has the strongest laser scattering intensity, while the 532 nm laser has the weakest one. Meanwhile, the smaller the concentration of agarose gel is, the stronger the scattering is.