Application Study Of Near-infrared Two-dimensional Correlation Technology In Quality Analysis Of Edible Vegetable Oil

This study employing seven kinds of vegetable oils, olive oil, sunflower seed oil, colleseed oil, soybean oil, pomace oilve oil, peanut oil, maize oil) was tested with Antaris II FT-NIR(fourier transform near- infrared) Analyzer which wavelength resolution was set at 8 cm-1 and the spectral scanning range was selected from 4 000 cm-1 to 10 000 cm-1. Two dimensional correlation NIR spectroscopy analytical method based on density perturbation and matlab R2009 b data processing platform was employed for species identification of vegetable oils. In order to analyze the quality of olive oil, three categories of doped samples were prepared: olive oil adulterated with sunflower seed oil, olive oil adulterated with pomace olive oil, and olive oil adulterated with pomace olive oil and peanut oil. The main content and conclusions of the study are as follows:(1) In order to provide a new approach for on-line detection of vegetable oils, two-dimensional correlation NIR spectroscopy which chose n- hexane, acetone and toluene as concentration disturbance solvents was introduced. The important parameters, such as the contour parameter and disturbance concentration interval, were discussed to choose reasonable parameters.(2) Seven kinds of vegetable oils were selected and the NIR spectra and two-dimensional correlation NIR spectroscopy was analyzedto distinguish the species of vegetable oils. Results show that NIR spectra of these vegetable oils is hard to distinguish because of the similarity and overlap. While two-dimensional correlation NIR spectroscopy improves the spectral resolution, and makes the differences between each oil more intuitive and obvious.(3) The characteristics of two-dimensional correlation NIR spectra of soybean oil, pomace olive oil and olive oil under three different perturbation solvents of n-hexane, acetone and toluene were analyzed and compared to their respective. Results show that the peak information of two-dimensional correlation NIR spectra of the same vegetable oil was greatly influenced by the perturbation solvent variety and the better solvent is n-hexane.(4) In order to research the application effect of two-dimensional correlation NIR spectra analytical method to the quality analysis of olive oil, three categories of doped samples, namely, olive oil adulterated with sunflower seed oil, olive oil adulterated with pomace olive oil, and olive oil adulterated with pomace olive oil and peanut oil were researched. Result shows that two-dimensional correlation NIR spectra analytical method based on three kinds of disturbance solvents could clearly distinguish the three types of adulterated oils mentioned above with the better efficiency of n-hexane and acetone.(5) Different brands of olive oils under the same concentration disturbance solvent of toluene were compared. Result shows that the peak information of two-dimensional correlation NIR spectra of different brands of olive oils was extremely similar, which indicates that the brand doesn’t affect the peak information.