Analysis And Application Of Fluorescence Characteristics Of Several Kinds Of Aged Liquors

Aged liquor is storaged for a certain period of time. Because of its soft and mellow taste,aged liquor has been widely favored by consumers. The vintage will have a direct impact on the price of liquor, therefore, the determination of vintage of liquor is of great significance. In our project, FLS920 fluorescence spectrometer is used to measure three-dimensional fluorescence spectra and the fluorescence lifetime of aged liquor.At the same time, the fluorescence spectra of aged liquor are analyzed and the vintage of that liquor is determined.In our project, the three-dimensional fluorescence spectra of aged liquor in three different brands are analyzed to find the difference of aged liquor. The fluorescence intensity of the threedimensional fluorescence spectrum of Luzhou-flavor aged liquor increases at the 410 nm peak position with the growth of vintage of liquor. The fluorescence intensity at 540 nm peak position of the three-dimensional fluorescence spectrum of sesame-flavor aged liquor increases with the growth of vintage of liquor. The fluorescence intensity at 530 nm and 420 nm peak position of the three-dimensional fluorescence spectrum of Fung-flavor aged liquor increases with the growth of vintage of liquor. And the content of ethyl caproate in some Luzhou-flavor liquor is quantitatively determined.The way of determining the vintage of the same brand of liquor by three-dimensional fluorescence spectrum conbined with Chebyshev distance is set up. By measuring the threedimensional fluorescence spectrum of a brand of sesame flavor aged liquor. Data is processed by the principal component analysis after preprocessing of wavelet transform. The polynomial function is established based on the difference of vintage of liquor and the Chebyshev distance of spectra of liquor in different vintages that are calculated by principal component score. The results show that the vintage error of the liquor is predicted by the fifth order polynomial function is small.In order to develop rapid and accurate method of the identification of aged liquor. The way of three-dimensional fluorescence spectroscopy combined with partial least-squares regression and quadratic optimal regression is set up to measure the vinatge of a certain brand of liquor. Average fluorescence intensity,standard deviation of numerical matrix and maximal relative fluorescence intensity of the three-dimensional fluorescence spectra of the liquor in different vintages are extracted to construct the polynomial function. Two prediction models for the vintages of aged liquors are established combined with partial least square regression and quadratic optimal regression,respectively. The vintages of aged liquors of 1989、1994、1996、2002、2003、2005、2006、2009、2011 are predicted by the two models above, and the average absolute errors are 0.68 and 0.56,respectively. The results show that the abovedescribed methods can effectively determine the vintages of aged liquors. The nonlinear model has a better precision than the linear model.