Determination of Ethanol Concentration in Chinese Rice Wine by Dispersive Raman Spectroscopy

The suitability of rapid determination of ethanol content in Chinese rice wine by dispersive Raman spectroscopy was investigated in this study for the first time. The measurement was employed using a 785 nm laser, and a total of 30 samples of Chinese rice wine were analyzed. As calibration model for ethanol content, a partial least squares (PLS) regression was applied. The accuracy of the Raman calibration model was estimated using the root mean square error (RMSE) of calibration and validation and the correlation coefficient (R2) between actual and predicted values. The calibration curve of actual ethanol % obtained by the reference predicted values based on Raman spectra was established for different spectral regions. The whole spectral window was found to be useful for the prediction of the ethanol content. High R2 and small RMSE values for calibration and validation could be obtained, respectively. The results indicated that dispersive Raman spectroscopy could be used as an easy and rapid tool to determine ethanol concentration in Chinese rice wine.