Direct Determination of Unsaturation Level of Milk Fat Using Raman Spectroscopy

Abstract

We have demonstrated the potential of visible Raman spectroscopy in combination with chemometric analysis as a fast and simple tool for the determination of the unsaturation level of milk fat. The Raman measurements have been performed directly on liquid milk and on fat extracted from liquid milk. The Raman spectra taken from the extracted fat showed a higher resolution. The spectra directly obtained from the milk samples had some fluorescence background but nevertheless yielded the desired information. For calibration purposes, the iodine value (IV) was determined in all cases in order to evaluate the unsaturation level of the investigated samples. Two separate calibration models have been constructed; one for the milk samples and the second one for the extracted fat. The accuracy of these calibration models was estimated using the root mean square error of calibration and validation (RMSE) and the coefficient of determination ( R 2 ) between actual and predicted values.