Fluorescence spectroscopy coupled with factorial discriminant analysis technique to identify sheep milk from different feeding systems

Rapid measurements of milk properties and discrimination of milk origin are necessary techniques for quality control of milk products. The present study was undertaken to evaluate the potential of using front face fluorescence spectroscopy (FFFS) and synchronous fluorescence spectroscopy (SFS) for monitoring the quality of forty-five ewe’s milk samples originating from different feeding systems. Physico-chemical analyses and fluorescence spectra were conducted on samples during lactation periods (the first 11 weeks). The principal component analysis (PCA) separately applied to the physico-chemical and fluorescence spectral data showed only small discrimination between milk samples based on lactation periods and diet compositions. Similar results were obtained by separately applying factorial discriminant analysis (FDA) on each technique. In a second step, concatenation technique were applied to FFF spectra acquired after excitation set at 250, 290, 380 nm and emission set at 410 nm. Results obtained showed a good discrimination among milk samples with regard to feeding systems given to the ewes throughout the lactation periods. In addition, a better discrimination was observed with FFFS than with SFS.