Visible micro-Raman spectroscopy for determining glucose content in beverage industry

The potential of Raman spectroscopy with excitation in the visible as a tool for quantitative determina- tion of single components in food industry products was investigated by focusing the attention on glu- cose content in commercial sport drinks. At this aim, micro-Raman spectra in the 600-1600 cm À1 wavenumber shift region of four sport drinks were recorded, showing well defined and separated vibra- tional fingerprints of the various contained sugars (glucose, fructose and sucrose). By profiting of the spectral separation of some peculiar peaks, glucose content was quantified by using a multivariate statis- tical analysis based on the interval Partial Least Square (iPLS) approach. The iPLS model needed for data analysis procedure was built by using glucose aqueous solutions at known sugar concentrations as cali- bration data. This model was then applied to sport drink spectra and gave predicted glucose concentra- tions in good agreement with the values obtained by using a biochemical assay. These results represent a significant step towards the development of a fast and simple method for the on-line glucose quantifica- tion in products of food and beverage industry.