Front-face fluorescence spectroscopy: A new tool for control in the wine industry

PARAllel FACtor Analysis (PARAFAC) in combination with front-face fluorescence spectroscopy was applied in the evaluation of wine samples according to their appellation and ageing condition. Excitation-emission matrices (EEMs) were obtained from front-face fluorescence measurements of untreated wine samples between 245–345 and 300–500 nm for excitation and emission respectively. Firstly, PARAFAC was applied for exploratory analysis and the four obtained components were assigned to different fluorophores present in the wine samples according to bibliographic data. Further interpretation of PARAFAC-score values allows the discrimination and clustering of wine samples belonging to different appellations. Therefore when plotting the scores of second PARAFAC component against the third a good separation between Rioja and Ribera del Guadiana samples is achieved. The effect of ageing was also studied using the same methodology. An improved discrimination between Rioja and non-Rioja samples for crianza and reserva wines compared to young wines was found.