Monitoring the identity and the structure of soft cheeses by fluorescence spectroscopy

Soft cheeses exhibit a wide range of textures and, as a consequence, of structures. The objective of the present study was to investigate intrinsic fluorophores of cheese in order to discriminate between eight different soft cheeses. Protein tryptophan emission spectra and vitamin A excitation spectra were recorded directly on cheese samples using front face fluorescence spectroscopy. The eight soft cheeses were discriminated using their spectra by applying multivariate statistical methods such as principal component analysis and factorial discriminant analysis. From the tryptophan fluorescence data set, a good classification was observed for 95% and 92% of the principal and test samples, respectively. A better classification (96% and 93% for principal and test samples) was obtained from the vitamin A spectra. The spectral pattern associated with the principal components provides characteristic wavelengths which are the most suitable for separating the spectra. They allow information on the protein structure at the molecular level to be derived, in relation with cheese texture. cheese / identification / structure / fluorescence / protein Rsum -La spectroscopie de fluorescence frontale pour identifier et caractriser la structure de fromages pte molle. Les fromages pte molle prsentent une large gamme de texture et, en consquence, de structure. L'objectif de cette tude tait d'valuer le potentiel des fluorophores intrinsques du fromage dans la discrimination de 8 types de fromages pte molle. Les spectres d'mission des tryptophanes de protines et les spectres d'excitation de la vitamine A ont t enregistrs directement sur des fromages au moyen de la fluorescence frontale. L'analyse des collections de spectres par des mthodes statistiques multidimensionnelles telles l'analyse en composantes