Potential of synchronous fluorescence spectroscopy coupled with chemometrics to determine the heterocyclic aromatic amines in grilled meat

In this study, the potential of synchronous front-face fluorescence spectroscopy (SFS) coupled with chemometrics was investigated for the determination of heterocyclic aromatic amines (HAA) in cooked meat samples. Bovine meat samples (1-2 mm thick, 5 cm diameter) taken from Longissimus thoracis muscle were cooked at an average temperature of 237 °C for 5, 7 and 10 min. Four HAA (4, 8-DiMeIQx, MeIQx, IQx and PhIP) were determined on the cooked meat samples using classical LC-APCI-MS/MS method. In parallel, SFS spectra were recorded using a spectrofluorimeter on the same cooked meat samples in an excitation wavelength range of 250-550 nm using offsets of 20, 30, 40, …, 160 nm between excitation and emission monochromators. The three-dimensional synchronous fluorescence data set was analyzed using PARAFAC (parallel factor) analysis and N-PLS (n-way partial least square) regression method. PARAFAC analysis allowed capturing the fluorescence changes occurring in meat during cooking: the best model was obtained with 2 components (core consistency of 100% and explained variance of 99.2%). Whereas the loading profile of component 1 showed a maximum excitation at about 495 nm and an optimal offset of 60 nm, the loading profile of component 2 was characterized by a maximum excitation at 367 nm and an optimal offset of 90 nm. The results obtained using N-PLS regression showed good correlation between the spectral and analytical data: average recovery of 104% for 4, 8-DiMelQx, 102% for both MelQx and IQx, and 103% for PhIP were obtained. In conclusion this study indicates that SFS along with chemometrics has the potential to be used as a rapid and non-destructive technique for the determination of HAA contents in meat.