Use of front face fluorescence for monitoring lipid oxidation during ageing of cakes.

Front face fluorescence spectroscopy coupled with chemometric tools was used as a useful tool for the monitoring of sponge cakes freshness, produced at the pilot scale, during ageing (i.e. 1, 3, 6, 9, 16, and 20days). The fluorescence emission spectra were acquired in the 340-490nm and 390-680nm after excitation at 325 and 380nm, respectively, while excitation spectra (250-390nm) were scanned after emission at 410nm. The primary and secondary products of lipid oxidation were also determined on the same cakes. The principal component analysis (PCA) applied to the each spectral collection obtained after excitation at 325 and 380nm and emission at 410nm allowed a clear discrimination of cakes according to their ageing. A high correlation between the intensity of fluorescence at 521nm and the p-anisidine values was observed since squared correlation coefficient of 0.73 was obtained. The results showed that fluorescence spectroscopy could be used as a powerful tool for the evaluation of cake freshness throughout storage.