Rapid evaluation and discrimination of γ-irradiated carbohydrates using FT-Raman spectroscopy and canonical discriminant analysis

Chemical changes induced by gamma irradiation of selected sugar systems - honey and fructose - were investigated through their molecular fingerprint using Fourier transform Raman spectroscopy (FT-Raman). Generalized two-dimensional (2-D) correlation spectroscopy was applied to FT-Raman spectra of the control and 17 kGy irradiated fructose to elucidate changes in the chemical structure upon irradiation. The irradiation induced changes in the ring (below 700 cm ^-1) and conformational structure (800-1500 cm^-1) of fructose were identified by means of a 2-D FT-Raman correlation spectroscopy. The irradiation damage depicted from the C-H stretch region (2800-3000 cm ^-1) of the FT-Raman spectra of honey was used to develop a pattern recognition model for classifying honey based on the irradiation dose. A hybrid partial least squares (PLS)-canonical variate analysis (CVA) with the optimum number of factors from PLS was used for rapid discrimination of honeys irradiated at 1, 5, 10 or 17 kGy. The present study demonstrated that FT-Raman spectroscopy, together with chemometrics, could be a rapid tool for classification of foodstuffs with high sugar content and provides a viable option to explore radiation-induced modifications to sugar systems subjected to irradiation processing.