Synchronized scanning fluorescence spectra method for grape seed oil authenticity identification

Fluorescence spectroscopy (SF spectroscopy) is one of the most sensitive and inexpensive methods for operational screening of counterfeits. The article analyses the method of simultaneous emission and excitation spectrum scanning for the identification of direct-press grape seed oil. Four samples of Russian-made grape seed oil were analyzed by SF spectroscopy method. The results showed that SF spectroscopy allows not only to identify individual compounds in the structure of the grape seed oil matrix, but also to separate their isomers. The most informative data were obtained at an energy degradation value (∆hem–∆hexcl) of from to 30 and 60 nm. At the same time, in the samples of genuine oils, there was a clear differentiation of maxima for tocopherols and tocotrienols λmax = 287 nm and 305 nm, respectively. At ∆h30 and λmax = 283 nm and 305 nm at ∆h40 nm, no peak separation occurred in the adulterants. Similar band separation was observed for the isomers of chlorophyll  (λmax = 633nm) and chlorophyll β (λmax = 668 nm) at ∆h40 nm. There were no peaks of chlorophyll, carotenoids, and cinnamic acids in the falsified samples. The most informative was the analysis of the full spectrum of synchronous fluorescence scanning (TSFS) with a scan step of ∆h10. Thus, SF spectroscopy allows operational screening of counterfeiting grape-seed oil and analogous food products.