Использование 3D-спектров флуоресценции для идентификации подлинности масла виноградной косточки

Abstract

Falsification of grape seed oil causes serious damage to consumers and shows unfair competition in the market. 3D fluorescence spectroscopy was used to characterize oil flurophores and differentiate samples by identification criteria: method of preparation, raw material used, and manufacturer. During the study, 3D excitation-emission spectra of several samples of grape seed oil from various manufacturers available on the Russian market were obtained. One of the samples with confirmed production histories was used for comparison. The results of analysis of the obtained spectra by zones of maxima on the hypersurface of the absorption-emission matrix were correlated with individual fluorophores and their groups of functional ingredients of the oil, providing its physiological activity. The possibility of using the obtained data for identification of grapeseed oil samples and prompt detection of falsifications is shown. All samples were tested in hexane. It has been shown that genuine oil samples have distinctly differentiated regions of very high intensity on the hypersurface of the excitation-radiation matrix intensity with peaks characteristic of all isomers of tocopherols and tocotrienols with a predominance of the gamma isomer with an EEM maximum of 292/324 nm. There are also intense regions of absorption of carotenoids 325/453 nm and isomeric forms of chlorophyll 405–436/650–670 nm, the  form being the prevailing one. The absorption regions of procyanidins are intense 280 /316–324 nm; gallic acid 260/390 and coumaric acid 270/420. The uniqueness of the 3D fluorescence spectra for each oil and the formation of the resulting data pool in the form of a three-dimensional matrix allows them to be used for machine learning and the isolation of significant parameters by standard chemometrics.