A Method for Fast-Acting Analysis of Quality of Unknown Olive Oils Using Fluorescence Spectroscopy

Abstract

AbstractFluorescence spectroscopy is a widely used method from biology to agriculture and from the natural to the technical sciences. It is convenient and easy to be applied on samples of plant and animal origin.Since the fluorescence signal is often very weak and is emitted in all directions, in order to avoid saturation of the detector, the useful fluorescence signal is measured in a direction 45° to the excitation radiation. For the purposes of the study four laser wavelengths - 370 nm, 395 nm, 450 nm and 425 nm, are chosen to excite the samples.For first time several types of olive oils from three regions of Europe - Greece, Italy and Spain, are object of investigation. This study examines different types - extra virgin, virgin, olive pomace oil and olive oils (for characterization of the olive oil types COI/OT/NC no. 1 Resolution No. RES-2/91-IV/04 and COI/T.15/NC no 3–25 (revised June 2003) standards are used). Data are obtained for extra virgin olive oil, virgin olive oil, olive pomace oils and cold-pressed olive oil which originate from the model oil was chosen from different producers. Analysis of the data shows that extra virgin olive oils have a pronounced fluorescence peak of 680 nm followed by 720 nm while the olive pomace oil and cold-pressed olive oils are shifted to the left i.e., about 600 nm with symmetrically arranged additional peaks.Fluorescence spectra for unknown olive oils were obtained. The data show that the method using fluorescence spectroscopy, developed by the authors, allows the classification of the type of studied olive oil based on its characteristic fluorescent spectrum.KeywordsOlive oilFluorescence spectroscopy