Near UV-Vis and NMR Spectroscopic Methods for Rapid Screening of Antioxidant Molecules in Extra-Virgin Olive Oil.

Giulia Vicario,Valentina Domenici,Luca Sebastiani,Mario Cifelli,Alessandra Francini

doi:10.3390/antiox9121245

Giulia Vicario, Valentina Domenici + Show 3 more

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https://doi.org/10.3390/antiox9121245

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Abstract

Several spectroscopic techniques have been optimized to check extra-virgin olive oil quality and authenticity, as well as to detect eventual adulterations. These methods are usually complementary and can give information about different olive oil chemical components with bioactive and antioxidant properties. In the present work, a well-characterized set of extra-virgin olive oil (cultivar Frantoio) samples from a specific area of Tuscany (Italy) were investigated by combining near UV-Vis absorption spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) to identify and quantify different chemical components, such as pigments, secoiridoids and squalene, related to the nutritional and quality properties of olive oils. Moreover, the pigmentation index of olives, organoleptic and sensory properties, total phenolic compound contents and the lipidic fractions of olive oils were investigated. The results obtained are, finally, compared and discussed in order to correlate several properties of both olives and olive oils with specific features of the cultivation area.

Highlights

Spectroscopic methods are widely considered efficient tools for food in terms of oxidative stability and quality but, authentication, due to their high sensitivity, rapidness and possibility to perform analyses directly on the sample without previous treatments [1,2,3]
The pigmentation index was lower in the olive group 2 compared to olive groups 1 and 3, but none of these differences was significant
extra-virgin olive oil (EVOO) 1 and EVOO 3 obtained from olives with pigmentation index (Pi) = 6.5 and Pi = 5.6, respectively, are distributed on the top side of the graph, while the EVOO 2 obtained from olives with Pi = 5.3 is distributed on the bottom side of the graph

Summary

Introduction

Spectroscopic methods are widely considered efficient tools for food in terms of oxidative stability and quality but, authentication, due to their high sensitivity, rapidness and possibility to perform analyses directly on the sample without previous treatments [1,2,3]. Compared with standard chromatographic methodologies, spectroscopic techniques are often less time-consuming and less expensive For these reasons, in the last decade, many spectroscopic techniques were optimized and used in combination with multivariate techniques to food analysis in terms of chemical composition, trace contaminant determinations, food quality and authenticity and fraud identifications [4,5]. A very interesting review about the state-of-the-art of nuclear magnetic resonance methods applied to the quality assessment of a large variety of food and agricultural products was just published [8]. All these considerations are valid for the case of olive oil. A recent review about rapid and innovative instrumental approaches for oil quality assessment was published by Valli et al [11]

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