Pigments in Extra‐Virgin Olive Oil: Authenticity and Quality

Pigments, divided into carotenoids and chlorophyll derivatives, are responsible for the colour of extra‐virgin olive oil (EVOO). The concentration of pigments in EVOO depends on several factors, such as the maturity of olives before oil production, the cultivar and the geographic origin of olives. Pigments naturally degrade in olive oil (OO) during storage, and they may decompose due to light, temperature and oxygen exposure. The nature and concentration of pigments in EVOOs are different from seed oils, and this is a base of their use to reveal oil treatments and sophistication. In this chapter, the analytical methods, mainly chromatographic and spectroscopic, applied to identify and quantify pigments are overviewed. In particular, the applications of these methods to check the authenticity and the quality of extra‐virgin olive oil are discussed

Pigments in extra virgin olive oils produced in different mediterranean countries in 2014: Near UV-vis spectroscopy versus HPLC-DAD

Carotenoids and chlorophyll derivatives play a key role in Extra Virgin Olive Oils (EVOOs). Many factors, such as cultivar, geographic origin, maturity of olives, climate and storage conditions, influence the pigments’ content. The quantification of pigments is usually done by chromatographic techniques. However, recent works evidenced the potentialities of UV-visible-related methodologies. In this research, a selection of EVOO samples produced from olives harvested at the beginning of November 2014 in Greece, Tunisia, Italy and Spain, was investigated in terms of pigments by means of two methods. The first one is a recent approach based on the mathematical treatment of near UV-vis absorption spectra of olive oils to quantify in a fast, cheap and non-destructive way four main pigments, namely b-carotene, lutein, pheophytin A and pheophytin B. The second one is a more standard HPLC-DAD method. From the comparison between the two methods, we can conclude that the new near UV-vis approach gives reliable results, with good precision and high reproducibility. Pigments quantified by these two methods in EVOOs produced in four countries from different cultivars are analyzed by principal component analysis (PCA). Results indicate that pigments can be correlated to several factors such as ripeness stage, geographic origin and cultivars

The twist-bend nematic phase: translational self-diffusion and biaxiality studied by 1H nuclear magnetic resonance diffusometry

Recently, there has been a surge of interest in mesogens exhibiting the twist-bend nematic (NTB) phase that is shown to be chiral even though formed by effectively achiral molecules. Although it now seems to be clear that the NTB phase in the bulk is formed by degenerate domains having opposite handedness, the presence of a supramolecular heliconical structure proposed in the Dozov model has been contradicted by the Hoffmann et al. model in which the heliconical arrangement is replaced by a polar nematic phase. The evidence in support of this is that the quadrupolar splitting tensor measured in various experiments is uniaxial and not biaxial as expected for the twist-bend nematic structure. In this debate, among other evidence, the molecular translational diffusion, and its magnitude with respect to that in the nematic phase above the NTB phase, has also been invoked to eliminate or to confirm one model or the other. We attempt to resolve this issue by reporting the first measurements of the translational self-diffusion coefficients in the nematic and twist-bend nematic phases formed 1″,7″-bis-4-(4′-cyanobiphenyl-4′-yl) heptane (CB7CB). Such measurements certainly appear to resolve the differences between the two models in favour of that for the classic twist-bend nematic phase

Analysis of Extra Virgin Olive Oils from Two Italian Regions by Means of Proton Nuclear Magnetic Resonance Relaxation and Relaxometry Measurements

The interest in development of new non-destructive methods for characterization of extra virgin olive oils (EVOOs) has been increasing in the recent years. Among different experimental techniques, nuclear magnetic resonance (NMR) relaxation measurements are very promising in the field of food characterization and authentication. In this study, we focused on relaxation times T-1 and T-2 measured at different magnetic field strengths (namely, 2, 100, and 400 MHz) and H-1 NMR T-1 relaxometry dispersions directly on olive oil samples without any chemical/physical treatments. A large set of EVOO samples produced in two regions of Italy, Tuscany and Apulia, were investigated by means of H-1 NMR relaxation techniques. The relaxation studies reported here show several common features between the two sets of EVOO samples, thus indicating that relaxation properties, namely, the ranges of values of T-1 and T-2 at 2 and 100 MHz, are characteristic of EVOOs, independently from the cultivars, climate, and geographic origin. This is a promising result in view of quality control and monitoring

Multi-Analytical Approach to Characterize the Degradation of Different Types of Microplastics: Identification and Quantification of Released Organic Compounds

Microplastics and nanoplastics represent one of the major environmental issues nowadays due to their ubiquitous presence on Earth, and their high potential danger for living systems, ecosystems, and human life. The formation of both microplastics and nanoplastics strongly depends on both the type of pristine materials and the degradation processes related to biological and/or abiotic conditions. The aim of this study is to investigate the effect of two of the most relevant abiotic parameters, namely temperature and light, taken under direct control by using a Solar box, on five types of reference polymers: high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). A multi-analytical approach was adopted to investigate in detail the first steps of plastics degradation. Samples of plastic materials at different degradation times were analyzed by means of 1H NMR spectroscopy and thermal desorption gas chromatography mass spectrometry (TD-GC-MS) technique. Several minor molecular species released during degradation were consistently identified by both techniques thus providing a comprehensive view of the various degradation products of these five types of microplastics

Sensitivity of Proton NMR Relaxation and Proton NMR Diffusion Measurements to Olive Oil Adulterations with Vegetable Oils

Olive oils and, in particular, extra-virgin olive oils (EVOOs) are one of the most frauded food. Among the different adulterations of EVOOs, the mixture of high-quality olive oils with vegetable oils is one of the most common in the market. The need for fast and cheap techniques able to detect extra-virgin olive oil adulterations was the main motivation for the present research work based on H-1 NMR relaxation and diffusion measurements. In particular, the H-1 NMR relaxation times, T-1 and T-2, measured at 2 and 100 MHz on about 60 EVOO samples produced in Italy are compared with those measured on four different vegetable oils, produced from macadamia nuts, linseeds, sunflower seeds, and soybeans. Self-diffusion coefficients on this set of olive oils and vegetable oil samples were measured by means of the H-1 NMR diffusion ordered spectroscopy (DOSY) technique, showing that, except for the macadamia oil, other vegetable oils are characterized by an average diffusion coefficient sensibly different from extra-virgin olive oils. Preliminary tests based on both NMR relaxation and diffusometry methods indicate that eventual adulterations of EVOO with linseed oil and macadamia oil are the easiest and the most difficult frauds to be detected, respectively

Determinazione dei pigmenti e loro legame con parametri di qualità e autenticità dell'olio di oliva extravergine

Una delle caratteristiche peculiari dell’olio di oliva extravergine è il suo colore, che è dovuto alla presenza di una classe di composti minoritari: i pigmenti. La determinazione quantitativa dei pigmenti, ovvero delle concentrazioni dei carotenoidi, delle clorofille e dei loro derivati, può essere fatta utilizzando vari metodi sperimentali, suddivisi in metodi cromatografici e metodi spettroscopici. In questo lavoro si passeranno in rassegna questi due approcci, soffermandoci sugli ultimi sviluppi che hanno consentito di analizzare molti campioni di olio di oliva extravergine di diverse cultivar, provenienze geografiche e sottoposti a varie condizioni di conservazione. Questi studi sono stati utili ad individuare dei parametri associati al contenuto dei pigmenti in grado di definire l’autenticità e la qualità di un olio aprendo a interessanti prospettive applicative

Recent advancements in understanding thermotropic liquid crystal structure and dynamics by means of NMR spectroscopy

Recent progresses of NMR spectroscopy to the study of liquid crystals and related ordered systems are surveyed. Particular attention will be devoted to review suitably tailored NMR experiments and their applications on those systems (e.g. biaxial nematics, chiral smectics, V shaped mesogens, liquid crystalline elastomers) which are presently subject of active and innovative research. (C) 2013 Elsevier Ltd. All rights reserved

Olio di Oliva Extravergine Toscano: uno studio sul contenuto dei pigmenti e prospettive per un nuovo indice di qualità

Nel 2014 il nostro gruppo di ricerca ha messo a punto un nuovo metodo di analisi degli spettri di assorbimento nella regione ultravioletto-visibile (UV-vis) dell’olio di oliva extravergine per ricavare, in modo rapido e semplice, la quantità di alcuni pigmenti, i principali, che conferiscono a questo tipo di olio di oliva alcune importanti caratteristiche. Il contenuto in -carotene, luteina, feofitina A e feofitina B dell’olio di oliva extra-vergine è legato infatti alla qualità, alla freschezza e allo stato di conservazione del prodotto. In questo articolo, descriveremo alcune recenti applicazioni di questo metodo ad un campione rappresentativo di oli di oliva extravergine prodotti in Toscana da olive toscane. Verranno discussi alcuni parametri derivati dall’analisi degli spettri UV-vis che possono essere correlati alle diverse annate (dal 2011 al 2015), alle condizioni di conservazione e al “tempo di vita” dell’olio di oliva extravergine. Queste ricerche sono importanti non solo per caratterizzare uno dei prodotti agroalimentari più legati alla cultura e alla cucina mediterranea, ma anche per evidenziare eventuali frodi e adulterazioni che rischiano di minare l’autenticità dell’olio di oliva extravergine prodotto nella nostra regione