Olive Fruit Ripening Degree and Water Content Relationships with Phenolic Acids and Alcohols, Secoiridoids, Flavonoids and Pigments in Fruit and Oil

Olive drupe traits (i.e., ripening index and pericarp water content) and minor components (i.e., phenols and pigments in both fruit and oil) are important for human health and are affected by agronomic background. The aim of this study was to investigate the relationship between fruit traits, phenols, and pigments in samples derived from different soil and water management practices. Chromatographic (UHPLC-MS/MS) and spectroscopic (1HNMR and near UV-Vis spectroscopy) techniques were employed for the characterization of olive fruits and oils. The use of various techniques allowed the identification of interesting trace compounds. We observed that most of the fruit phenols (a total of 29 compounds) were correlated with the degree of ripening: most of the phenolic acids (and their derivatives), phenolic alcohols, and secoiridoids were negatively correlated, whereas the majority of the studied flavonoids were positively correlated. The relationship between the ripening index and fruit phenolic compounds appears to be dependent on the metabolic pathway that controls the synthesis of each individual compound. Conversely, the secoiridoids and pigments in olive oil showed a negative correlation with pulp moisture, probably because of the influence of the water content on the extractability and transfer in the oil phase of these minor components.

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 ¹H NMR relaxation and diffusion measurements. In particular, the ¹H NMR relaxation times, T₁ and T₂, 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 ¹H 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.

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 T1 and T2 measured at different magnetic field strengths (namely, 2, 100, and 400 MHz) and 1H NMR T1 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 1H 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 T1 and T2 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.

The effect of sourdough fermentation on Triticum dicoccum from Garfagnana: 1H NMR characterization and analysis of the antioxidant activity

The fermentation of Triticum dicoccum with sourdough enhances the nutritional aspects of the final product by the enrichment of several compounds with potential medical and biological activity, hence, could improve the health of consumers. This study analyzed the chemical composition of fermented spelt flour from Garfagnana (Province of Lucca, Tuscany) by ¹H Nuclear Magnetic Resonance (¹H NMR) spectroscopy and its in vitro antioxidant properties by FRAP and DPPH tests. Beyond this, the ex vivo CAA-RBC assay determined the cellular antioxidant activity on human erythrocytes under oxidative condition. Carbohydrate reduction was observed, while amino acids, organic acids and aromatic compounds with potential antioxidant activity increased during the fermentation time. Moreover, both in vitro and ex vivo outcomes showed an improved antioxidant profile. As a possible industrial application, the fermentation process adopted in this research could be reproduced on a large scale for the commercialization of the products by the food industry.

Effects of Extra Virgin Olive Oil and Apples Enriched-Dark Chocolate on Endothelial Progenitor Cells in Patients with Cardiovascular Risk Factors: A Randomized Cross-Over Trial

Background: Endothelial dysfunction has been associated to cardiovascular outcomes in patients with cardiovascular risk factors. Circulating endothelial progenitor cells (EPCs) play an important physiological role for their reparative potential of vascular integrity, but are numerically reduced and functionally impaired in patients with cardiovascular risks. This study assesses the effects of Extra Virgin Olive Oil (EVOO) and apple-enriched dark chocolate intake on the blood levels of EPCs. Methods: Thirty volunteers with cardiovascular risk factors, enrolled in a randomised, crossover, four-weeks trial, received a solid dark chocolate bar (40 g/day) containing 10% EVOO or 2.5% dry apples. Urine samples were analyzed for endogenous metabolites. Circulating EPCs levels, clinical data and anthropometric examinations were collected. Results: 26 volunteers (M/F:14/12, 51 ± 9 years of age) completed the study. Comparison of pre-post intervention revealed a significant increase in EPCs levels associated with EVOO-dark chocolate consumption. Most biochemical parameters were not significantly modified by both chocolates. Conclusions: This study shows that a daily consumption of a non fattening dose of dark chocolate enriched with EVOO improves blood levels of EPCs, a well known surrogate biologic marker for endothelial function.

15N-13C Dipole Couplings in Smectic Mesophase of a Thermotropic Ionic Liquid

Unique combination of ionic conductivity and anisotropic physical properties in ionic liquid crystals leads to new dynamic properties exploited in modern technological applications. Structural and dynamics information at atomic level for molecules and ions in mesophases can be obtained by nuclear magnetic resonance (NMR) spectroscopy through the measurements of dipole-dipole spin couplings. While 13C-1H and 15N-1H dipolar NMR spectra can be routinely acquired in samples with natural isotopic abundance, recording 15N-13C dipolar NMR spectra is challenging because of the unfavourable combination of two rare isotopes. In the present study, an approach to measure 15N-13C dipole-dipole NMR spectra in static liquid crystalline samples with natural abundance is introduced. We demonstrate that well-resolved spectra can be recorded within 10 h of experimental time using a conventional NMR probe and a moderately strong magnetic field. The technique is applied to a thermotropic smectic mesophase formed by an ionic liquid with imidazolium-based organic cation.

1H NMR and PCA-based analysis revealed variety dependent changes in phenolic contents of apple fruit after drying

Dry and fresh apples have been studied monitoring their polyphenolic profiles through ¹H NMR, antioxidant capacity and total polyphenol content. Six ancient and underutilized apple varieties (Mantovana, Mora, Nesta, Cipolla, Ruggina, Sassola) and a commercial one (Golden Delicious) were dried with an air-drying system at 45°C for 19h. Although some of their polyphenol constituents were lost during drying, the antioxidant capacity of some apple varieties remained higher compared to Golden Delicious. This result is very important for ancient and underutilized varieties that are not consumed on large scale as fresh product since they have low attractiveness, due to their ugly appearance. Combining quantitative NMR spectroscopy with principal component analysis we have identified and quantified several polyphenols (such as catechin, epicathechin, and chlorogenic acid) that are important to establish the nutraceutical value of the different investigated apple varieties.

A practical tutorial to set up NMR diffusometry equipment: application to liquid crystals

NMR diffusometry is nowadays a well-established and powerful technique to investigate molecular translation in fluid materials. Standard NMR diffusometry approaches are based on pulsed field gradients generated by specific hardware and specially designed NMR probes. Here, we present an alternative set-up that exploits the static gradient present in the fringe field of any commercial superconducting magnet. This stray field diffusometry technique can be particularly useful to study diffusional processes in fast-relaxing and slow-diffusing systems, such as thermotropic liquid crystals, ionic liquids and polymer melts.

Extraction of pigment information from near-UV vis absorption spectra of extra virgin olive oils

This work reports a new approach to extract the maximum chemical information from the absorption spectrum of extra virgin olive oils (EVOOs) in the 390-720 nm spectral range, where "oil pigments" dominate the light absorption. Four most important pigments, i.e., two carotenoids (lutein and β-carotene) and two chlorophylls (pheophytin-a and pheophytin-b), are chosen as reference oil pigments, being present in all the reported analytical data regarding pigments of EVOOs. The method allows the quantification of the concentration values of these four pigments directly from the deconvolution of the measured absorption spectrum of EVOOs. Advantages and limits of the method and the reliability of the pigment family quantification are discussed. The main point of this work is the description of a fast and simple method to extract of such information in less than a minute, through the mathematical analysis of the UV-vis spectrum of untreated samples of oil.

Synthesis, chiroptical properties and density functional theory calculations of 3,3'-biphenyl-2,2'-bitropone

The synthesis of new bitropone derivatives, namely, 3,3'-biphenyl-2,2'-bitropone and 7,7'-biphenyl-2,2'-bitropone, are reported. Isolation of enantiomers arising from restricted rotation around the C-C bond connecting the tropone moieties was attempted by means of chiral high performance liquid chromatography (HPLC). No separation was obtained for 7,7'-biphenyl-2,2'-bitropone. For 3,3'-biphenyl-2,2'-bitropone, difficulties were encountered because of the low separation factor of the peaks and the presence of a rapid racemization process. However, quantitative chiroptical data on the antipodes were obtained by linking a circular dichroism (CD) spectrometer and a UV-vis spectrophotometric detector in series to the HPLC instrument. The analysis of the CD and UV-vis spectra in terms of absolute conformations was done with the help of theoretical calculations performed at the Density Functional Theory (DFT) level. The most stable conformations of the 3,3'-biphenyl-2,2'-bitropone in its ground state were obtained. Starting from these minimum energy conformations, it was possible to compute theoretical CD and UV absorption spectra that fit well with the experimental ones. From this comparison the absolute configuration to the antipodes was assigned. Finally, the effect of the presence of the two lateral phenyl substituents on the structure of the bitropone and hence on the CD spectrum is discussed.

Chemical–physical and in vivo evaluations of a self-assembling amphiphilic peptide as an injectable hydrogel scaffold for biomedical applications

The self-aggregation and gelation of an amphiphilic peptide (C17H35CONH–A4G3ERGD, peptide amphiphile) were studied by light scattering, viscometry, nuclear magnetic resonance diffusometry, and atomic force microscopy. The peptide amphiphile critical aggregation concentration was evaluated to be 16 and 60 µM by light scattering and viscometry, respectively. The observed difference was attributed to the larger sensitivity of the latter technique to the presence of long fibrils. The addition of one equivalent or more of divalent cations (Ca2+ and Mg2+) to peptide amphiphile formed dense incoherent hydrogels. Based on the atomic force microscopy and nanoindentation data, both the hydrogel morphology and stiffness were independent of the cation type and peptide amphiphile concentration. However, gel stiffness increased on increasing Ca2+/peptide amphiphile molar ratio while a parallel decrease in the apparent water diffusion rate was observed by nuclear magnetic resonance diffusometry. The dispersions of endothelial progenitor cells in the peptide amphiphile hydrogels were evaluated in vivo on a rat tissue hypoxia model. Significant capillary formation at the injection site was observed by tissue appearance and histological examination, which indicated endothelial progenitor cell/peptide amphiphile hydrogel-enhanced angiogenesis in ischemic tissue.

Dynamics of partially oriented L-phenylalanine-d(8) in the CsPFO/H(2)O lyotropic system via (2)H NMR relaxation studies

Dynamics of the l-phenylalanine-d(8) has been here investigated by analyzing the (2)H NMR spin-lattice relaxation times of this selectively deuterium enriched amino acid diluted in the cesium pentadecafluorooctanoate/water (CsPFO/H(2)O) lyotropic system both in the nematic (N(+)(D)) and in the lamellar (L(D)) phases. Information on the internal and overall molecular motions as well as on collective motions has been achieved by a global fitting procedure. The dynamic processes affecting this probe molecule reflect its particular conformational and interaction properties with respect to the lyotropic environment. The best reproduction of the experimental data is obtained by assuming free internal reorientations of the benzylic moiety, which results in diffusion constants of the same order of magnitude of the overall molecular spinning motion. Moreover, the contribution of collective motions (order director fluctuations and layer undulations) is estimated to be greater than that commonly observed by other techniques in lyotropic systems.

NMR investigation of the dynamics of banana shaped molecules in the isotropic phase: a comparison with calamitic mesogens behaviour

The first translational self-diffusion NMR measurements in the isotropic phase of banana-shaped liquid crystals are reported. In this paper, two banana-shaped mesogens, having a similar molecular structure and showing a nematic phase, have been investigated by means of translational self-diffusion NMR, (2)H NMR spin-spin and (1)H NMR spin-lattice relaxation measurements in the isotropic phase. While (1)H diffusion and (2)H relaxation times reveal a peculiar slow dynamic behaviour of banana-shaped mesogens compared with calamitic mesogens, the (1)H relaxation times seem to be affected by fast dynamics only. The origin of these dynamic features is discussed in terms of overall and internal molecular motions, in the frame of recent speculations concerning the formation of molecular clusters or aggregates in the isotropic phase of banana-shaped liquid crystals.

Smectic order parameters from diffusion data

Microcanonical molecular dynamics simulations have been performed in the smectic A phase of an elementary liquid-crystal model. Smectic order parameters and diffusion coefficients along directions parallel and perpendicular to the director have been calculated during the same trajectory for a number of state points. This has permitted the satisfactory testing of a procedure, adopted in the analysis of experimental self-diffusion coefficients, leading to an estimate of the temperature dependence of the smectic order parameters. This methodology has been then confidently applied to two smectogenic thermotropic liquid crystals belonging to the 4,4(')-di-n-alkyl-azoxybenzene series. The derived smectic order parameters are larger for the homologue compound with the longest alkyl chains. This is consistent with the well-established increased tendency, for members of a homologue series, to form a smectic phase as their alkyl chains become longer.

Translational self diffusion anisotropy in the smectic A phase measured by a static fringe field gradient 1H NMR diffusometry approach

Self diffusion along the phase director in the nematic phase and parallel to and across the layer in the smectic A phase of the OAB smectogen has been measured exploiting a static fringe field gradient 1H NMR diffusometry approach.

Multidimensional imaging using combined stray field and pulsed gradients

The paper describes an advance in stray field imaging (STRAFI) whereby images of planar samples can be obtained in the stray field of a superconducting magnet without the need for sample rotation. This is achieved by using the static stray magnetic field gradient in combination with pulsed orthogonal gradients. Results of both two- and three-dimensional implementations of the experiment are presented and discussed. An extension to diffusion-weighted imaging is introduced. The technique is expected to prove particularly useful in experiments where high resolution is required in only one direction while lower resolution is acceptable in the orthogonal directions, such as in studies of the drying and curing of paints and varnishes. Arising from the work, a new method for accurately calibrating the radiofrequency pulse width in stray field is found.