1,630 research outputs found
NMR-Based Metabolomics for a More Holistic and Sustainable Research in Food Quality Assessment: A Narrative Review
Get PDFThe ability of nuclear magnetic resonance spectroscopy (NMR) to extract chemical information from a complex mixture is invaluable and widely described in literature. Many applications of this technique in the foodomics field have highlighted how NMR could characterize food matrices, and it can be used all along its “life chain”: from farm to fork and from fork to the digestion process. The aim of this review is an attempt to show, firstly, the potential of NMR as a method based on green chemistry in sample preparation, and then in characterizing the nutritional qualities of agri-food products (with particular attention to their by-products) from a sustainable point of view. For instance, the NMR-based metabolomics approach has been used to enhance the nutritional properties of bio-products waste naturally rich in antioxidants and prebiotics. The reintroduction of these products in the food supply chain as functional foods or ingredients answers and satisfies the consumer demand for more food with high nutritional quality and more respect for the environment
Fate of "pastazzo" and compost organic matter in soil as determined by isoelectric focusing and13c NMR spectroscopy
No full textAn incubation experiment on two different organic matrices mixed to a soil was carried out to monitor changes in the chemical composition of organic matter. Aim of the experiment was the knowledge of chemical changes occurring to organic matter added to soil due to stabilization processes. A control soil without any addition, a mixture of the same soil plus compost, and a mixture of the same soil plus "pastazzo" (an organic residue from industrial processing citrus fruits) were incubated in microcosms under controlled conditions of temperature and moisture. Sub-samples, taken from the microcosms at start of the experiment and fixed times during incubation, were analyzed to determine total organic carbon and humification parameters; then, they were extracted with NaOH and Na4P2O7, and the extracts were analyzed by CP-MAS 13C NMR and iso-electric focusing (IEF). IEF showed that the bandwidth of peaks produced by focused material on the right side of the profile increased by increasing incubation time, probably due to stabilization of the samples. The 13C NMR spectra of pastazzo seem to demonstrate its organic matter was completely mineralized by the gradual disappearance of its characteristic peaks, compared with those of the untreated soil. On the contrary, the spectrum characteristics of the compost were still recognizable after 2-years incubation, demonstrating higher stability. In all samples, an extra peak appeared after 6 months at nearly 170 ppm, corresponding to the area of the carboxylic groups, probably due to the production of esters. Both techniques can be used to profitably monitor transformations of organic residues when added to soil, specially by integration of the information obtained about the humification level suggested by IEF with the chemical characteristics of the samples determined by NMR
Abstract Book of the 12th International Conference on the Applications of Magnetic Resonance in Food Science
No full textXII International Conference on the Applications of Magnetic Resonance in Food Science: Defining Food by Magnetic Resonance.The first international conference was held in 1992 at the University of Surrey in Guilford, maintaining the long tradition of the Food MR Conference, the latest technical innovations and their current and potential applications to the understanding of food, their processing and stability, and their nutritional value, will be presented. Deployment of MR relaxometry, diffusometry and imaging, in both time-and frequency domain will be the focus of the session dedicated to the definition of food matter at the different scales, from the nanoscopic molecular level to the microscopic compartmental scale. New methods for decoupling and hyphenation, providing “quantitative experimental conditions”, will be presented during the q NMR session
Il trattamento del mito nell'Alessandra di Licofrone
No full textLa dissertazione della dott.ssa Silvana Ciampa ha per oggetto l'Alessandra, un ampio e singolarissimo carme in trimetri giambici del poeta ellenistico Licofrone di Calcide.
La dissertazione inizia con un'introduzione, nella quale si delinea la complessa struttura dell'Alessandra, si discutono i problemi connessi alla biografia di Licofrone e si argomenta che è impossibile inquadrare l'Alessandra in un genere letterario preciso.
La parte più ampia della dissertazione si articola in un insieme di letture ravvicinate di alcuni brani dell'Alessandra, attraverso le quali si scandagliano le peculiarità dell'approccio licofroneo al mito. Gli episodi presi in esame sono cinque. I primi tre provengono dalla sezione che riguarda il destino della famiglia di Alessandra/Cassandra dopo la caduta di Troia e sono incentrati sulle sorti di tre figlie di Priamo, cioè Laodice, Polissena e la stessa Cassandra. Gli altri due episodi sono invece delle digressioni, la prima dedicata alla contesa fra i Dioscuri e gli Afaridi e la seconda ad Anio e alle sue figlie (le Enotropi).
Di volta in volta si offre un'indagine dettagliata dei singoli miti, dove si ripercorrono le tappe principali che ne hanno segnato lo sviluppo diacronico e si pone particolare attenzione alle innovazioni introdotte dal poeta. Per ogni episodio la dott.ssa Ciampa fornisce innanzitutto il testo greco, seguito da una puntuale traduzione originale. Successivamente, oltre a esporre il mito presentato da Licofrone, la dott.ssa Ciampa ne ricostruisce organicamente il percorso, risalendo indietro nel tempo alle fonti verosimilmente utilizzate dal poeta e gettando in avanti lo sguardo sulle successive trattazioni della specifica vicenda mitica
Assessment of Astaxanthin Accumulation in Hepatocytes of Atlantic Salmon Fed Different Diets Using NMR Spectroscopy
Get PDFThis study aimed to assess the astaxanthin (Ax) accumulation in hepatocytes isolated from farmed Atlantic salmon fed different diets (rich marine, poor, poor with marine phospholipids (MPL) and poor with docosahexaenoic acid (DHA)). Nuclear magnetic resonance (NMR) spectroscopy was used for the Ax detection and quantification. The use of the 13C-enriched Ax allowed the assessment of short-time Ax metabolism. The substitution of fish oil and meal in fish feed on plant analogs and the addition of MPL caused further catabolism and decrease of Ax accumulation in hepatocytes from 17 to about 6 mg/kg or to almost zero in the case of DHA addition. Signals assignment of the native and 13C-enriched astaxanthin in acetone were performed using 1D and 2D NMR spectra.publishedVersio
Bond tests on concrete elements externally bonded with steel plates and assessment of bond strength models
No full textThe use of steel plates as externally bonded reinforcement for existing reinforced concrete (RC) elements can be still considered a reliable typology of strengthening intervention thanks to their relatively lower prices in comparison with fiber reinforced plastic materials, FRPs, largely used in the last decades, the ductile stress–strain behavior, and the high stiffness properties. Despite steel plates represented the first attempt of external strengthening for RC elements, design indications and practical execution rules concerning the use of such a technique nowadays are still very few. There is, indeed, a lack of experimental and theoretical studies in literature for predicting accurately the behavior of existing RC members externally strengthened with steel plates. In particular, special attention should be paid to the bond behavior at the steel–concrete interface, since it can strongly influence the performance of the strengthened elements. To this aim, an experimental campaign concerning bond tests on steel plates bonded over concrete elements and realized according to the single shear test set-up was carried out by the Authors. The experimental results are analyzed in the paper in terms of failure loads and modes, load–displacement behaviour, axial strain distributions along the steel plates, and distribution of shear stresses and slips. Then, the experimental results are compared with some well-known literature bond strength models for external FRP reinforcements in terms of failure load, transfer length and bond law. The comparisons with existing models in terms of debonding loads are developed also for an extended database of bond tests on steel plates available in literature and were prodromal to calibrate new coefficients specifically assessed for externally bonded steel plates
H NMR spectroscopy coupled with multivariate analysis was applied to investigate Italian cherry tomatoes metabolic profile
No full textNuclear magnetic resonance (NMR) spectroscopy, in combination with different chemometric methods, was widely used for metabolomic profiling in the geographical determination of food origin. In the present study, spectra data of cherry tomatoes, collected from Pachino (Sicily) and Sabaudia (Latium), were analyzed by principal component analysis (PCA), k nearest neighbors (kNN), and partial least-squares discriminant analysis (PLS-DA) in order to discriminate the samples according to their geographical provenance. The PCA analysis of 1H NMR spectra of Sabaudia cherry tomatoes showed significant differences linked to the production year: phospholipids had higher levels in 2004, but less amounts of polyunsaturated acids and lycopene were observed with respect to the year 2005. Despite the annual differences in 1H NMR metabolic profile of Sabaudia cherry tomatoes, using unsupervised (PCA) and supervised (PLS-DA, kNN) approaches, the geographical origin differentiation was obtained. In fact, the kNN algorithm correctly classified approximately 84% to 87% of Pachino samples and 77% of Sabaudia ones with recognition ability varied from 82% to 84.4% and prediction ability (CV) of 76.2% and 94.7%. The PC1 component, with 53% of total variance, greatly separated Pachino cherry tomatoes from Sabaudia ones and PLS-DA model showed a good degree of separation with recognition ability of 100% and prediction ability (CV) of 93% to 100%. PCA and PLS-DA combined analysis highlighted the most prominent spectral areas that well separated the two groups of samples. So, phytosterols were found discriminating compounds according to PCA and PLS-DA and differences in aroma components were observed mainly in PCA analysis
Application of HR-NMR for the Metabolic Kinetic Assessment of Red Mullet (Mullus barbatus) and Bogue (Boops boops) Samples during Different Temperature Storage
Get PDFFish freshness and quality can be measured through several indices that can be both chemical and physical. The storage temperature and the time that elapses following the catching of the fish are fundamental parameters that define and influence both the degree of freshness and nutritional quality. Moreover, they particularly effect the kind of fish we considered. In this research, it was observed how different temperatures of storage and shelf-life (+4 °C and 0 °C) may affect the metabolic profile of red mullet (Mullus barbatus) and bogue (Boops boops) fish samples over time, specifically observing the alteration of freshness and quality. In particular, a High-Resolution Nuclear Magnetic Resonance (HR-NMR)-based metabolomics approach was applied to study the metabolic profile changes that occur in fish spoilage. The HR-NMR spectroscopy data were useful for calculating a kinetic model that was able to predict the evolution of different compounds related to fish freshness, such as trimethylamine (TMA-N) and adenosine-5′-triphosphate (ATP) catabolites for the K-index. Furthermore, NMR in combination with chemometrics allowed us to estimate a further kinetic model able to represent the spoilage evolution by considering the entire metabolome. In this way, it was also possible to detect further biomarkers characterizing the freshness and quality status of both red mullets and bogues
Lettera di Alessandra
No full textUn ritratto critico dell'opera di Alessandra Carnaroli, autrice fra le più apprezzate delle ultime generazioni della poesia di ricerca. La sezione a lei dedicata, nel numero della rivista, contiene inoltre saggi di Cecilia Bello Minciacchi, Andrea Cortellessa, e Ivan Schiavone; e vari inediti dell'autrice. Il saggio è pubblicato con lo pseudonimo di Tommaso Ottonieri.A critical portrait of the work of Alessandra Carnaroli, author of the most appreciated in the latest generations of italian research poetry. Published under the pseudonym Tommaso Ottonieri
Selected letters of Alessandra Strozzi
No full textThe letters of Alessandra Strozzi provide a vivid and spirited portrayal of life in fifteenth-century Florence. Among the richest autobiographical materials to survive from the Italian Renaissance, the letters reveal a woman who fought stubbornly to preserve her family's property and position in adverse circumstances, and who was an acute observer of Medicean society. Her letters speak of political and social status, of the concept of honor, and of the harshness of life, including the plague and the loss of children. They are also a guide to Alessandra's inner life over a period of twenty-three years, revealing the pain and sorrow, and, more rarely, the joy and triumph, with which she responded to the events unfolding around her.This edition includes translations, in full or in part, of 35 of the 73 extant letters. The selections carry forward the story of Alessandra's life and illustrate the range of attitudes, concerns, and activities which were characteristic of their author
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