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Deiana M.,University of Cagliari | Loru D.,University of Cagliari | Incani A.,University of Cagliari | Rosa A.,University of Cagliari | And 8 more authors.
Food Chemistry | Year: 2012

One of the most important sites of polyphenol action seems to be in the gastrointestinal system before absorption. We investigated the ability of three wine phenolic extracts, obtained from grape varieties grown in Sardinia, Cannonau (red), Vermentino and Malvasia (white), to exert an antioxidant action against tert-butyl hydroperoxide (TBH)-induced oxidative damage to Caco-2 cell monolayers as a model system of the human intestine. TBH treatment caused the disruption of epithelial integrity, measured as transepithelial electrical resistance, and markers of the peroxidation process of membrane lipids, MDA, fatty acid hydroperoxides and 7-ketocholesterol. All wine extracts were able to counteract the oxidising action of TBH and, in spite of the differences in phenolic composition, exerted a comparable activity. Our findings point out a direct antioxidant action of the wine extracts on enterocytes exposed to oxidising species and further support the opinion that total phenolic content is not essential for antioxidant activity. © 2012 Elsevier Ltd. All rights reserved. Source

Floris T.,Saras Ricerche e Tecnologie Spa | Filippino G.,Saras Ricerche e Tecnologie Spa | Scrugli S.,Saras Ricerche e Tecnologie Spa | Pinna M.B.,Argiolas SpA | And 4 more authors.
Journal of Supercritical Fluids | Year: 2010

A process is proposed to selectively extract polyphenols and anthocyanins from lyophilized grape residues. The compounds of interest are first extracted from the vegetable matter, using a tartaric buffer to avoid extract degradation due to polyphenol oxidase, hydrolysis or esterification and to eliminate part of the interfering compounds (mainly sugars). Then, they are selectively adsorbed on a C18 column and desorbed using methanol. The methanolic solution is processed by supercritical antisolvent extraction (SAE) at various process conditions. The optimized result is a powderous, solventless precipitate that, in the case of Cannonau cultivar, contains 33 polyphenols and 7 anthocyanins. The overall content of polyphenols recovered is of 521 mg/kg and the total content of anthocyanins is of 15542 mg/kg of treated material. The most abundant compounds extracted are cathechin (113.9 mg/kg), epicathechin (96.9 mg/kg), epicathechin gallate (101.6 mg/kg) for polyphenols and malvin acetate (1304 mg/kg) and malvin cumarate (9256.9 mg/kg) for anthocyanins. SAE processing confirms to be very effective in producing solventless selective extracts, avoiding their degradation. © 2010 Elsevier B.V. Source

Masili A.,University of Cagliari | Puligheddu S.,Saras Ricerche e Tecnologie Spa | Sassu L.,Saras Ricerche e Tecnologie Spa | Scano P.,University of Cagliari | Lai A.,University of Cagliari
Magnetic Resonance in Chemistry | Year: 2012

In this work, we report the feasibility study to predict the properties of neat crude oil samples from 300-MHz NMR spectral data and partial least squares (PLS) regression models. The study was carried out on 64 crude oil samples obtained from 28 different extraction fields and aims at developing a rapid and reliable method for characterizing the crude oil in a fast and cost-effective way. The main properties generally employed for evaluating crudes' quality and behavior during refining were measured and used for calibration and testing of the PLS models. Among these, the UOP characterization factor K (KUOP) used to classify crude oils in terms of composition, density (D), total acidity number (TAN), sulfur content (S), and true boiling point (TBP) distillation yields were investigated. Test set validation with an independent set of data was used to evaluate model performance on the basis of standard error of prediction (SEP) statistics. Model performances are particularly good for K UOP factor, TAN, and TPB distillation yields, whose standard error of calibration and SEP values match the analytical method precision, while the results obtained for D and S are less accurate but still useful for predictions. Furthermore, a strategy that reduces spectral data preprocessing and sample preparation procedures has been adopted. The models developed with such an ample crude oil set demonstrate that this methodology can be applied with success to modern refining process requirements. Copyright © 2012 John Wiley & Sons, Ltd. Source

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