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Serdiana, Italy

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

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

Zara G.,University of Sassari | Mannazzu I.,University of Sassari | Del Caro A.,University of Sassari | Budroni M.,University of Sassari | And 4 more authors.
Australian Journal of Grape and Wine Research

Background and Aims: Interactions between different yeast species used as starters may lead to inconsistent results in mixed fermentations. The aim of this study was to assess the influence of different nutrients on the association between a wine strain of Candida zemplinina (CDZ1) and a commercial wine strain of Saccharomyces cerevisiae (EC1118) in mixed culture fermentations. Methods and Results: Laboratory-scale fermentations were carried out by inoculating CDZ1 and, after 3 days, EC1118 with the simultaneous addition of diammonium phosphate, yeast hulls, ergosterol and oleic acid, each provided separately. The addition of yeast hulls resulted in a higher cell population of CDZ1 and in a higher glycerol concentration of wine as compared with that of the other fermentations. Pilot-scale fermentations, carried out in a commercial winery, confirmed that the winemaking protocol based on the use of the mixed starters CDZ1/EC1118 with added yeast hulls results in wine with a higher glycerol content, more structured and persistent. Conclusions: Addition of yeast hulls improved the fermentative performance of the mixed starters CDZ1/EC1118. Significance of the Study: The high glycerol content of wines made with the combined use of yeast hulls and CDZ1/EC1118 mixed starters increases wine softness and body. © 2014 Australian Society of Viticulture and Oenology Inc. 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

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

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