SciCombinator

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Concept: Burgundy

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The impact of co-fermenting white grape pomace (WP) and red grape pomace (RP) on the composition of interspecific hybrid wine was studied using the Vitis sp. ‘Frontenac’ and ‘Vidal’. The proanthocyanidin and anthocyanin content of the resulting wines were analysed by HPLC-fluorescence and UPLC-MS/MS, respectively. The CIELAB parameters and volatile compounds were analysed using spectrophotometry-UV and GC-MS-SPME, respectively. The WP addition increased the concentration of monomeric and oligomeric flavan-3-ols, and terpenes in the wines. The manipulation of the WP/RP ratio efficiently modulated the anthocyanin profile of the wines, resulting in faded red colour, a desirable achievement in hybrid red wine, which is usually perceived as too dark. An appropriate ratio (30% RP/6% WP) improved the colour stability of the wines without a significant impact on wine colour. Addition of WP proved to be a suitable tool to modulate the colour, the phenolic and volatile composition of interspecific hybrid wine.

Concepts: Red, Vitis vinifera, Wine, Oenology, Grape, Vitis riparia, Burgundy

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Though non-anthocyanin phenolics normally do not have red color, they affect the red color expression in the copigmentation of red wines. In this study, the influence of prefermentative addition of 300mg/L gallic acid and ellagic acid, as cofactors, on aging dry red wines had been systematically evaluated at the industrial scales from the perspectives of color, phenolic profiles and copigmentation effects of anthocyanins. Red wines made with these two compounds exhibited better color properties than the control, having better CIELAB chromatic parameters. Additionally, significantly higher levels of detectable anthocyanins and copigmented anthocyanin ratio had been observed. Wines with ellagic acid showed better chromatic properties and phenolic profiles than wines with gallic acid, as shown in previous theoretical results. Anti-copigmentation phenomenon was noticed and elucidated. These practical results confirmed that ellagic acid was the better cofactor, and would give more additional guidance for the production of high quality wine.

Concepts: Red, Wine, Tannin, Oenology, Anthocyanin, Raspberry, Wine tasting, Burgundy

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Evaluate the influence of two bleaching agents (16% carbamide peroxide-CP and 35% hydrogen peroxide-HP) on color and translucency of one resin composite (Filtek Z350 XT) in two opacities (enamel and dentin) previously aged in deionized water or red wine.

Concepts: Ammonia, Water, Red, Wine, Tooth enamel, Dental composite, Pykrete, Burgundy

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Copigmentation of anthocyanins accounts for over 30% of fresh red wine color, while during storage, the color of polymeric pigments formed between anthocyanins and proanthocyanidins predominates. Rosmarinic acid and natural extracts rich in hydroxycinnamic acids, obtained from aromatic plants (Origanum vulgare and Satureja thymbra), were examined as cofactors to fresh Merlot wine and the effect on anthocyanin copigmentation and wine color was studied during storage for 6months. An increase of the copigmented anthocyanins that enhanced color intensity by 15-50% was observed, confirming the ability of complex hydroxycinnamates to form copigments. The samples with added cofactors retained higher percentages of copigmented anthocyanins and higher color intensity, compared to the control wine, up to 3 months. However, the change in the equilibrium between monomeric and copigmented anthocyanins that was induced by added cofactors, did not affect the rate of polymerization reactions during storage.

Concepts: Polymer, Monomer, Wine, Oenology, Polymerization, Wine tasting, Burgundy, Wine color

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Monomeric anthocyanin contributions to young red wine color were investigated using partial least square regression (PLSR) and aqueous alcohol solutions in this study. Results showed that the correlation between the anthocyanin concentration and the solution color fitted in a quadratic regression rather than linear or cubic regression. Malvidin-3-O-glucoside was estimated to show the highest contribution to young red wine color according to its concentration in wine, whereas peonidin-3-O-glucoside in its concentration contributed the least. The PLSR suggested that delphinidin-3-O-glucoside and peonidin-3-O-glucoside under the same concentration resulted in a stronger color of young red wine compared with malvidin-3-O-glucoside. These estimates were further confirmed by their color in aqueous alcohol solutions. These results suggested that delphinidin-3-O-glucoside and peonidin-3-O-glucoside were primary anthocyanins to enhance young red wine color by increasing their concentrations. This study could provide an alternative approach to improve young red wine color by adjusting anthocyanin composition and concentration.

Concepts: Statistics, Concentration, Chemistry, Solution, Wine, Oenology, Burgundy, Wine color

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The aim of this study was to determine, by using a spectrophotometer device, the color stainability of two indirect CAD/CAM processed composites in comparison with two conventionally laboratory-processed composites after being immersed 4 weeks in staining solutions such as coffee, black tea and red wine, using distilled water as control group.

Concepts: Color, Caffeine, Red, Tea, Primary color, Distilled water, Laboratory equipment, Burgundy

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Once released from red grape skins, anthocyanins undergo various chemical reactions leading to the formation of more stable pigments such as pyranoanthocyanin, as well as other derivatives. Among these pigments, pyranoanthocyanins linked directly to flavanol dimers have been detected, and identified in aged Port wine but not in dry red wine. These pigments are very important as regard the wine colour evolution since they are involved in wine colour evolution and stabilization. During this investigation, the occurrence in dry red wine of two pyranomalvidinprocyanidin-dimer has been established by low and high resolution HPLC-UV-MS analysis. Moreover, the impact of acidity and oxygen levels on their formation in red wine has been estimated. After the four months of evolution the results showed that, for the same pH, the quantity of this pigment was correlated with oxygen concentrations. Moreover, for the same quantity of oxygen, the concentration of this pigment was related to the acidity level.

Concepts: Chemical reaction, Chemistry, Acetic acid, Wine, Oenology, Wine tasting, Burgundy

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The application of animal-derived proteins as wine fining agents has been subject to increased regulation in recent years. As an alternative to protein-based fining agents, insoluble plant-derived fibers have the capacity to adsorb red wine tannins. Changes in red wine tannin were analyzed following application of fibers derived from apple and grape, and protein-based fining agents. Other changes in wine composition, namely color, monomeric phenolics, metals and turbidity were also determined. Wine tannin was maximally reduced by application of an apple pomace fiber and a grape pomace fiber (G4) removing 42% and 38%, respectively. Potassium caseinate maximally removed 19% of wine tannin, although applied at a lower dose. Fibers reduced anthocyanins, total phenolics and wine color density, but changes in wine hue were minor. Proteins and apple fiber selectively removed high molecular mass phenolics, while grape fibers removed those of both high and low molecular mass. The results show that insoluble fibers may be considered as alternative fining agents for red wines.

Concepts: Wine, Tannin, Oenology, Polyphenol, Grape, Cabernet Sauvignon, Oak, Burgundy