Browsing by Author "Garrido-Banuelos, G."
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- ItemThe impact of different tannin to anthocyanin ratios and of oxygen on the phenolic polymerisation over time in a wine-like solution(South African Society for Enology and Viticulture, 2019) Garrido-Banuelos, G.; Buica, A. S.; Sharp, E.; De Villiers, A.; Du Toit, W. J.Colour and phenolic stability during ageing are influenced by the levels of distinct classes of phenolics in young red wines. The ratios between different classes of phenolic compounds also determine the colour and phenolic development of red wines. The present study evaluated the impact of forced oxidation on different anthocyanin/tannin (A/T) extracts and its consequent effect on the colour and phenolic evolution over time. The results showed that higher contents of seed tannins could enhance phenolic polymer formation, especially in the presence of oxygen. The addition of oxygen seemed to favour certain polymerisation reactions between tannins, leading to higher concentrations of monomeric anthocyanins in solution. A slower oxygen consumption was also observed as the phenolic composition of the wine-like extract evolved over time.
- ItemImpact of time, oxygen and different anthocyanin to tannin ratios on the precipitate and extract composition using liquid chromatography-high resolution mass spectrometry(South African Society for Enology and Viticulture, 2019) Garrido-Banuelos, G.; Buica, A.; De Villiers, A.; Du Toit, W. J.Wine colour and phenolic stability over time are influenced by the amount and nature of phenolics in young wines. The ratio between different phenolic compounds can also be determinant in the colour and phenolic development of red wines. Three different anthocyanin to tannin ratios extracted in a wine-like system were saturated with oxygen several times during sample storage. A LC-HRMS method was used to evaluate the impact of a forced oxidation and of the different extracts on the wine-like composition and on the precipitate formed over time. The extract composition was found to be the most determinant factor for the precipitate formed. Time was also found to be a relevant factor according to the precipitate composition.
- ItemIs there a link between coffee aroma and the level of furanmethanethiol (FMT) in pinotage wines(South African Society for Enology and Viticulture, 2020) Garrido-Banuelos, G.; Buica, A. S.Over the years, Pinotage has found its way into the South African and international market. Producers have used the flavour potential of this “original” South African grape to produce different wine styles, one of them being the so-called “coffee-style Pinotage”. The current study aims to explain the impact of furanmethanethiol (FMT) on the characteristic coffee aroma of these coffee-style wines. Chemical and sensory evaluation, as well as data mining of the technical information available, was performed. Not all wines marketed as “coffee Pinotage” showed a high “coffee” rating. However, the results showed a good correlation between the aroma perception and FMT concentrations (R2 = 0.81). However, RV coefficients were low when comparing the coffee rating with the information provided on both the front and the back label, which shows that, in some cases, the use of the “coffee Pinotage” term was rather part of the marketing strategy.