| 1. |
- Garrido Banuelos, Gonzalo, et al.
(författare)
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The impact of different tannin to anthocyanin ratios and of oxygen on the phenolic polymerisation over time in a wine-like solution
- 2019
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Ingår i: South African Journal for Enology and Viticulture. - : South African Society for Enology and Viticulture. - 0253-939X .- 2224-7904. ; 40:2, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Garrido Banuelos, Gonzalo, et al.
(författare)
-
Is There a Link Between Coffee Aroma and the Level ofFuranmethanethiol (FMT) in Pinotage Wines?
- 2020
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Ingår i: South African Journal of Enology and Viticulture. - : Stellenbosch University. - 0253-939X .- 2224-7904. ; 41:2, s. 245-250
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Garrido Banuelos, Gonzalo, et al.
(författare)
-
Phenolic and sensorial evolution during bottle ageing of South African Shiraz wines with different initial phenolic profiles
- 2020
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Ingår i: South African Journal for Enology and Viticulture. - : South African Society for Enology and Viticulture. - 0253-939X .- 2224-7904. ; 41:1, s. 17-32
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this research was to evaluate the colour and phenolic evolution of Shiraz red wines made from the same vineyard, but with different initial phenolic profiles. Several vineyard-related variables were initially evaluated in a first vintage (2014), but grape ripeness was shown to be the most determining factor on most of the phenolics and the taste and mouthfeel of the wines. In the second vintage (2015), wines made from four different ripeness levels were aged up to 18 months and periodically analysed during this period. The results show how Shiraz wines with different initial phenolic profiles might develop differently over time during bottle ageing. In the second vintage, some of the colour and phenolic parameters of the wines were similar after completing the alcoholic fermentation (AF). However, these small differences between the wines became more noticeable over time, especially when comparing the wines made from the highest sugar level with the rest. These differences were especially noticeable in the polymeric fraction (polymeric phenols and polymeric pigments), with a larger number of polymeric forms found in the wines made from the ripest berries, and subsequently a larger formation of polymeric pigments. Differences in the wines' phenolic composition, and the differences in the alcohol content of the wines, also influenced the taste and mouthfeel evaluation of the wines, and these were maintained over time.
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