Exposure of grapes to smoke of vegetation with varying lignin composition and accretion of lignin derived putative smoke taint compounds in wine

Kelly, David; Zerihun, Ayalsew; Singh, Devinder; Eckstaedt, Christiane Vitzthum von; Gibberd, Mark; Grice, Kliti; Downey, Mark O.

doi:10.1016/j.foodchem.2012.05.036

Cited by 30 publications

(75 citation statements)

References 39 publications

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“…These vineyards are typically located in close proximity to forests and agricultural areas, and bushfire emissions that may contribute to the accumulation of smoke compounds in wine grapes can arise from remnant native forest, plantations and farmland vegetation. Two fuels, the softwood species radiata pine (Pinus radiata D. Don) and a pasture grass, wild oats (Avena fatua L.) were collected and prepared as described in Kelly et al (2012) to compare uptake of smokeborne phenols between cultivars.…”

Section: Fuel Types and Fuel Compilationmentioning

confidence: 99%

Winemaking practice affects the extraction of smoke‐borne phenols from grapes into wines

Kelly

Zerihun

Hayasaka

et al. 2014

Australian Journal of Grape and Wine Research

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Background and Aims: Exposure to smoke and uptake of taint imparting phenols in grapes and wines is a significant problem in bushfire-prone regions of Australia and other countries. The effects of smoke exposure on taint occurrence in wines, however, can be variable. This study assessed the influence of cultivar on uptake and accumulation of smoke-borne phenols in grapes and of subsequent processing and winemaking methods on extraction of phenols into wines. Methods and Results: Smoke-exposure experiments were conducted in commercial vineyards of Chardonnay, Merlot and Sauvignon Blanc 14 days after the onset of veraison. At maturity, grapes were harvested for winemaking, which included malolactic fermentation (MLF) for Merlot. Volatile and glycoconjugated phenols were determined in grapes and the resultant wines. All cultivars had a similar concentration of smoke-derived total phenols in their grapes. The apparent extraction of total phenols from grapes into wines, however, differed markedly among the three traditional winemaking methods. Red winemaking (Merlot) with skin contact extracted 88% of total grape phenols, whereas white winemaking either by crushing before pressing (Sauvignon Blanc) or by whole-bunch pressing without crushing (Chardonnay), respectively, released 39 and 18% of total phenols. For Merlot wines, MLF did not affect the extraction of total smoke-derived phenols. Conclusions: Under standardised exposure conditions (duration, intensity and phenology), the three cultivars studied accumulated a similar concentration of total phenols in grapes. The grape-processing and winemaking methods, however, can bring about a fourfold difference in the concentration of total phenols of wines. The smoke-derived phenols extracted from grapes into wine and the distribution of these phenols between the volatile and conjugated pools were not affected by MLF. Significance of the Study: The key findings reported here have the potential to improve decision-making by grapegrowers and winemakers on the effect of cultivar and winemaking practice on potential smoke taint in wine.

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Section: Fuel Types and Fuel Compilationmentioning

confidence: 99%

Winemaking practice affects the extraction of smoke‐borne phenols from grapes into wines

Kelly

Zerihun

Hayasaka

et al. 2014

Australian Journal of Grape and Wine Research

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“…Sheppard et al (2009) reported that methoxyphenols (including guaiacol and 4-MG) arise from the partial pyrolysis of lignin and are key contributors to the aroma of wood smoke. This is supported by Kelly et al (2012), who also found that, regardless of vegetation fuel type, the compounds guaiacol and 4-MG represented roughly 20% of the total phenols found in smoke-tainted wines.…”

Section: Introductionmentioning

confidence: 55%

“…Experimental error during smoke treatments may also have had a role to play. During smoke treatments of the individual field repeats, the density of the smoke was not measured as in the study by Kelly et al (2012), who used a laser nephelometer to regulate smoke density during the treatments. In the current study, smoke density was evaluated subjectively.…”

Section: Impact Of Smoke Exposure On Sensory Properties Of Red Winementioning

confidence: 99%

“…Bushfires are seldom hot enough or supplied with enough oxygen for complete combustion of plant biomass to occur. Low molecular mass and highly volatile compounds, including phenols, are formed under flaming conditions (Kelly et al, 2012). While vegetation fires are not unique to South Africa, the flora found in the Western Cape is different from that in any other region in which grapevines are grown, as fynbos plantations are often adjacent to vineyards (Cowling et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Guaiacol and 4-methylguaiacol (4-MG) have been used as key indicators of smoke exposure and potential taint formation (Kennison et al, 2007;Sheppard et al, 2009). More recently, studies have demonstrated that additional volatile phenolic compounds (cresols, phenols and syringols) may account for taint characteristics in smokeaffected wines (Kelly et al, 2012;2014;Parker et al, 2012). Sheppard et al (2009) reported that methoxyphenols (including guaiacol and 4-MG) arise from the partial pyrolysis of lignin and are key contributors to the aroma of wood smoke.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Impact of Smoke From Vegetation Fires on Sensory Characteristics of Cabernet Sauvignon Wines Made From Affected Grapes

Vries¹,

Buica²,

Brand³

et al. 2016

SAJEV

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The increased incidence of vegetation fires near vineyards in the Western Cape, South Africa has led to growing concern over smoke taint in wine made from affected grapes. This study focused on the sensory properties of wines made from grapes that have been exposed to bushfire smoke. Cabernet Sauvignon grapes (ten days' post-véraison) were exposed to a single, hour-long treatment with smoke from burning fynbos under controlled conditions. The grapes were allowed to ripen and wines were then produced. Descriptive analysis of the wines was done for aroma and taste attributes. The results of the investigation show that the exposure of grapes to smoke during ripening led to sensory differences between wines made from different treatments, and that wines made from smoke-exposed grapes were perceived as having 'burnt', 'smoky' aromas and an 'ashy' aftertaste. Despite levels of free volatile phenols (VPs) being below or close to odour threshold levels for individual phenols, their combination led to a perception of the socalled 'burnt rubber' taint perceived in some South African red wines.

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Smoke from simulated forest fire alters secondary metabolites in Vitis vinifera L. berries and wine

Noestheden

Noyovitz

Riordan-Short

et al. 2018

Planta

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The exposure of Vitis vinifera L. berries to forest fire smoke changes the concentration of phenylpropanoid metabolites in berries and the resulting wine. The exposure of Vitis vinifera L. berries (i.e., wine grapes) to forest fire smoke can lead to a wine defect known as smoke taint that is characterized by unpleasant "smoky" and "ashy" aromas and flavors. The intensity of smoke taint is associated with the concentration of organoleptic volatile phenols that are produced during the combustion-mediated oxidation of lignocellulosic biomass and subsequently concentrated in berries prior to fermentation. However, these same smoke-derived volatile phenols are also produced via metabolic pathways endogenous to berries. It follows then that an influx of exogenous volatile phenols (i.e., from forest fire smoke) could alter endogenous metabolism associated with volatile phenol synthesis, which occurs via the shikimic acid/phenylpropanoid pathways. The presence of ozone and karrikins in forest fire smoke, as well as changes to stomatal conductance that can occur from exposure to forest fire smoke also have the potential to influence phenylpropanoid metabolism. This study demonstrated changes in phenylpropanoid metabolites in Pinot noir berries and wine from three vineyards following the exposure of Vitis vinifera L. vines to simulated forest fire smoke. This included changes to metabolites associated with mouth feel and color in wine, both of which are important sensorial qualities to wine producers and consumers. The results reported are critical to understanding the chemical changes associated with smoke taint beyond volatile phenols, which in turn, may aid the development of preventative and remedial strategies.

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Exposure of grapes to smoke of vegetation with varying lignin composition and accretion of lignin derived putative smoke taint compounds in wine

Cited by 30 publications

References 39 publications

Winemaking practice affects the extraction of smoke‐borne phenols from grapes into wines

Winemaking practice affects the extraction of smoke‐borne phenols from grapes into wines

The Impact of Smoke From Vegetation Fires on Sensory Characteristics of Cabernet Sauvignon Wines Made From Affected Grapes

Smoke from simulated forest fire alters secondary metabolites in Vitis vinifera L. berries and wine

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