scholarly journals Glycosylation of Volatile Phenols in Grapes Following Pre-Harvest (On-Vine) vs. Post-Harvest (Off-Vine) Exposure to Smoke

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5277
Author(s):  
Julie A. Culbert ◽  
WenWen Jiang ◽  
Renata Ristic ◽  
Carolyn J. Puglisi ◽  
Elizabeth C. Nixon ◽  
...  
Keyword(s):  
Sensory Analysis ◽  
Field Trials ◽  
Smoke Exposure ◽  
Cabernet Sauvignon ◽  
Financial Viability ◽  
Volatile Phenols ◽  
Post Harvest ◽  
Volatile Phenol ◽  
Phenol Glycosides

Taint in grapes and wine following vineyard exposure to bushfire smoke continues to challenge the financial viability of grape and wine producers worldwide. In response, researchers are studying the chemical, sensory and physiological consequences of grapevine smoke exposure. However, studies involving winemaking trials are often limited by the availability of suitable quantities of smoke-affected grapes, either from vineyards exposed to smoke or from field trials involving the application of smoke to grapevines. This study compared the accumulation of volatile phenol glycosides (as compositional markers of smoke taint) in Viognier and Cabernet Sauvignon grapes exposed to smoke pre- vs. post-harvest, and found post-harvest smoke exposure of fruit gave similar levels of volatile phenol glycosides to fruit exposed to smoke pre-harvest. Furthermore, wines made from smoke-affected fruit contained similar levels of smoke-derived volatile phenols and their glycosides, irrespective of whether smoke exposure occurred pre- vs. post-harvest. Post-harvest smoke exposure therefore provides a valid approach to generating smoke-affected grapes in the quantities needed for winemaking trials and/or trials that employ both chemical and sensory analysis of wine.

scholarly journals Uptake and Glycosylation of Smoke-Derived Volatile Phenols by Cabernet Sauvignon Grapes and Their Subsequent Fate during Winemaking

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3720 ◽  
Author(s):  
Colleen Szeto ◽  
Renata Ristic ◽  
Dimitra Capone ◽  
Carolyn Puglisi ◽  
Vinay Pagay ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Compositional Analysis ◽  
Sprinkler System ◽  
Smoke Exposure ◽  
Cabernet Sauvignon ◽  
Significant Delay ◽  
Volatile Phenols ◽  
Volatile Phenol ◽  
Marker Compounds ◽  
Glycosylation Pathway

Wine made from grapes exposed to bushfire smoke can exhibit unpleasant smoky, ashy characters, which have been attributed to the presence of smoke-derived volatile phenols, in free or glycosylated forms. Here we report the uptake and glycosylation of volatile phenols by grapes following exposure of Cabernet Sauvignon vines to smoke, and their fate during winemaking. A significant delay was observed in the conversion of volatile phenols to their corresponding glycoconjugates, which suggests sequestration, the presence of intermediates within the glycosylation pathway and/or other volatile phenol storage forms. This finding has implications for industry in terms of detecting smoke-affected grapes following vineyard smoke exposure. The potential for an in-canopy sprinkler system to mitigate the uptake of smoke-derived volatile phenols by grapes, by spraying grapevines with water during smoke exposure, was also evaluated. While “misting” appeared to partially mitigate the uptake of volatile phenols by grapes during grapevine exposure to smoke, it did not readily influence the concentration of volatile phenols or the sensory perception of smoke taint in wine. Commercial sensors were used to monitor the concentration of smoke particulate matter (PM) during grapevine exposure to low and high density smoke. Similar PM profiles were observed, irrespective of smoke density, such that PM concentrations did not reflect the extent of smoke exposure by grapes or risk of taint in wine. The sensors could nevertheless be used to monitor the presence of smoke in vineyards during bushfires, and hence, the need for compositional analysis of grapes to quantify smoke taint marker compounds.

scholarly journals Potential Mitigation of Smoke Taint in Wines by Post-Harvest Ozone Treatment of Grapes

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1798
Author(s):  
Margherita Modesti ◽  
Colleen Szeto ◽  
Renata Ristic ◽  
WenWen Jiang ◽  
Julie Culbert ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Sensory Perception ◽  
Smoke Exposure ◽  
Ozone Treatment ◽  
Volatile Phenols ◽  
Post Harvest ◽  
Gaseous Ozone ◽  
Volatile Phenol ◽  
Marker Compounds ◽  
Phenol Glycoside

When bushfires occur near grape growing regions, vineyards can be exposed to smoke, and depending on the timing and duration of grapevine smoke exposure, fruit can become tainted. Smoke-derived volatile compounds, including volatile phenols, can impart unpleasant smoky, ashy characters to wines made from smoke-affected grapes, leading to substantial revenue losses where wines are perceivably tainted. This study investigated the potential for post-harvest ozone treatment of smoke-affected grapes to mitigate the intensity of smoke taint in wine. Merlot grapevines were exposed to smoke at ~7 days post-veraison and at harvest grapes were treated with 1 or 3 ppm of gaseous ozone (for 24 or 12 h, respectively), prior to winemaking. The concentrations of smoke taint marker compounds (i.e., free and glycosylated volatile phenols) were measured in grapes and wines to determine to what extent ozonation could mitigate the effects of grapevine exposure to smoke. The 24 h 1 ppm ozone treatment not only gave significantly lower volatile phenol and volatile phenol glycoside concentrations but also diminished the sensory perception of smoke taint in wine. Post-harvest smoke and ozone treatment of grapes suggests that ozone works more effectively when smoke-derived volatile phenols are in their free (aglycone) form, rather than glycosylated forms. Nevertheless, the collective results demonstrate the efficacy of post-harvest ozone treatment as a strategy for mitigation of smoke taint in wine.

scholarly journals Amelioration of Smoke Taint in Cabernet Sauvignon Wine via Post-Harvest Ozonation of Grapes

Beverages ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 44
Author(s):  
Margherita Modesti ◽  
Colleen Szeto ◽  
Renata Ristic ◽  
WenWen Jiang ◽  
Julie Culbert ◽  
...  
Keyword(s):  
Sensory Attributes ◽  
Sensory Properties ◽  
Ozone Treatment ◽  
Cabernet Sauvignon ◽  
Negative Effects ◽  
Volatile Phenols ◽  
Post Harvest ◽  
Perceived Intensity ◽  
Wine Composition ◽  
Marker Compounds

Strategies that mitigate the negative effects of vineyard exposure to smoke on wine composition and sensory properties are needed to address the recurring incidence of bushfires in or near wine regions. Recent research demonstrated the potential for post-harvest ozonation of moderately smoke-exposed grapes to reduce both the concentration of smoke taint marker compounds (i.e., volatile phenols and their glycosides) and the perceived intensity of smoke taint in wine, depending on the dose and duration of ozone treatment. The current study further evaluated the efficacy of ozonation as a method for the amelioration of smoke taint in wine by comparing the chemical and sensory consequences of post-harvest ozonation (at 1 ppm for 24 h) of Cabernet Sauvignon grapes following grapevine exposure to dense smoke, i.e., ozone treatment of more heavily tainted grapes. Ozonation again yielded significant reductions in the concentration of free and glycosylated volatile phenols—up to 25% and 30%, respectively. However, although the intensities of smoke-related sensory attributes were generally lower in wines made with smoke-exposed grapes that were ozonated (compared to wines made with smoke-exposed grapes that were not ozonated), the results were not statistically significant. This suggests that the efficacy of ozone treatment depends on the extent to which grapes have been tainted by smoke.

scholarly journals Assessment of Smoke Contamination in Grapevine Berries and Taint in Wines Due to Bushfires Using a Low-Cost E-Nose and an Artificial Intelligence Approach

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5108 ◽  
Author(s):  
Sigfredo Fuentes ◽  
Vasiliki Summerson ◽  
Claudia Gonzalez Viejo ◽  
Eden Tongson ◽  
Nir Lipovetzky ◽  
...  
Keyword(s):  
Low Cost ◽  
Field Trials ◽  
Smoke Exposure ◽  
High Density ◽  
Machine Learning Algorithms ◽  
Classification Model ◽  
Test Model ◽  
Volatile Phenols ◽  
Experimental Treatments ◽  
Harvest Model

Bushfires are increasing in number and intensity due to climate change. A newly developed low-cost electronic nose (e-nose) was tested on wines made from grapevines exposed to smoke in field trials. E-nose readings were obtained from wines from five experimental treatments: (i) low-density smoke exposure (LS), (ii) high-density smoke exposure (HS), (iii) high-density smoke exposure with in-canopy misting (HSM), and two controls: (iv) control (C; no smoke treatment) and (v) control with in-canopy misting (CM; no smoke treatment). These e-nose readings were used as inputs for machine learning algorithms to obtain a classification model, with treatments as targets and seven neurons, with 97% accuracy in the classification of 300 samples into treatments as targets (Model 1). Models 2 to 4 used 10 neurons, with 20 glycoconjugates and 10 volatile phenols as targets, measured: in berries one hour after smoke (Model 2; R = 0.98; R2 = 0.95; b = 0.97); in berries at harvest (Model 3; R = 0.99; R2 = 0.97; b = 0.96); in wines (Model 4; R = 0.99; R2 = 0.98; b = 0.98). Model 5 was based on the intensity of 12 wine descriptors determined via a consumer sensory test (Model 5; R = 0.98; R2 = 0.96; b = 0.97). These models could be used by winemakers to assess near real-time smoke contamination levels and to implement amelioration strategies to minimize smoke taint in wines following bushfires.

scholarly journals Incidence of volatile phenols in Montenegrin red wines: Vranac, Kratosija and Cabernet sauvignon

2020 ◽  
pp. 10-10
Author(s):  
Sanja Radonjic ◽  
Helena Prosen ◽  
Vesna Maras ◽  
Lea Demsar ◽  
Tatjana Kosmerl
Keyword(s):  
Cabernet Sauvignon ◽  
Red Wines ◽  
Grape Variety ◽  
Chemical Parameters ◽  
Alcohol Content ◽  
Volatile Phenols ◽  
Oak Chips ◽  
Volatile Phenol ◽  
Bottle Aging ◽  
The Impact

The main objective of this study was to determine the impact of three different commercial yeasts and two lactic acid bacteria, as well as the use of oak (chips and staves) on the volatile phenol (VP) formation in Montenegrin aged red wines (Vranac, Kratosija and Cabernet Sauvignon) of the 2013 vintage. Standard chemical parameters of the wines were determined in order to establish relationship with VP. After three years of bottle aging, chemical parameters of wines (alcohol content, residual sugars (RS), pH, free and total SO2, anthocyanins) and VP (4-ethylphenol and 4-ethylguaiacol) were determined. Volatile phenols were found in 18 samples of Kratosija and 5 samples of Vranac. Volatile phenols were not detected in Cabernet Sauvignon wines. Kratosija as a grape variety from the Montenegrin terroir during 2013 vintage had the highest potential for the VP formation, while the highest content of 4-ethylphenol (2.84 mg/L) and 4-ethylguaiacol (0.52 mg/L) was determined in Vranac wine. It was demonstrated that VP would be formed in wines even with high alcohol content (>12.50 v/v %), low pH (<3.30) and with free SO2 concentrations at bottling of 30-35 mg/L.

Changes in Smoke-Taint Volatile-Phenol Glycosides in Wildfire Smoke-Exposed Cabernet Sauvignon Grapes throughout Winemaking

2019 ◽  
Vol 70 (4) ◽  
pp. 373-381 ◽  
Author(s):  
Andrew Caffrey ◽  
Larry Lerno ◽  
Arran Rumbaugh ◽  
Raul Girardello ◽  
Jerry Zweigenbaum ◽  
...  
Keyword(s):  
Cabernet Sauvignon ◽  
Wildfire Smoke ◽  
Volatile Phenol ◽  
Phenol Glycosides

Infrared spectroscopy coupled with chemometrics in coffee post-harvest processes as complement to the sensory analysis

LWT ◽  
2021 ◽  
pp. 111304
Author(s):  
Yeison Fernando Barrios-Rodríguez ◽  
Cristhian Andrés Rojas Reyes ◽  
Joan Sebastián Triana Campos ◽  
Joel Girón-Hernández ◽  
Juan Rodríguez-Gamir
Keyword(s):  
Infrared Spectroscopy ◽  
Sensory Analysis ◽  
Post Harvest

scholarly journals Removal of Volatile Phenols From Wine Using Crosslinked Cyclodextrin Polymers

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 910 ◽  
Author(s):  
Chao Dang ◽  
Vladimir Jiranek ◽  
Dennis K. Taylor ◽  
Kerry L. Wilkinson
Keyword(s):  
Solid Phase ◽  
Crosslinking Agent ◽  
Wine Industry ◽  
Hexamethylene Diisocyanate ◽  
Gas Chromatography Mass Spectrometry ◽  
Batch Adsorption ◽  
Volatile Phenols ◽  
Phenol Adsorption ◽  
Volatile Phenol ◽  
Langmuir And Freundlich Models

Volatile phenols have been implicated as contributors to off-odors associated with taints from bushfire smoke and microbial spoilage. Various methods for the amelioration of off-odors have been evaluated, but to date, they have not included cyclodextrin (CD) polymers. In the current study, two CD polymers were prepared from β- and γ-CD, using hexamethylene diisocyanate (HDI) as a crosslinking agent. Adsorption tests were performed with four volatile phenols (guaiacol, 4-methylguaiacol, 4-ethylguaiacol and 4-ethylphenol) at concentrations up to 1 mg/L. The removal of volatile phenols by CD polymers achieved equilibrium almost instantly, with isotherm tests suggesting an adsorption capacity of 20.7 µg of volatile phenol per gram of polymer. Langmuir and Freundlich models were subsequently used to fit the data. In batch adsorption tests, the CD polymers achieved 45 to 77% removal of volatile phenols. Polymer reusability was also evaluated and was found to be excellent. A comparison between volatile phenol adsorption by CDs vs. CD polymers, determined using a novel four-phase headspace solid-phase microextraction (HS-SPME) method for gas chromatography-mass spectrometry (GC-MS), suggests CD polymers offer several advantages for use by the wine industry.

scholarly journals Pyrazine contents in four red grape varietes cultivated in warm climate

OENO One ◽  
2006 ◽  
Vol 40 (4) ◽  
pp. 203
Author(s):  
Raquel Romero ◽  
Juan Luis Chacón ◽  
Esteban García ◽  
Jesús Martínez
Keyword(s):  
Sensory Analysis ◽  
Cabernet Sauvignon ◽  
Warm Climate ◽  
Perception Threshold ◽  
Green Pepper ◽  
La Mancha ◽  
Red Grape ◽  
Grape Varieties

<p style="text-align: justify;">We analysed 2-methoxy-3-ethylpyrazine and 2-methoxy-3-isobutylpyrazine content in 4 grape varieties cultivated in Castilla-La Mancha. A sensory analysis of the wines obtained from these grapes was also performed. The results revealed the presence of the two methoxypyrazines studied in all four varieties, in concentrations lower than those published for these varieties in regions with cooler climates. Significant differences were observed in 2-methoxy-3-isobutylpyrazine content between the different varieties: Cabernet-Sauvignon&gt;Merlot&gt;Syrah&gt;Cencibel. The correlation between 2- methoxy-3-isobutylpyrazine content and the « green pepper » descriptor suggests a perception threshold at 3 ng/L in young wines.</p>

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