Thesis
Influence of Brettanomyces volatile compounds on the sensory properties of red wine
Washington State University
Master of Science (MS), Washington State University
2017
Handle:
https://hdl.handle.net/2376/102800
Abstract
The presence and further occurrence of wine spoilage due to the yeast Brettanomyces bruxellensis is of great concern to the wine industry. Several compounds influence the sensory impact spoiled by the yeast including 4-ethylphenol (4-EP), 4-ethylguaiacol (4-EG), 4- ethylcatechol (4-EC), and isovaleric acid (IA). The objective of this study was to investigate the influence of metabolites of Brettanomyces on red wine aroma, flavor, and finish using sensory analysis. Results from consumer evaluations (n=121) conducted in the United States and Portugal demonstrated consumers' ability to detect differences in red wine aroma due to 4-EP, 4- EG, and 4-EC. Among the five spiked samples, with increasing levels of 4-EP, 4-EG, and 4-EC, the greatest degree of difference was found between the two treatment levels corresponding to reported detection and recognition threshold ranges of 4-EP and 4-EG. Additionally, results provided useful context on how wine knowledge and cultural variations may affect the detection of metabolites of Brettanomyces. For Portuguese consumers, the medium and high knowledge levels had significantly higher difference from control values for two treatments. To examine the influence of wine matrix on the perception of the temporal properties of red wines, Temporal Check-All-That-Apply (TCATA) was used to evaluate wine finish of two flavor matrices containing low and high concentrations of 4-EP, 4-EG, and IA. Following a familiarization session, consumers (n=105) evaluated seven wine samples for changes in temporal perceptions using TCATA. Results indicated wine finish duration was influenced by metabolites of Brettanomyces (p< 0.05). In addition, the presence of oak more strongly masked the perception of 4-EP, 4-EG, and IA aromas and flavors in a red wine compared to a green wine composition. In examining liking of the wine samples, three clusters of consumers were identified; Cluster 1 disliked all samples containing metabolites of Brettanomyces, Cluster 2 liked all samples, and Cluster 3 preferred samples containing low concentrations of Brettanomyces metabolites, regardless of wine composition. Overall, this research has provided useful information regarding the perception and acceptance of several Brettanomyces metabolites on the sensory properties of red wine, and demonstrated how factors including wine knowledge provide useful context when examining wine spoilage.
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Details
- Title
- Influence of Brettanomyces volatile compounds on the sensory properties of red wine
- Creators
- Megan Rae Schumaker
- Contributors
- Carolyn Felicity Ross (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525177401842
- Language
- English
- Resource Type
- Thesis