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dc.contributor.authorKelly, Jennifer
dc.date.accessioned2019-07-29T14:00:45Z
dc.date.available2019-07-29T14:00:45Z
dc.identifier.urihttp://hdl.handle.net/10464/14396
dc.description.abstractThe appassimento process for making wine can mitigate climatic challenges associated with cool climate winemaking, as fruit is dried post-harvest, reducing vintage-to-vintage variation due to varying fruit quality. Resultant wines fermented from dried grapes are high in ethanol and described as rich and intensely flavoured. One of the quality challenges facing wine made from partially dehydrated grapes is elevated levels of undesirable oxidation compounds, such as ethyl acetate, acetic acid and acetaldehyde. In this study we aim to characterize wines made from a local yeast isolate, Saccharomyces bayanus CN1, which demonstrates limited osmotolerance and may have application to this wine style, as it is a lower producer of such compounds. Wines made with the yeast of interest were compared to wines made with the accepted commercial yeast, Saccharomyces cerevisiae, EC1118. Fermentations were established over two vintages at one and three target starting sugar concentrations and a control, respectively. Wines were chemically (enzymatic) and sensorially analyzed. Wines (year two) were subject to volatile organic compound (VOC) and volatile fatty acid (VFA) measurements via Gas Chromatography-Mass Spectrometry. Another consideration for the development of this wine style is the inclusion of Botrytis cinerea, a pathogenic fungus that commonly develops during grape drying, and may impart favourable sensorial characteristics. Grapes were dried to 28.0°Brix and were fermented with EC1118 at 0 and 10% B. cinerea infection. A consumer preference test (n=153) that measured liking of wines (CN1 and 0% and10% B. cinerea infection) was conducted. Results indicate that CN1’s upper limit for fermentation to dryness is 27.5°Brix. All CN1 wines had significantly lower concentrations (p<0.05) of oxidation compounds than the commercial yeast, and oppositely, higher glycerol levels, along with comparable ethanol concentration to EC1118 wines. Significant differences in the concentrations of VOCs and VFAs, such as 2-phenylethanol and hexanoic acid were observed both within °Brix treatments and amongst yeast strains. Sensorially, the wines differed in intensity for a number of attributes. The consumer study revealed no preference between wines vinified with the different yeast strains. This work will contribute to the optimization of this wine style in cool climate winemaking regions and beyond.en_US
dc.language.isoengen_US
dc.publisherBrock Universityen_US
dc.subjectwinemakingen_US
dc.subjectyeasten_US
dc.subjectsensory scienceen_US
dc.subjectpartially dehydrated grapesen_US
dc.subjectOntario wineen_US
dc.titleConsiderations for the Development and Optimization of Wine made from Partially Dehydrated Grapes in Ontario, Canadaen_US
dc.typeElectronic Thesis or Dissertationen_US
dc.degree.namePh.D. Biotechnologyen_US
dc.degree.levelDoctoralen_US
dc.contributor.departmentCentre for Biotechnologyen_US
dc.degree.disciplineFaculty of Mathematics and Scienceen_US
refterms.dateFOA2019-07-24T00:00:00Z


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