Date of Graduation

5-2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Food Science (PhD)

Degree Level

Graduate

Department

Food Science

Advisor

Renee T. Threlfall

Committee Member

Luke Howard

Second Committee Member

Han-Seok Seo

Third Committee Member

Andy Mauromoustakos

Fourth Committee Member

Jackson Lay, Jr.

Keywords

Aroma, Chemistry, Grapes, Wine, Winemaking

Abstract

Grapevines (Vitis spp.) are one of the most widely-planted horticultural crops, and the United States plays a major role in grape and wine production. Arkansas has a long history of grape and wine production with grapes grown in Arkansas including mostly native species, such as muscadines, and hybrids (crosses of Vitis spp.), such as Chambourcin. In addition, the University of Arkansas System Division of Agriculture (UA System) grape breeding program has cultivars and selections that have shown potential for wine production. The objectives of this research were to: evaluate effects of specific inactivated yeast application to Chambourcin grapevines on attributes of grapes and wine; determine impacts of winemaking methods on Noble muscadine wine attributes; evaluate impacts of winemaking methods on Enchantment wine attributes; and explore attributes of wines from UA System white wine genotypes (Opportunity, A-2359, and A-2574). In 2018 and 2019 at a commercial Arkansas vineyard, four rows of Chambourcin grapevines were sprayed with inactivated yeast (spray treatment) and four rows were unsprayed (control treatment). Berries were sampled from each treatment during ripening and at harvest and wines were produced from each treatment. Sprayed Chambourcin berries had higher skin elasticity, lower pH, and higher anthocyanins than control berries. Wines from sprayed grapevines had higher red color than control wines over 12-months storage, higher concentrations of fruity ester aroma compounds in analytical studies, and higher red color and better mouthfeel in sensory studies. This is the first data on inactivated yeast application to Chambourcin, but it shows potential for grapes with better winemaking attributes and wines with deeper red colors and improved sensory attributes. In 2018, Noble muscadine grapes were used to produce wines with different skin contact times and with and without the addition of a glycosidic enzyme. Noble wines with increased skin contact had higher anthocyanins and red color and spicy, dark-fruit aromas. Wines with 0-days skin contact had strawberry and candy aromas characteristic of muscadine juice. Noble wines without glycosidic enzyme had fruitier, more pleasant aromas. Therefore, skin contact time and glycosidic enzyme addition impacted the color and sensory attributes of Noble muscadine wine. Wines were produced from Enchantment grapes in 2017 and 2018 with and without the addition of tannin and oak. Enchantment wines had V. vinifera-like anthocyanins and deep red color. Enchantment wines with oak were associated with oaky, roasted, and caramelized aromas, and wines with tannin had lower overall aromas. These results suggested the potential of Enchantment grapes for producing high-quality, deeply red-colored wines with aging potential. Wines were produced from Opportunity, A-2359, and A-2574 in 2015, 2017, and 2018. The aroma/flavor of Opportunity wines was described as spicy, green apple, and peach, A-2359 wine was described as floral, grapefruit, and Muscat, and A-2574 wine was described as spicy, rose, and peach. This demonstrated that UA System white wine grapes produced wines with unique/pleasant sensory characteristics and could provide new opportunities for the Arkansas grape and wine industry. Therefore, viticultural and enological techniques enhanced the attributes of wines produced from grapes grown in Arkansas.

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