The effects of shading on monoterpene accumulation in ‘Traiminette’ grape berries and the identification and quantitative analysis of monoterpene consitituents
Abstract
Traminette is a French-American hybrid wine grape variety produced from a cross of JS 23.416 x Gewürztraminer. It has become of increasing interest in vineyards and wineries throughout the Midwest and East due to its cold hardiness and potential to produce quality white wines of aromatic character. Monoterpenes are the major odor impact aroma compounds found in this variety, and monoterpene production in berries is significantly influenced by solar radiation and shading. Berries from fully exposed cluster contain 22% greater levels of monoterpene glycosides than heavily shaded berries under >3 leaf layers of canopy. Wines from various training systems have different volatile and sensory profiles despite similar levels of monoterpenes at harvest, suggesting some dynamic change in monoterpene profile with differences in cluster zone shading. Wines are dominated by floral, spice, apricot and citrus aromas, which are related to their monoterpene constituents. Cis-rose oxide has been found as the most odor active aroma compound in Traminette among 17 monoterpenes and 4 norisoprenoids that were found in all samples. Comparative studies of Traminette and Gewürztraminer indicate nearly complete matches of the monoterpene constituents and proportions. Traminette contained double the monoterpene concentrations (6-7 mg L-1) of Gewürztraminer, indicating the great aromatic potential of this variety.
Degree
Ph.D.
Advisors
Bordelon, Purdue University.
Subject Area
Horticulture|Agricultural chemicals|Botany
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