Julie Tarara, USDA-ARS
researcher based at WSU Prosser

PROSSER — For the second year in a row, WSU researchers, including Julie M. Tarara, and USDA colleagues won a Best Viticulture Paper Award from the American Society for Enology and Viticulture.

 
USDA-ARS researcher Julie M. Tarara, based at WSU’s Prosser Research and Extension Center, and her co-authors won for a paper entitled “Berry Temperature and Solar Radiation Alter Acylation, Proportion, and Concentration of Anthocyanin in Merlot Grapes.”
 
Anthocyanin is a natural phenolic compound that can be found in grapes and wine. Of all the compounds involved in creating a great bottle of wine, phenolics comprise only a small portion. Phenolics have potential human health benefits, but are essential to wine for their contributions to appearance, taste and mouthfeel. In addition, phenolics are valuable to plants: they give fruit a white to purple color, help provide protection against UV radiation, attract pollinating insects and can aid seed dispersal by herbivores.
 
Understanding how phenolics are formed under varying environmental conditions is critical to ensuring that wine grape producers are able to deliver the best possible fruit to winemakers. What Tarara and her colleagues found was that concentrations and profiles of the anthocyanin class of phenolics in grape berries appear to be determined by a combination of exposure to solar radiation and the temperature of berries as they mature.
 
Tarara and her colleagues write, “Our data indicate that temperature is a strong environmental determinant of anthocyanin profile in the berry skins, above a potentially low threshold of exposure to solar radiation.”
 
The scientists conclude that ultimately, “Manipulating vineyard conditions to alter the anthocyanin profile of the berry may become a useful approach to strategic management as we better understand the contribution of individual anthocyanins to final fruit and wine quality.”
 
In 2008, WSU horticultural scientist Markus Keller and research technology supervisor Lynn J. Mills won Best Viticulture Paper for research on pruning cold-injured Merlot vines. In 2007, Thomas Henick-Kling, the new director of WSU’s program in viticulture and enology, was a co-author of the year’s Best Enology Paper. And in 2003, WSU food scientist Sara Spayd, along with Tarara and others, authored the Best Viticulture Paper.