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WSU’s Voice of the Vine – Grape Flour, Innovators, New VEEN – April 25, 2013

Posted by | April 25, 2013

Good to The Last Drop: From Wine Grapes to Granola Bars

Gena McKahan presents her research poster about granola bars made with grape-seed flour.
Gena McKahan presents her research poster about granola bars made with grape-seed flour.

The remains of wine grapes picked and pressed typically return to fields as fertilizers, but scientists are also finding ways to recycle those edible remains into healthy foods.

Take Gena McKahan’s gluten-free, merlot grape-seed flour granola bar, for example. As a food science undergraduate at Washington State University, McKahan was curious how different amounts of merlot grape-seed flour would change a granola bar’s antioxidant content when baked with other ingredients. About half the antioxidants in grapes are found in the pomace—the pulpy pile of skins, seeds, and stems leftover from winemaking—and have been shown to help prevent some cancers and cardiovascular diseases.

McKahan made granola bars using a variety of percentages of grape-pomace flour and, overall, her data analysis showed an increase in antioxidant content as the amount of grape-seed flour increased.

“I worked in health care for seven years as an ER tech, so I have seen a lot of people with diabetes and Celiac disease,” McKahan said. She believes developing functional foods (foods with added nutritional value) can help an increasingly gluten-sensitive and diabetic population more easily and accessibly meet their dietary needs.

“Gluten-free products and antioxidants are also part of the health trend,” McKahan said. “The population is looking at labels.”

AprésVin flour made from merlot grape seeds.
AprésVin flour made from merlot grape seeds.

Even if a granola or snack bar is nutritious, whether or not consumers will eat it depends largely on taste—an especially pertinent concern since wine flours tend to be more astringent, or bitter, McKahan said. In addition to grape-seed flour, the granola bar included buckwheat, rice, teff seed, and potato starch flavor. Overall, a consumer panel of 60 people said they preferred the granola bars containing 0 and 5% grape pomace flour in comparison to bars with 10 and 15%.

The research also confirms WSU sensory analyst Carolyn Ross and researcher Maria Rosales’ previous study, published in the Journal of Sensory Sciences, which suggested a granola bar with less grape-seed flour still had higher than zero antioxidant content and could be marketable. In their recipe, Ross and Rosales included sunflower seeds, another rich source of antioxidants. McKahan omitted sunflower seeds in her analysis confirming grape-seed flour on its own provides a supply of antioxidants when baked.

Eric Leber, co-owner and president of AprèsVin (French for “After Wine”) donated merlot flour for the experiments. He’s an advocate of using the whole grape. After a winemaker is done with the grapes, the seeds can be pressed for oil and then ground into flour. Leber expresses gratitude for the partnership with WSU researchers and says those in the grape-seed flour industry can use the information to inform their customers about how to best use the flours when baking.

“Using grape pomace is all about sustainability which is important in developing a viable wine industry from both a business and environmental standpoint,” he said. “It’s just a win-win-win.”

And with 8 million tons of grape pomace produced annually worldwide, there’s plenty of research material to go around.

Learn more about research in the School of Food Science at

-Rachel Webber

What’s Science Got to Do with the Wine in Your Glass?

Thomas Henick-Kling talks about the importance of science in the growing and making of a great glass of wine.
Thomas Henick-Kling talks about the importance of science in the growing and making of a great glass of wine.

In a single glass of wine you may discover hints of peach, citrus, mineral, melon, smoke, or spice. But you may not notice that the same glass holds a complex blend of geology, biology, chemistry, microbiology, and meteorology, with a touch of technology. Thomas Henick-Kling, director of the WSU Viticulture and Enology Program, told over 120 wine enthusiasts about the science embodied in glass of wine, at the April WSU Innovators Lecture in Seattle.

Henick-Kling described the skyrocketing growth of Washington’s wine industry in the last two decades and the pivotal role that science plays in the success of this $8.6 billion industry. Washington is now the second largest producer of premium wines in the United States. He touched on a broad array of research projects conducted at WSU, all of which contribute to wines that display regional and grape varietal flavors.

Wine Science Begins with the Landscape

Each of Washington’s 13 distinct viticultural areas (AVAs) produces wines that express the unique terroir of the area. Terroir is the complex and synergistic effect of soil, climate, and topography, as well as grape cultivars and vineyard management style on a wine. Basalt bedrock, Missoula-flood sand and gravel, wind-deposited loess – all contribute to the individuality of grapes grown in regions such as Red Mountain, Ancient Lakes, or Horse Heaven Hills. To the trained palette, the flavors and results of terroir are apparent.

Climate conditions vary throughout the wine growing regions of Washington and are monitored closely by the WSU AgWeatherNet system. With 144 weather stations located throughout the state, AgWeatherNet provides vineyard managers with region-specific information that helps them know when to turn on wind machines to protect buds during cold snaps and when to best employ disease and pest interventions.

Researchers at WSU are modeling grapevine development to understand the relationship of irrigation timing and water quantity and their effects on grape flavors and cold hardiness. They’re developing sensor-based decision tools for precision canopy and water management. Plant pathologists are learning how plants infected with leafroll virus produce less ripe fruit, which affects wine quality. They’re discovering how restoring native habitat supports biological pest controls in vineyards.

Beyond the Vineyard

Wine science and the quest for regional flavor extend well beyond the vineyard. “I’ve never found wine in the vineyard,” said Henick-Kling. “Wine flavor begins with the grape and is modified by the microorganisms that are allowed to prosper during fermentation.” Henick-Kling, a microbiologist and fermentation specialist, explores the multiple personalities of these microbes. “Each yeast strain has its own character that lends to the taste of wine. Only about 100 strains have been explored for their unique qualities so far. We’re characterizing new strains to identify undiscovered flavors and aromas,” he said.

Enologists are exploring the detailed chemistry of compounds that impart specific flavors, aromas, color, and texture; how they’re affected by heat; and how they can be extracted during winemaking. Sensory and consumer scientists are conducting sensory evaluations and using analytical chemistry techniques to identify and describe wine flavors and aromas to better understand precisely what consumers mean when they say, “I like this wine.”

World-Class Wine Science Center

In the vineyard, the winery, and the lab, wine science must be tied to the local conditions that impart the unique characteristics of a wine. Ted Baseler, CEO of Ste. Michelle Wine Estates and WSU Regent, spoke about the campaign to build a new WSU Wine Science Center to be located at WSU Tri-Cities – in the heart of Washington’s wine country.

“With $17.5 million raised by industry, private, and public donors, we’re just $4.5 million from establishing a world-class research and teaching center that is a steeple of excellence,” Baseler said. Ste. Michelle recently hired two graduates from the WSU Viticulture and Enology Program. “They were turnkey — they knew exactly what to do. WSU is producing scientifically well-trained candidates for employment in the industry.”

WSU offers the only Bachelor’s program in wine science in Pacific Northwest, in addition to graduate studies and certificate programs.

Learn more about wine science research and educational opportunities by visiting

-Sylvia Kantor

Spring issue of Viticulture and Enology Extension News now available

VEENThe new issue of VEEN is ready for you to download. This issue has articles about using native plants for biocontrol, understanding the biophysics of water and its relationship to grape fruit quality, a new graft-transmissible grape disease, the new electronic “tongue” in the WSU wine sensory lab, and a winemaking article on tannin extraction and astringency.

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