Researcher: Pomace full of promise

CORVALLIS, Ore. — It’s hard to imagine a rigid 4-by-4-inch tile that smells like a Fruit Roll-Up as the next big thing in viticulture, but an Oregon State University researcher says it could be.

Yanyun Zhao, a value-added food products specialist with the OSU Extension Service, has recently developed new uses for grape pomace — the skins, pulp, seeds and stems. The U.S. wine industry produces 4 million tons of wine grape waste each year.

Her research has focused on developing an array of technology that uses waste and increases the value of crops like grapes, pears and cranberries grown in the state.

“For me, it’s about helping the industry and people to find more value-added applications and researching discoveries — especially helping Oregon industry,” she said.

That possibility has gotten the attention of the wine industry.

“To the extent that wineries have excess pomace and the ability to sell or convert it to profitable products, there would seem to be a place for pomace products,” Nancy Light, Wine Institute vice president of communications, said in an email.

Zhao said the scented board-like tiles, which can be formed into biodegradable products like plant pots, are just one potential use for pomace.

Grape growers could also benefit by drying pomace on-site and grinding it into a powder that could be used to enhance yogurt or salad dressing.

“Why add it to yogurt?” Zhao asked. “Yogurt doesn’t have dietary fiber, but it has milk, meaning it has some sugar and the pomace can protect that from breaking down.”

Another possible use for pomace is using it as a food additive, she said.

It is high in polyphenols, known in food and medical industries as antioxidants, which act as a preserving agent by reducing cell damage that occurs when oxygen reacts with compounds like lactose, Zhao said.

For consumers, antioxidants can mean better health.

Still another option for the pomace is crushing it into a powder and using it as a gluten-free flour substitute in bread and muffin recipes.

Zhao has also discovered that before processing, cellulose and pectin can be extracted from pomace. Adding them to a specialized binding chemical can create an edible film coating chock full of antioxidants, natural fruit flavor and color that preserves food longer. The coating has a texture similar to rice paper, Zhao said.

She said white wine pomace, which is typically not fermented, is a better suited to be processed as a food additive because the only flavor it gives off is a hint of sweetness from the fruit. Red wine pomace, Zhao said, is preferred for making the non-consumable products like boards because it bears a strong fermented flavor.

Zhao is not new to innovation. In 2004, she co-patented a “super-packaging” material made from a egg white lysozyme protein and crab shell chitosan fiber combination. Like the pomace film, which is high in antioxidants, this biofilm has antimicrobial traits that preserve food, thus adding value.

She is currently seeking industry partners to further develop the grape and other fruit pomace technology.

Zhao took an unusual road to OSU.

In 1991, with a bachelor’s degree in cryogenic engineering and a master’s degree in heat transfer from the University of Shanghai for Science and Technology, Zhao left China and settled at Louisiana State University. She completed her Ph.D. in food engineering in 1993. In 2001, she and her husband moved to Corvallis, Ore.

“I consider myself 100 percent Oregonian,” she said.

Yanyun Zhao

Age: 51

Hometown: Yangzhou, China

Family: Husband, 1 son

Education: B.S. and M.S., University of Shanghai for Science and Technology; Ph.D., Louisiana State University, food engineering

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