(The Center Square) Spray coatings for grapes can block nasty flavors from wildfire smoke, according to new Oregon State University research funded by state and federal grants.
OSU researchers are working to develop a product for vineyard managers to spray on their grapes to protect them from wildfire smoke before the smoke reaches the vines, hopefully in the next several years.
“Wildfire smoke is an increasing problem for wineries in the United States and around the world, and right now vineyard managers really have no tools to manage the effects of the smoke,” Elizabeth Tomasino, an associate professor of enology at Oregon State, said. “This coating has the potential to transform the wine industry.”
Researchers embarked on this project after wildfire smoke over the Pacific Northwest in September 2020 hurt wine grape quality.
“The fires coincided with the harvest time for grapes,” a release said. “At the time, vineyard managers were unsure of the impact of wildfire smoke on their crop and, as a result, many decided the uncertainty wasn’t worth the cost to harvest their grapes and potential impact on wine quality.”
Smoke from the wildfire caused over $3 billion in losses for the wine industry.
In a paper recently published in the Journal of Agricultural and Food Chemistry, Oregon State researchers, spearheaded by Yanyun Zhao, observed three compounds called volatile phenols that contribute to smoke taint in grapes.
Zhao and Jooyeoun Jung, a senior researcher assistant professor in Zhao’s lab, worked to develop cellulose nanofiber-based coatings containing chitosan and beta-cyclodextrin that planters can safely apply to grapes in vineyards.
Chitosan is a sugar commonly found in the outer skeleton of shellfish, while beta-cyclodextrin is a substance derived from glucose. The researchers studied cellulose fiber-based coatings with different concentrations of chitosan or low methoxyl pectin, they told The Center Square in an email.
“The work showed that depending on the formulations, the films can block guaicol and syringol and capture meta-cresol, wildfire smoke compounds that when absorbed by wine grapes result in off-flavors in wine,” the researchers said.
Coating development is a challenge since the phenols which cause the nasty flavors have different chemical shapes. This makes it difficult to make a coating that properly adheres to all the shapes to block smoke.
Two years of coating application studies in the vineyard at Oregon State’s Southern Oregon Research and Extension Center in Central Point, Oregon, concluded that these coatings have no impact on the growth and quality of grapes.
Researchers also applied the coatings at Oregon State University’s Woodhall Vineyard outside Monroe, Oregon. They placed smoke chambers over the vines to test how well the coatings block smoke.
“Growers want something they can spray on their vines to protect them,” Alexander Levin, a viticulturist who serves as the director of the Southern Oregon Research and Extension Center, said . “If this becomes a commercially available thing, it’s going to be a big game-changer.”
The researchers received a $167,000 Oregon Department of Agriculture specialty block grant and a portion of its $7.65 million USDA specialty crop grant, the researchers told The Center Square.