Vineyard Waste Being Upcycled as Antioxidant-Rich Additive

(CN) – The tale of wine spills across pages covering thousands of years in the story of humanity. Food science researchers are writing a new chapter, transforming the “waste” from humanity’s noble rot into natural antioxidants used in consumer goods.

Changmou Xu, a research assistant professor at the University of Nebraska-Lincoln, is leading a team of food scientists that want to rebrand grape waste as a renewable dietary and health resource. Over the span of 10 years, Xu has studied vineyards around the world, examining growth trends, soil fertility, and the impact of climate change on quality of wine.

In the process of winemaking, seeds, stalks and grape skins are typically discarded as waste after fermentation. These byproducts, roughly a quarter of the grape, end up in landfills. The global wine industry produces about 14 million tons of the waste – known as pomace – every year, according to the Food and Agriculture Organization of the United Nations, and winemakers struggle with what to do with it.

Pomace, can cause surface and groundwater pollution due to pesticides and fertilizers used on grapes leaching into soil. Grape waste left in landfills can contribute to the spread of diseases through flies and other pests, Xu said.

Pomace can be used as compost or fertilizer, and some winemakers have even produced a weaker, “second wine” by soaking waste grape skins in water and fermenting the mixture. Xu said the team is producing applications for pomace that can increase the economic value of the grape and wine industry while minimizing environmental contamination.

He said he understands consumers may be hesitant to use products knowing they are made with waste products from wine producers. Instead, he wants people to focus on the existing application of pomace products in health and dietary goods.

“[Our researchers] focus on the consumer demand for goods made with natural ingredients,” he said. “These pomace ingredients, as well as grape seed oil, are already in use in dietary supplements, pharmaceuticals and cosmetics.”

Grape pomace is a rich source of natural antioxidants which protect cells from free radicals, toxic byproducts of oxygen metabolism that can harm the body, Xu said.

Xu’s team is also working on applications of an antioxidant compound made from grape pomace that can extend the shelf life of common fatty foods like mayonnaise and dressing.

Using a pomace-derived antioxidant, Xu’s team reduced the chemical acrylamide, formed during high-temperature cooking, in potato chips by 60 percent. He said the compound could provide a natural alternative to EDTA, an artificial antioxidant widely added to foods, cosmetics and medicine.

“In the current consumer climate, people are looking for food labels listing natural ingredients, and grape pomace could provide one way to fulfill that need,” he said.

The group has also collaborated with biologists to determine whether the pomace compound can be effective against foodborne pathogens like E. coli and salmonella.

Xu presented his work at the 255th National Meeting & Exposition of the American Chemical Society, the world’s largest scientific society. He said he is also working on a similar study involving ginger.

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