Study shows promise for antioxidants extracted from grape seeds, skin

June 18, 2014 by Brad Buck

(Medical Xpress)—Soaking muscadine grape seeds or skins in a solution of enzymes can boost antioxidants extracted from the fruit, creating possible new uses for grape leftovers, which are loaded with nutrients, a University of Florida study shows.

After making wine, a producer typically sends the grape seeds and skins to a landfill, said Maurice Marshall, a UF/IFAS food science and human nutrition professor and study co-author. But by using cellulase, pectinase and glucosidase, scientists found the grape seeds and skin aren't just a waste product. The enzymes increase the , from the grape seeds and skins. New uses could include food additives or nutritional supplements.

Changmou Xu, a doctoral student in food science and human nutrition at UF, led the study under Marshall's advisement. Researchers ground muscadine skin or seeds to a powder and extracted phenolics by soaking the powder in a solution of enzymes, Marshall said.

Through that process, Xu and other researchers examined how enzymes break down grape seeds and skin so they could obtain phenolics and . They hoped that by treating grape skins and seeds with enzymes that break down cell walls, they could make it easier to extract phenolic compounds.

The enzymes actually decreased the phenolics from the discarded material. That was the downside, said Marshall, who's supervising Xu's doctoral work. On the upside, hydrolysis—a form of digestion—can release more antioxidants, Marshall said.

"You got less phenolics, but you improve their antioxidant activity," he said.

Muscadine grapes grow well in Florida and have thick skin that accounts for about 40 percent of the fruit's weight. The skin gives the muscadine natural resistance to disease, fungi and insects, and it stores many antioxidants, the study said.

Grape phenolics serve as anti-inflammatory agents, can reduce the risk of certain cancers and help prevent high blood pressure and heart disease, Marshall said.

Skin and seed extract from muscadine grapes can be used as a or nutritional supplement, Marshall said. Currently, the food industry puts synthetic antioxidants into food to preserve it, he said. Synthetic antioxidants also preserve fats and oils in cosmetics and pharmaceuticals.

The phenolics extracted during the UF study, on the other hand, are natural, not synthetic, antioxidants.

"This concept of using in many different things in the food world is a nice concept to consumers," he said.

In addition to Xu and Marshall, study co-authors were Yavuz Yagiz, a senior chemist in food science and human nutrition at UF; Wlodzimierz Borejsza-Wysocki, IR-4 research programs coordinator at UF; Jiang Lu, professor of viticultural sciences at Florida A&M University and Milena Ramirez-Rodrigues, a former doctoral student in and .

The study was published in the February online edition of the journal Food Chemistry and is scheduled to be in the journal's print edition in August.

Explore further: Antioxidant cookies made possible by grape seeds, study finds

Related Stories

Recommended for you

Want to exercise more? Get yourself some competition

October 27, 2016

Imagine you're a CEO trying to get your employees to exercise. Most health incentive programs have an array of tools—pamphlets, websites, pedometers, coaching, team activities, step challenges, money—but what actually ...

Sleep loss tied to changes of the gut microbiota in humans

October 25, 2016

Results from a new clinical study conducted at Uppsala University suggest that curtailing sleep alters the abundance of bacterial gut species that have previously been linked to compromised human metabolic health. The new ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.