How to extract more antioxidants from wine ‘leftovers’

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. (Credit: Julia Frost/Flickr)

The leftovers from making wine usually end up in a landfill, but scientists say it might be possible to use enzymes to turn that waste into natural food additives or supplements.

Researchers ground muscadine skin or seeds to a powder and extracted phenolics by soaking the powder in a solution of enzymes, explains Maurice Marshall, professor of food science and human nutrition at University of Florida.

Marshall and colleagues suspected the process would make it easier to extract phenolic compounds, which are considered to have health benefits.

To their surprise, the enzymes actually decreased the phenolics from the discarded material, but the enzyme hydrolysis—a form of digestion—released more antioxidants, Marshall says.

“You got less phenolics, but you improve their antioxidant activity.”

Natural vs. synthetic

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.

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

Currently, the food industry puts synthetic antioxidants into food to preserve it. Synthetic antioxidants also preserve fats and oils in cosmetics and pharmaceuticals.

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

“This concept of using natural antioxidants in many different things in the food world is a nice concept to consumers,” he says.

The study is published online in the journal Food Chemistry and is scheduled to appear in the print edition in August.

Source: University of Florida