The residue from wine grapes could be beneficial to human health, according to a new study from UC Davis. The researchers have discovered a wealth of potentially health-enhancing compounds and sugar molecules called oligosaccharides in the remains of wine grapes.
Oligosaccharides are a source of nutrition found in many plant and animal tissues, including human breast milk.
In California alone, about four million tons of wine is produced each year, which also creates thousands of tons of residue like grape skins, seeds, and pulp.
Wine grape remains, also known as marc, make up about 30 percent of the original grape material, and much of it is left behind to decompose in the sun.
The researchers analyzed the molecular composition of chardonnay residue provided by Jackson Family Wines and Sonomaceuticals.
“We were surprised by the diversity of the oligosaccharides in the chardonnay wine grapes, including the presence of structural elements found in mother’s milk,” said study lead author Amanda Sinrod.
“It’s all about sustainable wine production and finding a second life for wine grapes,” said Professor Daniela Barile. “Up to this point, chardonnay marc has been regarded as a byproduct of winemaking with little or no value. Early results are encouraging that marc could be a valuable source for oligosaccharides and other compounds that support health and nutrition.”
In previous work, UC Davis researchers helped to decode the magic of oligosaccharides in mother’s milk. The sugar molecules do not nourish the baby directly, but feed a strain of bacteria in the infant’s intestines that helps build immunity against illness and disease. The breakthrough is helping scientists develop products to improve human health.
While the current study is focused on chardonnay, Professor Barile’s team previously discovered oligosaccharides in both red and white wine residue.
“There is more research to be done, but early results are promising that chardonnay marc can become a source for developing supplements and other food products to support health,” said Professor Barile.
Oligosaccharides were found to be particularly abundant in the grape skins. The chardonnay marc samples were also rich in flavonoids, healthy compounds found in fruits and vegetables. The team is studying how growing conditions and processing may affect the health potential of viticulture waste.
“We observed significant differences in the relative abundance and type of oligosaccharides in different parts of the marc, so further research is needed to maximize their potential in food product design,” said Sinrod.
The study is published in the journal