Oligosaccharides and flavonoids identified in upcycled wine-grape pomace

26 Apr 2021 --- Grape byproducts from California’s chardonnay wine industry contain oligosaccharides and other potentially health-enhancing compounds, according to a new study from the University of California, Davis.

“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,” says Amanda Sinrod, lead author and a master’s candidate.

“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,” adds Daniela Barile, a professor working with Sinrod.

The chardonnay marc samples were also rich in flavonoids, healthy compounds found in many fruits and vegetables.

Researchers are exploring whether the oligosaccharides work independently or synergistically with these bioactive compounds to support intestinal health. The team is studying how growing conditions, vintages and processing might affect the health potential of viticulture waste.California’s wine industry produces thousands of tons of residue like grape skins, seeds, stems and pulp.

A sustainable source
The investigation, now published in LWT – Food Science and Technology, analyzed wine-grape pomace, or marc. It comprises about 30 percent of the original wine-grape material, and much of it is left to decompose in the sun.

“Up to this point, chardonnay marc has been regarded as a byproduct of winemaking with little or no value,” explains Barile.

“It’s all about sustainable wine production and finding a second life for wine grapes,” she adds.

With California producing nearly 4 million tons of wine each year, there are thousands of tons of residue like grape skins, seeds, stems and pulp that are traditionally discounted as waste.

Fighting food waste, upcycling or upgrading byproducts is a hot topic in industry at the moment, as consumers look for ways to live more environmentally-friendly lives. 

In December, Kerry Health and Nutrition Institute (KHNI) hosted a webinar about how industry can better address wastage while maintaining the high quality that consumers demand.

Earlier this month, another team of scientists reported a new way to extract the protein and fiber from brewer’s spent grain and use it to create new types of protein sources.

There were significant differences in the abundance and type of oligosaccharides in different parts of the marc.

Oligosaccharides attract attention
In addition to being a key component of human breast milk, oligosaccharides are found in many plant and animal tissues. 

However, they appear to be especially abundant in the wine-grape skins. In earlier research, scientists detected oligosaccharides in the finished wine product but not in large concentrations. Sinrod’s team didn’t include bottled wine in this study.

“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,” says Sinrod. 

The researchers point to recent advances that revealed oligosaccharides’ vast potential to support intestinal health as prebiotics continue to trend.

Within the human milk oligosaccharide (HMO) arena, recent advances include Abbott’s findings that they may not only support babies’ immune health, but also their cognitive and motor skill development. 

Meanwhile, Chr. Hansen is eyeing the potential of the Chinese market as approvals for HMOs are underway. 

Edited by Katherine Durrell