From environmental burden to goldmine: Grape pomace could be harnessed for stilbenes

20 Oct 2021 --- Grape pomace, a by-product of wine-making could benefit the stomach’s biome, intestines and even cardiovascular health, according to a US study carried out by Cornell University.

Though pomace has so far been considered as waste, the research published in Nutrients reveals that it could be a nutritional and environmentally sustainable “goldmine” with numerous applications.

“This research presents a highly relevant opportunity to the food industry, via the inclusion of natural, clean label dietary ingredients that improve intestinal functionality, microbiome and productivity,” Elad Tako, associate professor of food science at Cornell University’s College of Agriculture and Life Sciences, tells NutritionInsight. 

“If we can use the pomace to either extract key compounds or use them as a dietary ingredient to fold into food, then grape pomace can be a very environmentally sustainable source of nutritional compounds with demonstrated health benefits,” he adds.The study found grape pomace had positive, nutritional effects on the intestinal microbiome and small intestine.

Health benefits from by-product waste
The health benefits to the human intestines and stomach’s microbiome are a result of two stilbenes – resveratrol and pterostilbene – which are beneficial molecular compounds found in plants. Red grape skin – and consequently red wine – are a well-known source of resveratrol, dubbed by industry as “the next big thing” for its health properties. 

“While this still needs further research, the findings may play a role in reducing the risks from cardiovascular disease and diabetes,” Tako notes. 

Grape varieties typically found in the Finger Lakes Region of New York were used, where a robust winery economy exists. Specifically, Vitis vinifera wine grapes, Vitis labruscana (concord grapes) and an interspecific hybrid were used. 

Grape industry could turn sustainable
Tako points to data from 2019 showing that around 80% of grapes are used for wine or juice production in New York, with 20% of processed grapes remaining as pomace. 

“Currently, utilization of grape pomace is inefficient as large amounts are produced during harvesting, which increases the concentration per area. The high phenolic amounts decrease the pomace pH and increase resistance to biological degradation, causing environmental concern,” he highlights. 

Reclassifying grape pomace as a co-product that can be reprocessed is a challenge that can be moderately costly on a large-scale level. However, using it as a sustainable source of stilbenes can be beneficial to grape owners and industries, he notes. 

“The utilization of stilbenes extracted from grape pomace presents an opportunity to address the environmental burden that grape pomace presents, '' Tako says.Utilizing the stilbenes found in grape pomace alleviates the environmental burden it currently presents.

Opportunity for industries across the board

The health industry also stands to reap benefits by using the bioactives in various supplements, while food industries can use the bioactives as clean label food product ingredients that promote gut health.

“In addition, we should explore using grape pomace as is, and as a potential dietary ingredient in food products (both human and animal feed), as pomace is high in fiber in addition to stilbenes and polyphenols.”

Previous studies suggested that red-grape pomace could be used for commercial applications, turning the seeds, stalks and skins to other uses like prolonging the shelf life of fatty foods. 

Earlier this year, researchers identified oligosaccharides and other potentially health-enhancing compounds in upcycled wine-grape pomace from grape by-products stemming from California’s chardonnay wine industry.

By Andria Kades