Upcycling Chardonnay grapes: Sonomaceuticals and UC Davis spotlight health benefits

30 Apr 2024 --- Grape marc or pomace is a substantial waste product of the wine industry, making up around 30% of the grape weight. US-based Sonomaceuticals upcycles the marc of Chardonnay grapes — one of the most abundant grapes of California — into its WellVine ingredient with F&B and supplement applications, such as the company’s Vine to Bar premium chocolate.

Research on the marc’s health benefits and bioactive compounds is supported by the University of California (UC) Davis, US. Nutrition Insight meets with professionals from Sonomaceuticals and researchers from UC Davis to discuss Chardonnay marc’s health and sustainability advantages and the company’s Vine to Bar chocolate. 

Sonomaceuticals has been looking at the grape byproduct for over ten years, explains Fanny Lee, Ph.D., research program manager at Sonomaceuticals. “We only started looking at the seeds, milling them into flour.” 

“When Scott Forsberg joined, he said we can’t just do seed; we have to do the whole product because if we just do the seed, we still have another waste stream, another byproduct. He’s been a big advocate of using the whole material.”

The company worked with the USDA Agricultural Research Service to compare different varieties of seed flour based on several grapes. After doing animal trials, the researchers found a big difference between red and white wines, says Lee. “Specifically, Chardonnay significantly impacted lipids, glucose and the microbiome. That was the big reason why we charged forward with the Chardonnay.” 

In her dissertation, she researched the impact of human consumption of the material, finding positive impacts “similar to what we saw in the rodents.” Since then, the company focused on the whole marc. 

Lee underscores that part of the company’s success lies in creating a product and market while conducting research. “We’re doing everything simultaneously.” 

Chocolate trifecta 
As a winemaker and chocolate maker expert, Ralph Jerome, head of innovation at Vine to Bar, was intrigued about the idea of upcycling Chardonnay grape pomace. “When you make Chardonnay, you de-stem and then crush and press the grapes — the grapes in that press are pristine; they just come out of the field.” 

He made a pilot product with the first raw materials and was happily surprised by the chocolate quality. 

Grape marc is a substantial waste product of the wine industry, making up around 30% of the grape’s weight.He underscores one of the great stories about chocolate — the flavanol content. The consumer takeaway is that “dark chocolate is good for you because it has cocoa flavanols.” Combining it with Chardonnay marc results in a “beautiful range of polyphenols” in the product, giving it an interesting nutritional benefit. 

“One of the things I learned through years of looking at sustainability programs is that sustainability doesn’t sell. People buy for taste, health and combinations of taste and health, but the sole benefit of a product can’t be sustainability, especially if you have to upcharge for sustainability.”

Jerome highlights: “It seemed right away that there was potential for the health story, which is always compelling, especially if you link it to other things. It seemed like there could be a taste story. And it has this benefit of sustainability, which helps you differentiate from other great tasting products.” 

“When you have this matrix of three things, this trifecta, it creates a great potential proposition.”

Bioactive compound research  
Daniela Barile, a professor at UC Davis food science and technology, evaluates the bioactive compounds of Chardonnay grape marc. She tells Nutrition Insight that literature on phenolic compounds supports the role of grape marc in the gut microbiota and suppressing pathogens. However, she argues that this benefit does not solely stem from phenolics. 

“When you do studies in vitro or with animals, people were not aware of the existence of oligosaccharides because people were not separating them. They were doing a process to isolate phenolics.” 

“Everything has been attributed only to phenolics so far,” she continues. While the pathogen suppression can be attributed to phenolics, the prebiotic and “the stimulation of the growth of Bifidobacteria and lactobacilli could be the oligosaccharides. Because oligosaccharides are an excellent carbon source.” 

“We looked at the structures and discovered they have the same polarity as oligosaccharides — binding to the same material, they have the same molecular weight.” 

Barile explains that the research team developed a protocol to separate oligosaccharides from phenolics and study them separately.Barile explains that there is no single standard for oligosaccharides for grape marc because these are new molecules. The compounds are much more complex to study than phenolics because they are complicated to characterize. So far, phenolics and oligosaccharides have only been studied together. 

“We developed a protocol to separate them and then study them in vitro, separately, on the microbiota,” she explains. “It’s key that analytics and engineering go hand in hand to develop the methods and then study both in vitro and in vivo. Of course, in vivo is the future, and in vitro is today the reality of creating novel functional ingredients that can help the population.”

Grape marc oligosaccharides 
Oligosaccharides are derived from polysaccharides in the cell wall of the grape; these are partially broken down during grape maturation. Barile explains that chocolate does not contain oligosaccharides. Adding the grape marc brings in a new compound. 

“They’re important because they’re non-digestible. The human body does not have the enzymes to break them down.”

She highlights that oligosaccharides are known to be prebiotic. “The selectivity of how many bacteria can consume them will depend on the structure, and that’s why we need chemistry to study them.” 

Common prebiotics, such as inulin, consist of a repetition of fructose. Many bacteria can possess the enzyme to break down the linkages. “The more building blocks you have and the more different arrangements, the more selective because fewer bacteria will have those enzymes.” 

“Evolutionarily, we have learned from studying breast milk that a higher diversity of building blocks means that beneficial bacteria are going to have that complex of a genome.” 

For example, she explains that Bifidobacteria have 30% more genomes than other bacteria, which are dedicated to genes that make enzymes to break down oligosaccharides. “They make transporters like private fingerprint elevator doors that only open for those building blocks. They don’t leave anything behind for pathogens to consume.”  

The Vine to Bar chocolate is a proof of concept that Chardonnay marc can make delicious and nutritious things.Product applications  
Jerome sees the Vine to Bar chocolate as a demonstration product — a proof of concept that Chardonnay marc can make delicious and nutritious things, demonstrating that the raw material can be successfully upcycled. “To Sonomaceuticals and me, it’s the tip of the iceberg from an application perspective.

He highlights that the company has a patent for Chardonnay, which uses juiced fruit in chocolate to improve the flavor. 

“We have two dietary supplements coming out,” adds Lee. “We’re doing a cocoa and WellVine combination in a powder form.” 

The company made this ingredient available to customers after receiving a lot of interest from food manufacturers in buying WellVine and using it in different applications. 

Jerome notes there are many opportunities for the product, including fruit candy, roll-ups, gummies or smoothies. “Wherever you use a dry powdered fruit or a puree, this would be a great addition. It has a significantly lower sugar content than most purees. If you take a grape and take out the water, it’s 85% sugar or in that vicinity. We’re only about 20% sugar.” 

By Jolanda van Hal