Wine grape pomace can be used to increase the antioxidant and dietary fiber content in breads, muffins and brownies, find researchers.
In research published in the Journal of Food Science, a team from Oregon State University in the US fortified a host of baked goods with red wine grape (Pinot Noir) and white wine grape (Pinot Grigio) pomace - the skins and seeds left after the pressing step of the winemaking process.
Findings showed both red and white wine grape waste increased the total phenolic and dietary fiber content of the baked goods as well as the radical scavenging activity.
Dietary fiber could be increased by more than 20% and polyphenols by 5.9-194.4% in breads and muffins without impacting consumer acceptance.
“The results of this study demonstrated the feasibility of wine grape pomace as an ingredient to increase the content of bioactive compounds in baked goods for promoting human health and the reutilization of the wine grape pomace for decreasing waste from winemaking,” the researchers said.
Wine pomace constitutes about 20% of harvested grapes, they said.
Making use of waste in its natural form
The wine grape pomace contained high levels of dietary fiber and polyphenols, the researchers explained, even after the winemaking process.
“A majority of the polyphenols from red wine grapes remain in the skins and seeds after pressing lending the pomace as an excellent source of polyphenols. In addition, by using the pomace in its natural form instead of as an extract, there is a higher retention of polyphenols and their synergistic effects.”
For breads fortified with 10% red wine grape pomace, dietary fiber increased 31.61% and 5.86% in total phenolic content.
Muffins fortified with the same level of red wine grape pomace saw a 15.02% increase in dietary fiber content and a 194.38% increase in total phenolic content.
The researchers fortified brownies with 15% pomace, leading to a 6.94% increase in dietary fiber but a decrease of 6.04% in total phenolic content.
Hitting the senses just right…
The researchers acknowledged that wine grape pomace in baked goods could impact taste, color and texture.
However, consumer testing indicated Pinot Noir pomace could replace wheat flour at 5% in bread, 10% in muffins and 15% in brownies without negatively impacting the overall sensory characteristics.
Despite this, researchers acknowledged that mouth feel and color were impacted but added there were strategies to counter this.
Panelists commented on the grainy texture of the red wine grape pomace, but the researchers said if used in baked goods with smaller particle sizes it could reduce noticeability when chewed.
Similarly color change was observed in all baked goods, with red wine grape pomace adding a dark red to breads and muffins and even darker tone to brownies.
This could be off-putting for consumers, the researchers said, as baked goods were not traditionally red without food coloring. But, darker baked goods were also often associated with healthier attributes like increased fiber and whole grain content, they said, and so if manufacturers drew attention to the pomace content and increased fiber levels, the color may not deter consumers.
Source: Journal of Food Science
Published online ahead of print, doi: 10.1111/1750-3841.12554
“Physiochemical, Nutritional, and Sensory Qualities of Wine Grape Pomace Fortified Baked Goods”
Authors: R. Walker, A. Tseng, G. Cavender, A. Ross and Y. Zhao