Journal of Food Science
shows that wine grape pomace (WGP), a by-product of winemaking, may be incorporated into baked goods as a good source of polyphenols and dietary fiber. WGP constitutes about 20% of harvested grapes and pinot noir WGP can contain around 39 types of polyphenols, including anthocyanins, hydroxycinnamic acids, catechins, and flavonols. Dietary fiber is also found in high amounts in WGP.
The researchers substituted wheat flour for pinot noir WGP in bread, brownies, and muffins, and evaluated the finished products for total phenolic content, total dietary fiber, and physicochemical and sensory properties. In this study, the combination of wine grape skins and seeds were classified as pomace. A 5%, 10%, or 15% pomace replacement of flour (w/w) for pinot noir WGP was used.
They found that they could achieve a 5.9% and 194.4% increase in polyphenols in pomace fortified breads and muffins, respectively, and a >20% dietary fiber increase, without impacting consumer acceptance of the products. Both breads and muffins were found to be acceptable with a 5% or 10% WGP replacement of flour (w/w) and brownies with 15% WGP replacement based on the physicochemical and sensory characteristics compared to the control. Bread fortified with 10% WGP increased its dietary fiber by 31.61% and total phenolic content by 5.86%, compared to the control. Similarly, muffins fortified with 10% WGP had a 15.02% increase in dietary fiber and a 194.38% increase in total phenolic content, compared to the control. At 15% WGP fortification, brownies had a 6.94% increase in dietary fiber but the total phenolic content actually decreased by 6.04%, compared to the control.
During the sensory testing, panelists commented on the grainy texture of the WGP fortified products. It would be beneficial to produce the baked goods using a smaller particle size in hopes of the pomace being less noticeable when chewed. The smaller WGP particle size might also have an effect on the volume and texture of the baked items as well.
The results of this study demonstrate the feasibility of WGP as an ingredient to increase the content of bioactive compounds in baked goods for promoting human health and the reutilization of the WGP for decreasing waste from winemaking.