Can incorporating grape pomace into bread sustainably enhance its antioxidant capacity?

Bread is a widely consumed staple food worldwide and is a source of carbohydrates and energy in the human diet; however, it usually contains low levels of bioactive compounds, such as polyphenols and dietary fiber. Grape pomace (i.e., the residual skins, seeds, and pulp left after vinification) is rich in dietary fiber and antioxidants and is generated in large quantities worldwide. The use of grape pomace as a food ingredient can offer a promising approach, supported by circular economy and sustainable production principles, to add value to a winery by-product and enhance the nutritional profile of foods. This study investigated the nutritional enrichment of breads by incorporating flour produced from red (cv. Alicante Bouschet) and white (cv. Arinto) grape pomace at three levels (5, 10, and 15% w/w). Breads were produced at a pilot scale, using professional bakery fermentation and baking equipment, and analyzed for protein, lipids, sugars, dietary fiber, total phenolic content, antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl [DPPH] and oxygen radical absorbance capacity [ORAC] assays), color, texture, pH, and consumer acceptance (hedonic test). The control and breads fortified with 15% red grape pomace showed similar patterns in protein, fat, and fiber contents were lowest in the control bread and highest in the bread fortified with 15% red grape pomace (15Red). Grape pomace fortification of bread increased the protein, fat, sugar, fiber, and total phenolic compound contents and antioxidant capacity, providing a sustainable strategy to enhance bread antioxidant capacity. Grape pomace is a sustainable, polyphenol-rich ingredient for bread fortification.