Apple and grape pomace: emerging upcycled functional ingredients in processed meat products, designed to increase polyphenol and fiber contents†

Apple and grape pomace, byproducts of juice, cider, and wine production, are typically sent to landfills or used as animal feed. At landfills, they release greenhouse gases like methane and carbon dioxide during anaerobic digestion. These pomaces are rich in fiber (31.79–61.71%) and polyphenols, which are lacking in the western diet, particularly in widely consumed meat-based food products. This review aims to explore the current literature that discusses the effects of incorporating apple and grape pomace into meat, focusing on fiber enrichment, prevention of lipid oxidation, and sensory characteristics like color, flavor, and texture. This narrative review consolidates findings from research databases to provide a structured synthesis of current knowledge on the topic. The polyphenols in pomace are as effective as synthetic antioxidants in reducing lipid oxidation. However, high pomace levels can increase meat hardness. Including pomace in meat products could reduce waste, minimize landfill contributions, and enhance meat's nutritional and functional properties.