High-value products from ground spent coffee, sunflower, and citrus waste using enzyme technology

Abstract Agri-food waste represents a rich source of bioactive compounds with potential applications in the food, pharmaceutical, and cosmetic industries. This study investigates sustainable strategies for extracting bioactive compounds, with a specific focus on enzyme-assisted extraction (EAE) as an alternative to conventional chemical methods. Spent coffee grounds (SCGs), sunflower residues, and citrus residues were analyzed. Key parameters, including total phenolic content, antioxidant capacity, reducing sugar content, antimicrobial effects, and antiproliferative activity on human cells, were evaluated. SCG and sunflower extracts demonstrated the highest antioxidant content, albeit with minimal variations between enzyme treatments. Notably, enzyme-treated citrus extracts exhibited increased reducing sugar content, significant antimicrobial activity, and inhibition of microbial biofilms. Moreover, citrus extracts were non-toxic to healthy cells while showing pronounced effects against metastatic melanoma cells. These findings underscore the potential of citrus waste as a valuable source of bioactive compounds and highlight EAE as an effective and sustainable extraction technique.