Bioactive properties and nitrite-scavenging mechanism of coffee endocarp extract as a potential functional food ingredient

Coffee endocarp, a by-product of coffee processing, is rich in phenolic compounds and other bioactive constituents. This study investigated the safe and effective utilization of coffee endocarp as a functional raw material in sustainable agriculture. Coffee endocarp was extracted using 80% ethanol and pure water separately, and the antioxidant activity and nitrite-scavenging mechanisms of the obtained extracts were analyzed. Food safety aspects were also assessed through alkaloid and ochratoxin A analyses. Compared with the aqueous extract, the ethanolic extract exhibited higher free-radical-scavenging activity and a higher nitrite-scavenging capacity. Chlorogenic acid served as the predominant phenolic acid in the ethanol (7.5 g/100 g) and water (2.7 g/100 g) extracts and played a key role in nitrite scavenging. This study also explored the potential chemical mechanism of nitrite scavenging. Overall, the research findings highlight the potential of coffee endocarp as a sustainable and safe functional food ingredient. • Coffee endocarp extracts show strong antioxidant and nitrite-scavenging activity. • Ethanol extraction yields higher phenolic content than water extraction. • Chlorogenic acid is the dominant phenolic compound driving nitrite scavenging. • Extracts contain no detectable ochratoxin A and safe levels of caffeine.