Chemical composition and antioxidant capacity of coffee pulp

Abstract

ABSTRACT Coffee pulp is produced in large quantities, and its disposal can pollute the environment. However, the nutritional value and antioxidant content of coffee pulp make it a good option for animal feed. Therefore, the objective of this study was to determine the chemical composition, the phenolic compounds and the antioxidant capacity of coffee pulp using fresh (FCP), ensiled (ECP), and ensiled and sun-dried (EDCP) coffee pulp. The study design was completely randomized with three treatments (n=4). Dry matter (DM), crude protein (CP), ash, acid detergent fiber (ADF), neutral detergent fiber (NDF), lignin, phenolic compounds and antioxidant capacity were determined. Data were analyzed by analysis of variance, and means were compared with the Tukey test. The percentage of CP, NDF and ADF was higher in ECP and EDCP than in FCP. There were no changes in lignin content. Ensiling and sun drying did not decrease (P>0.05) caffeine or tannins. No differences were found in caffeic acid (2.031±2.873, 5.103±0.391, 4.913±0.018 mg g-1 DM in FCP, ECP, EDCP, respectively). The concentration of chlorogenic acid (FCP 2.593±1.756; ECP 5.368±0.422; EDCP 4.875±0.678 mg g-1) increased with the ensiling process, but it was not affected by sun drying. Ethanol decreased in ECP and EDCP relative to FPC (FPC 15.88±0.97%; ECP 7.04±1.16%; EDCP 0.00%); however, antioxidant capacity was not affected. It was concluded that the ensiling process and sun drying affected the nutritional value of coffee pulp but not its antioxidant capacity.