Chemical Composition, Antioxidant Compounds and Antioxidant Capacity of Ensiled Coffee Pulp

Abstract

Coffee pulp is produced in large quantities and its disposal can pollute the environment. However, its nutritional value and antioxidant content make it a good option for feeding animals. Therefore, the objective of this study was to determine the chemical composition, the presence of phenolic compounds and the antioxidant capacity of coffee pulp: fresh (FCP), ensiled for 140 days (ECP), and ensiled for 140 days and sun dried (EDCP). Dry matter (DM), crude protein (CP), ash, acid detergent ber (ADF), neutral detergent ber (NDF), lignin, phenolic compounds and the antioxidant capacity of FPC, ECP and EDCP were determined. Data were analyzed by analysis of variance, and means were compared with the Tukey test. The percentage of CP, FDN and FDA was higher (P<0.05) in ECP and EDCP than in FCP (CP: 10.85, 13.10, 13.24; NDF: 49.33, 50.95, 55.18; ADF: 41.90, 46.60, 52.14). There were no changes (P>0.05) in lignin content (FCP 30.97 %, ECP 31.25 %, EDCP 31.50 %). Ensiling and sun drying did not decrease (P>0.05) caffeine or tannins in coffee pulp. No differences (P>0.05) were found for caffeic acid (2.03, 5.10, 4.913 mg g-1 DM in FCP, ECP and EDCP, respectively). Chlorogenic acid (2.59 FPC; 5.36 ECP; 4.87 EDCP mg g-1) increased (P<0.05) in concentration with the ensiling process, but it was not affected by sun drying. Ethanol decreased (P<0.05) in ECP and EDCP, relative to FPC (FPC 15.88 %; ECP 7.04 %; EDCP 0.00 %), while antioxidant capacity was not affected (P>0.05) (FCP 2594.7; ECP 2486.3; EDCP 2769.9 nmol Trolox-1 mL). It is concluded that the ensiling process and sun drying did not affect the nutritional value or antioxidant capacity of coffee pulp.