Changes in composition, antioxidant content, and antioxidant capacity of coffee pulp during the ensiling process

Abstract

The objective of the present study was to determine the nutritive value, the presence of antioxidant compounds, and the antioxidant capacity of coffee pulp ensiled or non-ensiled. Dry matter (DM), crude protein (CP), ash, acid detergent fiber (ADF), neutral detergent fiber (NDF), and lignin, as well as the antioxidant compounds present in coffee pulp and their antioxidant capacity, were determined. A completely randomized design was used. Data were analyzed by analysis of variance. Ensiling of coffee pulp increased the CP content from 98.6 to 111.6 g kg−1 DM, NDF from 414.6 to 519.5 g kg−1 DM, ADF from 383.9 to 439.3 g kg−1 DM, and lignin from 122.9 to 133.6 g kg−1 DM. Caffeine decreased from 5.72 to 5.02 mg g−1 DM. Three antioxidant compounds were detected. Caffeic acid decreased due to ensiling (16.49 vs 14.69 mg g−1 DM). Gallic acid (2.88 vs 2.58 mg g−1 DM) and chlorogenic acid (62.12 vs 56.00 mg g−1 DM) did not differ, and there was similar antioxidant capacity of non-ensiled (215.66 µmol trolox g−1 DM) and ensiled coffee pulp (206.59 µmol trolox g−1 DM). Despite the decrease in the caffeic acid content due to the ensiling process, it is possible to use either ensiled or non-ensiled coffee pulp for animal feeding because of its high antioxidant capacity.