Coffee Spent as a Potential Source of Bioactive Compounds

The aim of this research was to evaluate coffee spent as a potential source of antioxidant compounds. 8 brands of coffee capsules, 6 brands of domestic ‘moka’ coffee, and 5 brands of bar coffee were analysed after the brewing process. Extraction was performed using water as a solvent. Total phenolic content, concentrations of caffeine and chlorogenic acids and antioxidant activity were mea- sured. Within each type of coffee spent, the phenolic concentrations and the antioxidant activity showed a great variability. Concern- ing the mean values, the highest phenolic content was found in spent from bar coffee, followed by capsules, and domestic ‘moka’ while the antioxidant activity was in the following decreasing order: capsule, domestic ‘moka’, and bar coffee. Antioxidant activity measured through the DPPH assay was highly correlated with the contents of total phenolic and chlorogenic acids. Caffeine contrib- uted to the antioxidant activity of the extracts.