Spent coffee that is produced in tons by restaurants and cafeterias, and consumers at domestic levels, could be a
good opportunity to have an important source of natural antioxidants. The main aim of this work was to study
the influence of several process factors on the antioxidant capacity extraction from spent coffee. Total phenolic
compounds, radical scavenging activity (ABTS and DPPH) and browned compounds (Abs 420 nm) of spent
coffee extracts obtained with continuous (Soxhlet 1 h and 3 h) and discontinuous methods (solid–liquid
extraction and filter coffeemaker), several solvents (water, ethanol, methanol and their mixtures), successive
extractions, and water with different pHs (4.5, 7.0 and 9.5) were carried out. Spent coffee extracts with the
highest antioxidant capacity were obtained after one extraction with neutral water (pH 7.0) in a filter
coffeemaker (24 g spent coffee per 400 mL water). Furthermore, spent coffee defatting and extract
lyophilization allowed us to obtain spent coffee extracts powder with high antioxidant capacity that can be
used as an ingredient or additive in food industry with potential preservation and functional properties.