Espresso spent coffee grounds were chemically characterized to predict their potential, as a source of bioactive compounds,
by comparison with the ones from the soluble coffee industry. Sampling included a total of 50 samples from 14 trademarks, collected in
several coffee shops and prepared with distinct coffee machines. A high compositional variability was verified, particularly with regard to
such water-soluble components as caffeine, total chlorogenic acids (CGA), and minerals, supported by strong positive correlations with
total soluble solids retained. This is a direct consequence of the reduced extraction efficiency during espresso coffee preparation, leaving a
significant pool of bioactivity retained in the extracted grounds. Besides the lipid (12.5%) and nitrogen (2.3%) contents, similar to those
of industrial coffee residues, the CGA content (478.9 mg/100 g), for its antioxidant capacity, and its caffeine content (452.6 mg/100 g),
due to its extensive use in the food and pharmaceutical industries, justify the selective assembly of this residue for subsequent use.
