Effects of espresso machine variables on espresso coffee composition.

Introduction Espresso machine variables have a large influence on the levels of bioactive components and on the aroma profile of espresso coffee (EC) [1]. The present contribution will report results of some years of research on this issue, studying electrical (Aurelia) and mechanical (Leva) pump equipped machine. Body This research project aims to assess the levels of aroma components and bioactive compounds such as chlorogenic acids (CGAs), caffeine, trigonelline and nicotinic acid, in different EC extraction conditions (temperature and pressure in two different EC machines). Quantitative analysis experiments were carried out on the two most common coffee cultivars, Arabica and Robusta. EC extraction times, kinetics of extraction and its dependence on water pressure and temperature were controlled during the analysis. Accordingly, the aroma sensory profile was analyzed, using a selected panel of trained sensory judges, in parallel with instrumental analysis. Results demonstrated that the espresso machine settings for the best EC were 9 bars and 88 or 92 °C. The two different espresso machines showed quite different extraction kinetics [2]. Regarding the peculiarity of the two different machines, the total concentration of three CGAs varied considerably, due to their physical parameters. The usual espresso machine settings (9 bars and 92 °C) also the best choice in the extraction of caffeine, trigonelline and nicotinic acid, especially when using Robusta coffee. Conclusion The two different espresso machines had showed quite different extraction kinetics of the EC, with Aurelia machine being more reliable in extracting EC with similar patterns of caffeine, trigonelline and nicotinic acid. EC compositions varied according to the different espresso machine settings. Optimal parameters were set after quantitative and sensory panel assessments. Acknowledgement The research team (School of Pharmacy, University of Camerino), is grateful to Nuova Simonelli (Belforte del Chienti, Macerata, Italy) for providing coffee samples and EC machines and partial economic support. References [1] Maeztu, L., Sanz, C., Andueza, S., De Peña, M.P., Bello, J., Cid, C., 2001. J. Agric. Food Chem. 49, 5437–5444. [2] Caprioli, G., Cortese, M., Cristalli, G., Maggi, F., Odello, L., Ricciutelli, M., Sagratini, G., Sirocchi, V., Tomassoni, G., Vittori, S., 2012. Food Chemistry 135, 1127–1133.