Optimization of extraction variables for espresso coffee

KHAMITOVA, Gulzhan*,**, ANGELONI, Simone*,**, CAPRIOLI, Giovanni*, SAGRATINI, Gianni*, VITTORI, Sauro. *,** *University of Camerino, Camerino, MC, Italy, **International HUB for Coffee Research and Innovation. RATIONALE Espresso coffee (EC) extraction is a convoluted process due to effect on physical and chemical variables to the final cup. Beyond these parameters, size of grinded coffee plays crucial role to extract good espresso with tantalizing aroma, dense cream and mouthfeel flavor [1]. Coffee particles are made by a large number of compounds. An understanding of these compounds can be helpful for process optimization and quality control. This research aims at analyzing the levels of compound variation at specific particle size distribution (200-400 and 400-1000 microns). METHODS Quantitative and qualitative analyses are carried out through HPLC-VWD and GC-MS [2]. The espresso machine settings are maintained at 9 bar and 92±2⁰C. Particle sizes between 200-400 and 400-1000 microns were used to prepare EC. RESULTS EC extraction time, kinetics of extraction and its dependence on water pressure and temperature were controlled during the analysis. Analytes as caffeine, trigonelline, nicotinic acid, chlorogenic acids (CQAs) and volatiles were identified. EC extraction were performed in duplicate for each particle size. Results confirmed a good extraction efficiency of caffeine, which accounted for 170 mg (200-400 microns) and 90 mg per cup (400-1000 microns), respectively. Thus, amount of bioactive compounds was increased extracting smaller particle sizes. CONCLUSIONS & PERSPECTIVES EC extraction of different particle sizes was analyzed for their content in bioactive components and volatiles normally found in EC. Extraction optimization will be developed by modifying extraction variables. REFERENCES [1] Britta Folmer, Imre Blank, Adriana Farah, Peter Giuliano, Dean Sandres and Chris Wille, The Craft and Science of Coffee, London, UK: Elsevier, 2017. [2] Giovanni Caprioli, Manuela Cortese, Gloria Cristalli, Filippo Maggi, Luigi Odello, Massimo Ricciutelli, Gianni Sagratini, Veronica Sirocchi, Giacomo Tomassoni, Sauro Vittori, "Optimization of espresso machine parameters through the analysis of coffee odorants by HS-SPME-GC/MS," Food Chemistry, vol. 135, no. 3, pp. 1127-1133, 2012.