Optimization of Espresso Coffee extraction with different particle size distribution and analysis through GC-MS and HPLC-VWD.

Introduction EC extraction depends deeply on ground and roasted coffee particles produced by the grinding and brewing process. To extract tempting aroma and taste in EC, the grinding process is a crucial step. The taste and flavour change a lot owing to the particle size of grinded coffee [1]. This research aims to optimize and analyse the impacts of different particle size on aroma and bioactive compounds. Methods Quantitative and qualitative analyses were carried out on the two most common coffee cultivars, Arabica and Robusta. Three filters with different particle sizes (200-400 microns) were used for extraction. Volatile compounds analysis was carried out through GC-MS and HPLC-VWD. The usual espresso machine settings (9 bars and 92 °C) were kept to extract EC [2]. Results EC extraction times, kinetics of extraction and its dependence on water pressure and temperature were controlled during the analysis. Volatile compounds, determined in three different filters, were divided into family groups and their characteristics were identified [3]. According to a research study [4] particle size influences the amount of extracted biocomponents in EC. To study the effect of the particle size and extraction in different filters, EC samples were proceeded for analysing caffeine, nicotinic acid and trigonelline. EC extraction were triplicated in the same conditions for each filter and each particle size. The obtained results confirmed a good extraction efficiency of caffeine on 200 microns. Conclusion EC extraction in different filters with different PSD have identified biocomponents and volatiles which can be found in normal EC. EC extraction optimization will be developed by altering net size of filters and further studies will be continued. Novel Aspects The obtained results will give us the opportunity to study different filters in order to develop sustainable and economically feasible EC extraction. 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. [3] Jose A. Sanchez Lopez, Marco Wellinger, Alexia N. Gloess, Ralf Zimmermann, Chahan Yeretzian, "Extraction kinetics of coffee aroma compounds using a semi-automatic machine: On-line analysis by PTR-ToF-MS," International Journal of Mass Spectrometry, vol. xxx, pp. xxx-xxx, 2016. [4] Michael Kuhn, Sandra Lang, Franziska Bezold, Mirjana Minceva, Heiko Briesen, "Time-Resolved Extraction of Caffeine and Trigonelline from Finely-Ground Espresso Coffee with Varying Particle Sizes and Tamping Pressures," Journal of Food Engineering, pp. 30083-3, 2017.