Elimination of tryptamines from green coffee by supercritical CO2 extraction

Abstract

AbstractSupercritical CO2 (SC‐CO2) extraction is commonly used to eliminate caffeine from coffee beans. In this work, the feasibility of tryptamine elimination is considered as a further objective of the process. SC‐CO2 extraction process parameters (eg, pressure, CO2 flow rate, water content) were studied to obtain tryptamine reduction, starting from those used in supercritical decaffeination. A good compromise, in terms of tryptamine residue in coffee beans, and process feasibility and selectivity, was found operating at 280 bar and 0.8 kg/h CO2, at a starting H2O content in coffee beans of 20% w/w. Using these process conditions, a tryptamine residue of 218 ppm (ppm) was measured in coffee beans after 18 hours of processing. A negligible effect on process selectivity and tryptamine yield was obtained by changing the CO2 flow rate and the initial water content. However, working at an initial water content of 30% w/w and using wet CO2 (CO2 plus 3% w/w water), a tryptamine residue of 107 ppm in coffee beans was obtained, but industrial complexity and costs increased.