Analysis of alpha-dicarbonyl compounds in coffee (Coffea arabica) prepared under various roasting and brewing methods

Abstract

This study investigated the correlations of alpha-dicarbonyl compounds (alpha-DCs), including glyoxal (GO), methylglyoxal (MGO) and diacetyl (DA), formed in coffee prepared under various roasting and brewing methods. The levels of alpha-DCs in Brazilian coffee beans (Coffea arabica) ranged from 28.3 to 178 mu g/mL. Concentration ranges of GO, MGO and DA were 1.31-6.57, 25.5-159 and 1.50-12.9 mu g/mL, respectively. The level of alpha-DCs increased with high roasting temperature, long roasting time, small coffee bean particles, mineral water and espresso brewing. In correlation analysis, the roasting temperature-time showed strong negative correlations with alpha-DCs in espresso (-0.886) and cold-brew coffee (-0.957). In espresso coffee, there was a strong negative correlation between the alpha-DCs and coffee bean particle size (-0.918).