Evaluation of Free- and Bound-Carbonyl Compounds in Craft Beers

Carbonyl compounds (CC) can be formed during the craft beer production process, which influence the sensory properties, in addition to their toxicity. The formation of bound CC, in craft beers, is favored by the high reactivity of these substances. This work aimed to quantify 15 carbonyl compounds, in free and bound forms, in craft beers using hydrolysis (bound CC only) and derivatization reactions. Acetaldehyde concentrations ranged from 8.83 to 466.1 µg L^-1 (free fraction) and 22.47 to 1665 µg L^-1 (bound fraction). Other compounds found were acrolein (free + bound_max.: 2897 µg L^-1), benzaldehyde (free + bound_max.: 1326 µg L^-1), heptanal (free + bound_max.: 1140 µg L^-1) and formaldehyde (free + bound_max.: 97.73 µg L^-1). Craft beers showed a proportion of up to 76% for CC in the bound form, which can be related to undesirable flavors in beverages. The consumption of craft beers containing freeand bound-CC (especially acrolein) could pose a risk to the health of frequent consumers.

Keywords:
carbonyl compounds; craft beer; derivatization; 2,4-DNPH; HPLC-DAD