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

Abstract

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 (boundCC 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 + boundmax.: 2897 µg L-1), benzaldehyde (free + boundmax.: 1326 µg L-1), heptanal (free + boundmax.: 1140 µg L-1) and formaldehyde (free + boundmax.: 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 free- and bound-CC (especially acrolein) could pose a risk to the health of frequent consumers.

Effect of Wort Boiling System and Hopping Regime on Wort and Beer Stale-Flavor Aldehydes

“…Various off-flavors have been attributed to individual carbonyls, most of which have a threshold higher than that of fresh beer [ 14 ]; due to synergistic effects, many stale-flavor compounds act as aroma compounds even at low concentrations [ 11 ]. In addition, a significant proportion of aldehydes may be bound in complexes, and currently Acácio et al [ 26 ] report 70% bound carbonyls in craft beers. Wort produced by the pressurized wort boiling system with higher aldehyde levels may result in less sensory stable beers.…”