The Interactions of CO2, Ethanol, Hop Acids and Sweetener on Flavour Perception in a Model Beer

Abstract

Beer is a complex beverage. Beer flavour is a multisensory experience in which, in addition to aroma volatiles, CO 2 , ethanol, bitterness (hop acids) and sweetness all contribute. To investigate the interactions between these fundamental components, a model beer system was developed using representative ingredients. Samples, selected according to a D-optimal design, were assessed by sensory profiling techniques by a trained panel. Predictive polynomial models generated from mean panel data described variations in the attributes as a function of design factors. Results show that CO 2 significantly impacted on all discriminating attributes, including suppression of sweetness and modification of bitterness. A number of complex interactions with design factors showed the effects of CO 2 to be dependent upon component concentration and level of carbonation. CO 2 interacted with hop acids to increase carbonation and tingly perception, which increased linearly with hop acid addition but only at low levels of CO 2 . Ethanol was the main driver of warming perception and complexity. In agreement with other studies, ethanol enhanced sweet perception and also formed some complex interactions with hop acids and CO 2 to modify various attributes, illustrating its ability to interact with both gustatory and trigeminal stimuli. Whether the mechanisms behind these interactions originate at the gustatory periphery or at higher centres in the brain is an area for further investigation. This study provides an in-depth assessment of important flavour components in beer and advances the limited data available on the effects of CO 2 on sensory perception using a commonly carbonated beverage.

Impact of CO2 and its interaction with the matrix components on sensory perception in model cider

“…However, this increase appears to be dependent on polyphenol concentration. An increase in astringency was observed for a low concentration of hop acid but a decrease in its perception was obtained at 600 mL/L of hop acid (Clark et al, 2011).…”

“…Some authors found a decrease in bitterness with CO 2 in beer but only over 300 mL/L of hop acid with an increased bitterness up to 150 mL/L (Clark et al, 2011). ComettoMuniz et al (1987) observed a similar effect on quinine sulfate solution with an increase in bitterness for low concentrations and a decrease for high concentrations.…”

“…Several studies have shown that carbonation leads to a decrease in sweetness (Clark, Hewson, Bealin-Kelly, & Hort, 2011;Cowart, 1998;Hewson, Hollowood, Chandra, & Hort, 2009;Le Calv e, Goichon, & Cayeux, 2008;Passe, Horn, & Murray, 1997;Saint-Eve et al, 2010;Thuillier, 2007) but this decrease is concentrationdependent. For example, Thuillier (2007) observed a significant effect of CO 2 on this attribute but only at 18 g/L and not at 9 g/L or 36 g/L.…”

Brewing Trials of Barley Varieties Registered in the Czech Republic

“…Říz piva je způ-soben rozpuštěným oxidem uhličitým. Je vnímán mechanoreceptory (hmatovými receptory), které jsou aktivovány přítomností bublinek v kapalině a také receptory bolesti, které reagují na konverzi oxidu uhličitého na kyselinu uhličitou, může být ovlivněn hodnotou pH a koloidními látkami v pivu (Clark et al, 2011).…”

“…It is perceived by mechanoreceptors (tactile receptors) which are activated by the presence of bubbles in the liquid, and also by pain receptors that react to the conversion of carbon dioxide to carbonic acid. It can be infl uenced by pH and colloidal substances in beer (Clark et al, 2011).…”