Caffeine is an intensely bitter compound, and coffee beverages can contain caffeine at concentrations far above the human threshold for perceiving bitterness.
A new study from researchers in Germany explains how caffeine’s intense bitterness is masked in our daily cups of caffeinated coffee, allowing us to enjoy a range of tastes and flavors without feeling like we’re biting into a Tylenol.
In short, the roasting process creates molecules called melanoidins that appear to interact with caffeine, reducing its perceived bitterness by about half in the researchers’ sensory tests.
The findings were published June 3 in the American Chemical Society’s Journal of Agricultural and Food Chemistry. The paper was authored by Michael Gigl, Johanna Kreissl and corresponding author Oliver Frank from the Technical University of Munich. The researchers have a track record of investigating how roasting transforms the sensory-related chemistry of coffee.
The paper concludes that the bitterness people perceive in coffee is real, yet it reflects a complex mix of chemical processes and compounds, many shaped by roasting, rather than a simple expression of caffeine alone.
“The significance of this work lies in explaining why coffee beverages do not taste of caffeine, even though the caffeine concentration of coffee is far above the perceivable level,” Gigl said in an announcement from ACS.
Finding the Taste of Caffeine
The research team ran a series of sensory tests with a trained panel. They first compared the bitterness of liquid caffeine in decaffeinated coffee with liquid caffeine in water.
The coffee masked caffeine’s taste so effectively that it took roughly 10 times the amount of caffeine found in a standard brew before the panel perceived it.
To isolate which compounds in coffee were responsible for that masking effect, the researchers tested caffeine in solutions containing additional compounds: chlorogenic acid, which is naturally present in coffee beans, and melanoidins, the large brown molecules produced by the Maillard reaction during roasting.
Source : https://dailycoffeenews.com/
