The amazing thing about coffee is that it consistently delivers on its promises. It contributes to body or mouthfeel sensations, a tactile sensation of liquid in the mouth.
What, however, contributes to the sensation remains a mystery.
Several coffee chemicals have now been identified as contributing to the sense of the beverage coating the inside of the mouth, as well as astringency and chalkiness feelings.
The researchers began by putting together a descriptive analysis panel of chemicals. The chemicals responsible for coffee’s mouthfeel were then separated. They began by evaluating four different coffees. The Specialty Coffee Association has licenced these evaluators, who have given various grades in terms of body. The sensations that differentiated each cup were then illustrated by a separate panel of eight expert tasters who were competent in tactile awareness.
To characterise the mouthfeel of coffee, scientists divided it down into components, allowing them to search for the molecules responsible for such sensations. To distinguish the coffees, four tactile sub-attributes were used: chalkiness, mouthcoating, astringency, and thickness.
Using liquid chromatography, they divided the full-bodied coffee into 12 fractions, which were then tested by a panel of five tasters. If a majority of people ranked a sub-attribute highly in a fraction, the component responsible was further refined.
“We’ve known that coffee can alter textural impressions, and it was generally assumed to be due of sugars and lipids,” said Christopher Simons, Ph.D., one of the project’s co-principal investigators. However, our research team discovered that this sensation might be triggered by tiny chemicals, which is unusual.”
“Knowledge like this could aid producers and growers in producing the best coffee possible. It also could help aficionados attribute certain features of a cup of java to specific compounds, just as wine enthusiasts do.”
Brianne Linne, a graduate student, said, “From our background reading, we found definitions of the coffee body to be very vague, and at times, contradictory, so we thought that this would be an intriguing topic for us to study.”
A cluster of tiny molecules has been discovered to contribute to the mouthfeel of coffee.
Peterson said, “They isolated melanoidin compounds, formed by the Maillard reaction during roasting, and for the first time associated them with astringency. Two compounds, 3- and 4-caffeoylquinic acid, correspond with mouthcoating. Unexpectedly, the sensation subsided with increased concentrations. Although biological responses are multifaceted, it is uncommon for an attribute to be perceived at low levels but not at high levels. Finally, they isolated a novel compound related to chalkiness that contains an amino acid.”
Scientists are not looking forward to determining if mechanoreceptors in the mouth detect these small molecules. They think such receptors could play a vital role in decreasing the mouthcoating sensation that increases caffeoylquinic acid.