Scientists from the University of Washington used a century-old observational technique to determine the precise configuration of humulones, substances derived from hops that give beer its distinctive flavour.
The findings overturn results reported in scientific literature in the last 40 years, according to the study published in the journal Angewandte Chemie International.
"Now that we have the right results, what happens to the bitter hops in the beer-brewing process makes a lot more sense," said Werner Kaminsky, a University of Washington research associate professor of chemistry.
There is documentation that beer and its bittering acids, in moderation, have beneficial effects on diabetes, some forms of cancer, inflammation and perhaps even weight loss, researchers said in a statement.
Kaminsky used a process called X-ray crystallography to figure out the exact structure of those acids, humulone molecules and some of their derivatives, produced from hops in the brewing process.
That structure is important to researchers looking for ways to incorporate those substances, and their health effects, into new medicines.
Humulone molecules are rearranged during the brewing process to contain a ring with five carbon atoms instead of six. At the end of the process two side groups are formed that can be configured in four different ways ¿ both groups can be above the ring or below, or they can be on opposite sides.
Which of the forms the molecule takes determines its "handedness," Kaminsky said,