Chocolate’s distinctive and beloved flavor may lead to insights into the origin of the solar system and even life itself. University of Hawaiʻi at Mānoa chemists have definitively created and identified three chocolate flavor molecules under conditions that simulate how such molecules might form in the cosmos. The new research takes scientists a step closer in their quest to understand how the solar system and Earth formed, and how life began. The study was published in the journal ChemPhysChem.
“Our team used unique methods to mimic how molecules in interstellar ices could be transformed by ionizing radiation from galactic cosmic rays,” says Matthew J. Abplanalp, a chemistry doctoral student in the Department of Chemistry, College of Natural Sciences. “To our surprise, three of the molecules we created contribute to the taste and flavor of chocolate here on Earth.”
One of these molecules had tentatively been detected by astronomers in star- and planet-forming regions as well as in comets, but scientists were unclear how they might have formed.
To our surprise, three of the molecules we created contribute to the taste and flavor of chocolate here on Earth.
—Matthew J. Abplanalp
“Our research shows that these kinds of molecules can be synthesized easily within interstellar ices at temperatures as low as -450 °F in molecular clouds and are predicted to be ubiquitous in space,” says Professor Ralf I. Kaiser, Abplanalp’s advisor. Kaiser developed the technique used to create and identify specific molecules. “Our method identifies isomers of molecules with 100 percent accuracy,” which has not been possible by previous methods such as traditional infrared spectroscopy.
The chocolate flavor molecules Kaiser’s team detected were of propanol and butanal. Propanol and butanal are complex organic molecules (COMs)—substances containing six or more atoms of hydrogen, carbon, nitrogen and oxygen. COMs account for a third of the more than 200 molecules detected by astronomers in the interstellar medium, the matter that exists in the space between stars. COMs are the building blocks of more complex molecules essential to life, and astronomers have long sought an explanation for their formation. The ices used in the experiments were composed of carbon monoxide—a molecule very toxic on Earth—and methane and were chosen to explore the proof of concept that chocolate-related molecules can be synthesized in deep space.
Abplanalp reported that the team is now planning to use more complex ices containing nitrogen and phosphorous. “The phosphorous-based ices will have importance for understanding how RNA, DNA and ATP may have formed,” he says. ”The nitrogen-containing ices could form molecules of relevance to amino acids, for example.” All of which should ultimately give Abplanalp and Kaiser a deeper understanding of the origins of life in the universe.
