Coffee Chemistry: monitoring and analyzing the degradation of 5-caffeoylquinic acid during roasting.

Coffee is one of the most widely consumed beverages in the world, but not all is known regarding what happens on a chemical level during the roasting of green coffee beans. There is one group of compounds in particular whose volatile degradation products are poorly characterized. This group of esters is referred to as chlorogenic acids, make up between three and eight percent of green (unroasted) coffee beans by dry mass, depending on the type of bean (Arabica or Robusta) and its origin. We studied the degradation pathway and products of 5-caffeoylquinic acid that occurs during roasting using mid-IR spectroscopy.  Our results suggest that the gaseous products of 5-CQA  have carbonyl moieties that continue to emerge well beyond melting point of 5-CQA. We intend to use these data and future experiments to inform the degradation mechanism of 5-CQA, thereby bridging a gap in existing knowledge of the impacts of roasting on coffee’s chlorogenic acids.