Brown is a healthy colour for coffee beans.
A new UBC study to be published in Food Research International has found that most of the antioxidants found in coffee result from the roasting process that turns the naturally green coffee beans brown.
Previous studies had suggested coffee’s antioxidants came from caffeine or natural antioxidants called chlorogenic acid found in green coffee beans. However, the study conducted at UBC by Yazheng Liu and David Kitts found that the level of antioxidants remained high irrespective of the coffee’s caffeine content and despite a 90% loss of chlorogenic acid from the “Maillard reaction” during roasting.
“Our results clearly show that the Maillard reaction is the main source of antioxidants,” said Liu, a master’s student at UBC’s faculty of land and food systems.
While the study confirms the idea that roasting produces the most antioxidants, further study is needed to determine the optimal level of roasting to produce the highest amount of antioxidants. Some reports suggest dark-roasted beans produce the highest level of antioxidants, while other scientists insist that medium-roasted coffees yield the most.