Thursday, February 3, 2011

Maillard reaction is the principle contributor to the antioxidant capacity of coffee brews ......

Food scientists at the University of British Columbia have been able to pinpoint more of the complex chemistry behind coffee's much touted antioxidant benefits, tracing valuable compounds to the roasting process.  Yazheng Liu and Prof. David Kitts found that the prevailing antioxidants present in dark roasted coffee brew extracts result from the green beans being browned under high temperatures.

Liu and Kitts analyzed the complex mixture of chemical compounds produced during the bean's browning process, called the "Maillard reaction (a chemical reaction between an amino acid and a reducing sugar, usually requiring heat). The term refers to the work by French chemist Louis-Camille Maillard who in the 1900s looked at how heat affects the carbohydrates, sugars and proteins in food, such as when grilling steaks or toasting bread. Previous studies suggested that antioxidants in coffee could be traced to caffeine or the chlorogenic acid (see structures above and below respectively)  found in green coffee beans, but the present results clearly show that the Maillard reaction is the main source of antioxidants claims the researchers.  Researchers conclude that that coffee beans lose 90 per cent of their chlorogenic acid during the roasting process, LFS food science professor and director of the Food, Nutrition and Health program.

Ref : Yazheng Liu and David D. Kitt, Food Research International.

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