Coffee beans roasted till dark brown produces valued antioxidants

Washington: A study by food scientists has found that when coffee is roasted to a dark brown it produces very valuable antioxidants.

Researchers at the University of British Columbia have been able to trace the complex chemistry behind coffee’s much touted antioxidant benefits, and they found it all depends on the roasting process.

Lead author Yazheng Liu and co-author 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 analysed the complex mixture of chemical compounds produced during the bean’s browning process, called the “Maillard reaction”.

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.

Antioxidants aid in removing free radicals, the end products of metabolism which have been linked to the aging process.

“Previous studies suggested that antioxidants in coffee could be traced to caffeine or the chlorogenic acid found in green coffee beans, but our results clearly show that the Maillard reaction is the main source of antioxidants,” Liu, an MSc student in the Faculty of Land and Food Systems (LFS) said.

“We found, for example, that coffee beans lose 90 percent of their chlorogenic acid during the roasting process,” Kitts, LFS food science professor and director of the Food, Nutrition and Health program, added.

The UBC study sheds light on an area of research that has yielded largely inconsistent findings.

While some scientists report increased antioxidant activity in coffee made from dark roasted beans, others found a decrease. Yet other theories insist that medium roast coffees yield the highest level of antioxidant activity.

Their findings will appear in a forthcoming issue of Food Research International.

Food in early life affects fertility

A new research by the University of Sheffield has revealed that the reproductive success of men and women is influenced by the food they receive at an early stage in life.

The research is the first study of its kind to show that early life food can have a serious influence on the life-long fertility of individuals.

The research team, led by Dr Ian Rickard from the Department of Animal and Plant Sciences at the University, used a combination of church record data on births in 18th century Finland and agricultural data on crop yields of rye and barley from the same time and place.

The study showed that in men and women born into poor families, food in very early life was related to the probability of reproducing. Approximately half of the poor people who were born in a year in which both rye and barley yields were low would not go on to have any children during their entire lives. However almost everyone from a poor family born in bumper harvest years, when both crops were high, would reproduce at least once in their life.

These results indicate that food received during prenatal or early postnatal life may limit the development of the reproductive system.

Rickard said: "Our results show that the food received by children born into poor families had an influence on their later reproductive success. These results have implications for our understanding of early environmental effects on human and animal health and will help shed light on our current understanding of fertility and whether it is influenced by individual or social factors."

The research has been published in the journal Ecology.