Cocoa solids are one of the richest sources of polyphenol antioxidants. Cocoa undergoes several steps before it takes shape as a chocolate bar. The process involves roasting, which brings out the flavor. But some of the healthful polyphenols are lost during the roasting process. With an aim to retain as much of the polyphenols and good flavors as possible, scientists are now working on making chocolate treats more nutritious.
Resaercher Emmanuel Ohene Afoakwa, University of Ghana, said, "We decided to add a pod-storage step before the beans were even fermented to see whether that would have an effect on the polyphenol content."
The research team divided 300 pods into four groups that were either not stored at all or stored for three, seven or 10 days before processing. This technique is called 'pulp preconditioning'. After the storage period passed, fermentation and drying were done as usual. Researchers found that the seven-day storage resulted in the highest antioxidant activity after roasting.
The researchers also studied the effects of roasting at the same temperature for different times. The current process involves roasting the beans for 10-20 minutes at 248-266 degrees Fahrenheit. The research team adjusted this to 45 minutes at 242 degrees Fahrenheit and discovered that this slower roasting at a lower temperature increased the antioxidant activity compared to beans roasted with the conventional method.
"In addition, the beans that were stored and then roasted for 45 minutes had more polyphenols and higher antioxidant activity than beans whose pods were not stored prior to fermentation. The pulp preconditioning likely allowed the sweet pulp surrounding the beans inside the pod to alter the biochemical and physical constituents of the beans before the fermentation, which aided the fermentation processes and enhanced antioxidant capacity of the beans, as well as the flavor," said Afoakwa.
The research will be presented at the 249th National Meeting and Exposition of the American Chemical Society (ACS).