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Technique discovered for healthier, sweeter chocolate

Researchers from Ghent University in Belgium and the University of Ghana have discovered a way to make chocolate more nutritious – and sweeter.

The technique used by the scientists involves roasting the cacao beans at a lower temperature and leaving bean pods unopened for five days rather than split open right away.

Roasting the cocoa beans brings out the flavour, but some of the healthful polyphenols (antioxidants) are lost during the roasting process, so the researchers wanted to figure out a way to retain as much of the polyphenols and flavours as possible.

“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,” said Emmanuel Ohene Afoakwa, Ph.D., University of Ghana.

“This is not traditionally done, and this is what makes our research fundamentally different. It’s also not known how roasting affects polyphenol content.”

Afoakwa’s 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 each storage period passed, fermentation and drying were done as usual. He reports that the seven-day storage resulted in the highest antioxidant activity after roasting.

To assess the effects of roasting, the researchers took samples from each of the storage groups and roasted them at the same temperature for different times. The current process is to roast the beans for 10-20 minutes at 248-266 degrees Fahrenheit. Afoakwa’s 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. Afoakwa said 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.

“This aided the fermentation processes and enhanced antioxidant capacity of the beans, as well as the flavour,” he said. Afoakwa explained at a press conference that the new technique would be particularly useful for countries in Southeast Asia and Latin America where cocoa beans produce a chocolate with a less intense chocolate flavour and have reduced antioxidant activity.

The team will now study in more detail the effects of roasting on the flavour of freshly picked compared to stored cocoa beans. They will be testing different temperatures and roasting and storing times to determine if even higher amounts of antioxidants can be retained through the process.

A paper describing the research was published in the African Journal of Food, Agriculture, Nutrition and Development.

 

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