A new way to combine your favourite milk chocolate with peanut skins and coffee waste can boost its antioxidant properties, thereby providing the same health benefits associated with the harder, more bitter dark chocolates, says a study. The results suggest that you may not have to compromise on the taste to get the benefits of dark chocolate which has high levels of phenolic compounds.
Peanut skins are not the only food waste that can enhance milk chocolate in this way.
The researchers are also exploring the extraction and incorporation of phenolic compounds from used coffee grounds, discarded tea leaves and other food scraps.
"The idea for this project began with testing different types of agricultural waste for bioactivity, particularly peanut skins," said Lisa Dean, the project's principal investigator from the US Department of Agriculture (USDA).
"Our initial goal was to extract phenolics from the skins and find a way to mix them with food."
When manufacturers roast and process peanuts to make peanut butter, candy and other products, they toss aside the papery red skins that encase the legume inside its shell.
Thousands of tonnes of peanut skins are discarded each year, but since they contain 15 per cent phenolic compounds by weight, they are a potential goldmine of antioxidant bioactivity.
"Phenolics are very bitter, so we had to find some way to mitigate that sensation," Dean said.
In fact, the natural presence of phenolic compounds is what gives dark chocolate its bitterness, along with less fat and sugar compared to its cousin milk chocolate.
To create their antioxidant-boosted milk chocolate, Dean and her team of researchers at the USDA worked with peanut companies to obtain the peanut skins.
From there, they ground the skins into a powder, and extracted the phenolic compounds with 70 per cent ethanol.
They also worked with local coffee roasters and tea producers to obtain used coffee grounds and tea leaves, using a similar methodology to extract the antioxidants from those materials.
The phenolic powder was then combined with maltodextrin, a common food additive, to make it easier to incorporate into the final milk chocolate product.
The researchers presented their results at the American Chemical Society (ACS) Fall 2020 Virtual Meeting & Expo.