- Brazilian researchers used ultrasound to infuse stingless-bee honey with compounds from discarded cocoa shells, creating a sustainable sweetener with hints of chocolate.
By Emma Bryce
Researchers may have hit on a formula for making two of the world’s most beloved foods even more delectable. By mixing cocoa shells with honey, they have created a heart-healthy product from chocolate industry waste.
The unusual fusion emerged from Brazil, where a large cocoa-growing industry produces vast amounts of cocoa bean husks that mostly end up as waste. Yet the country is also rich in native bee species that produce honey with a less viscous texture than other honeys—which turns out to be exactly the right medium for extracting compounds from other ingredients.
Between the abundant cocoa waste and local honey, the researchers saw an opportunity. Their research combined farm waste donated by the São Paulo state department of agriculture and supply, with five types of honey made by native stingless bees. These were brought together through an unusual experimental method: an ultrasound technology that helps the honey to extract compounds from the cocoa materials that are steeping in it.
That technology works by sending sound waves into the honey, creating bubbles that form and pop, briefly raising its temperature in the process. As the honey’s temperature rises, the heat releases compounds from cocoa husks into the surrounding honey.
With this simple experimental trio, the researchers found that they could extract a significant amount of compounds from the cocoa waste. Specifically, after the ultrasound treatment, the honey was found to be rich in theobromide and caffeine from the chocolate, two ingredients that in moderate quantities have antioxidant and anti-inflammatory effects, and have been linked to better cardiac health.
The results varied by honey type, with honeys that had lower or moderate viscosity—particularly from the bee species known as ‘mandaguari’ and ‘mandaçaia’—able to extract more beneficial compounds from the cocoa shells. The mandaçaia, especially, was able to extract some of the highest theobromine and caffeine yields from the cocoa husks.
The experiments achieved these high extraction levels in an efficient three-and-a-half minutes. And, when the research team ran their techniques through a chemistry sustainability analysis which looked at their methods as well as the footprint of materials used, they found that it scored well, largely because they used local honey that reduced transport impacts.
What’s more, the more heart-healthy honey reportedly tastes delicious, with warming hints of chocolate that the researchers believe could find a home in haute cuisine. The technique could not only give chocolate industry waste a second life, they believe, but could also create a market for this niche new honey amongst local artisanal businesses.
The idea could ripple far beyond Brazil: around 75% of each cocoa pod produced is typically discarded for chocolate-making, leading to an annual 700,000 tons of cocoa waste worldwide. Pairing local honeys worldwide with abundant cocoa husks would put all that wasted flavor to good use. With that in mind, the research team has now patented their chocolate honey, and are looking to commercialize it.
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Rostagno et. al. “Stingless Bee Honeys As Natural and Edible Extraction Solvents: An Intensified Approach to Cocoa Bean Shell Valorization.” ACS Sustainable Chemistry & Engineering. 2025.
Image: © Anthropocene
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