For every chocolate bar the world consumes, the industry leaves behind a mountain of waste. We’re talking about the cocoa bean shell — the tough outer skin that usually ends up in a landfill.
But we’re throwing away a nutritional goldmine. Those discarded shells are packed with theobromine and caffeine, the very compounds that give cocoa its kick. The trick, until now, has been getting those nutrients out without ruining them.
Now, a team from Brazil found a way to rescue those compounds without using a single drop of toxic chemicals. Their secret weapon is a group of native, stingless bees and a device that “screams” at honey with high-intensity sound waves.
A Messy Business
Global cocoa production generates millions of tons of shells annually. While these shells are loaded with stimulants, getting those nutrients out is usually a nightmare. Traditional methods tend to use high heat, long hours, and harsh organic solvents. None of those are sustainable, and they’re not particularly cheap methods either.
The researchers at the University of Campinas (UNICAMP) decided to try a different approach. What if the solvent was the product?
Enter the bees.
The honey you find in supermarkets isn’t a particularly good solvent. But different bees make different types of honey. In particular, the native Brazilian bees the researchers worked with are master chemists. They create honey that is thinner, more acidic, and bursting with antioxidants.
The team gathered honey from five distinct species:
- Borá (Tetragona clavipes)
- Jataí (Tetragonisca angustula)
- Mandaçaia (Melipona quadrifasciata)
- Mandaguari (Scaptotrigona postica)
- Moça-branca (Frieseomelitta varia)
Then, they had to figure out how to force the cocoa shells to give up the nutrients.
A Sound Jackhammer
If you simply put cocoa residue in honey, you won’t dissolve very much of it. You can try to heat it up, but then you end up with something similar to the original inefficient method. So, instead, researchers used a high-intensity probe that they dipped directly into the mixture.
This probe vibrates 20,000 times per second (20 kHz). These vibrations create millions of microscopic bubbles that grow and then violently collapse. This process, called cavitation, acts like a tiny jackhammer, shredding the cellular structure of the cocoa bean shells and forcing the theobromine and caffeine out into the honey.
The results were staggering. In just 3.5 minutes, the researchers were able to pull more nutrients out of the shells than traditional methods do in nearly an hour.
The resulting product isn’t just a lab experiment — it’s delicious.
“Of course, the biggest appeal to the public is the flavor, but our analyses have shown that it has a number of bioactive compounds that make it quite interesting from a nutritional and cosmetic point of view,” says Felipe Sanchez Bragagnolo, the study’s first author. He carried out the research during his postdoctoral work at the Faculty of Applied Sciences (FCA) at UNICAMP in Limeira with support from FAPESP.
A Rare Win-Win
Beyond the science, there’s another benefit. These bees are part of the cultural heritage of traditional and native communities in Brazil, Malaysia, and Australia. By finding industrial uses for their honey, scientists are creating economic incentives to protect the forests where these bees live. It is a rare win-win for science and conservation.
But scientists say other types of honey should work. They encourage others to experiment and try the same technique with locally sourced honeys.
The team concludes on a positive note: you don’t need to operate this in industrial quantities. Even small businesses should be able to make a sustainable and healthy profit with this method.
“We believe that with a device like this, in a cooperative or small business that already works with both cocoa and native bee honey, it’d be possible to increase the portfolio with a value-added product, including for haute cuisine,” suggests Professor Mauricio Ariel Rostagno, a co-author of the study.
Journal Reference: Bragagnolo et al, Stingless Bee Honeys As Natural and Edible Extraction Solvents: An Intensified Approach to Cocoa Bean Shell Valorization. ACS Sustainable Chemistry, 2025; 13 (37): 15372 DOI: 10.1021/acssuschemeng.5c04842