The scientists visualized the accumulation of cadmium in cocoa beans. This was reported by the Helmholtz Center for Materials and Energy in Berlin.
Cocoa plants absorb toxic heavy metals that can slowly poison groundwater and soil if soils are contaminated, such as by mining. At the same time, cocoa is mainly grown in equatorial countries, many of which do not comply with strict environmental standards and where agricultural regulations are rife with fraudulent schemes. At the same time, it is not clear exactly where toxins accumulate in the fetus – in the shell or in the endosperm inside.
Joanna Mantuvalu and colleagues visualize accumulation of the heavy metal cadmium in cocoa beans. They examined cocoa samples from Colombia that were contaminated with an average of 4.2 mg/kg of cadmium. This is well above the European limits of 0.1-0.8 mg cadmium/kg in cocoa products.
“There was little understanding of how cadmium migrates from the soil to plants through roots and where the element accumulates in beans. It is impossible for scientists to accurately localize the cadmium content in a non-invasive way,” he explains.
In conclusion, they used three X-ray fluorescence methods for visualization and it was particularly difficult to reach a conclusion as the cadmium signal was suppressed by similar signal of potassium, which is abundant in fruits. As a result, it turned out that cadmium accumulates mainly in the outer shell and has little penetration into the endosperm. In addition, this distribution is significantly affected by roasting, and the authors hope that by changing the processing technology, it will be possible to minimize the cadmium content in the final product, even if the fruits are obtained from an infected plantation.
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