Novel Technique to Check Authenticity of Premium Cacao Beans

Scientists have developed a unique method to authenticate the purity and origin of cacao beans, the source of chocolate’s main ingredient, cocoa.

A cacao tree with fruit pods in various stages of ripening at a botanical garden, Hawaii.

“Cacao (Theobroma cacao L.), the source of cocoa, is an economically important tropical crop. One problem with the premium cacao market is contamination with off-types adulterating raw premium material. Accurate determination of the genetic identity of single cacao beans is essential for ensuring cocoa authentication,” said Dapeng Zhang from the U.S. Department of Agriculture and his colleagues from the Nanjing Agricultural University in China and the University of the West Indies in the Trinidad and Tobago, who published their results in the Journal of Agricultural and Food Chemistry.

“Lower-quality cacao beans often get mixed in with premium varieties on their way to becoming chocolate bars, truffles, sauces and liqueurs.”

“But the stakes for policing the chocolate industry are high. It’s a multi-billion dollar global enterprise, and in some places, it’s as much art as business. There’s also a conservation angle to knowing whether products are truly what confectioners claim them to be.”

The ability to authenticate premium and rare varieties would encourage growers to maintain cacao biodiversity rather than depend on the most abundant and easiest to grow trees.

The team has found ways to verify through genetic testing the authenticity of many other crops, including cereals, fruits, olives, tea and coffee, but those methods aren’t suitable for cacao beans. The scientists wanted to address this challenge.

Applying the most recent developments in cacao genomics, they were able to identify a small set of DNA markers called SNPs that make up unique fingerprints of different cacao species.

The technique works on single cacao beans and can be scaled up to handle large samples quickly.

“To our knowledge, this is the first authentication study in cacao using molecular markers,” the researchers said.

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Wanping Fang et al. 2014. Accurate Determination of Genetic Identity for a Single Cacao Bean, Using Molecular Markers with a Nanofluidic System, Ensures Cocoa Authentication. J. Agric. Food Chem., 62 (2), pp. 481–487; doi: 10.1021/jf404402v