Scientists say they have figured out how to identify the genetic origin of the cacao fruit, a finding that should help put a damper on counterfeit chocolate.
As the worldwide demand growing for ultra-premium chocolate made from top-quality cacao beans has risen, so too has the practice of blending in cheaper substitutes for the good stuff. The problem is that unlike coffee, grapes, cereals and tea, which can be subject to existing methods of genetic testing to verify their origins, cacao has been a tougher nut to crack.
Researchers at the USDA's agricultural research station in Greenbelt, Md., figured out how to overcome this problem using small SNPs or single nucleotide proteins ("snips") that make up unique fingerprints of different cacao species and hybrid varieties.
The technique works on single cacao beans and can be scaled up to handle large samples quickly, according to Dapeng Zhang, a research geneticist at the USDA and lead author of a new paper that recently appeared in the Journal of Agricultural and Food Chemistry.
“In the premium cacao market, often the good varieties are the traditional varieties,” he said. “They typically don’t have a very high yield, but their quality is highly appreciated. The buyers offer a higher price for these kind of beans and during this process, either the grower or middleman intentionally or unintentionally mix high quality bean with bulk cacao, which is an average bean.”
Zhang, who worked at a cacao research center in Peru for a decade, decided to use the seed coat of the cacao bean to extract the DNA needed to make a positive identification of the plant's origins. Zhang and colleagues successfully identified the location of the type of cacao trees grown in the Cajamarca Province of Peru as compared to the kind of cacao grown in other parts of Peru, Brazil, Trinidad and Ecuador. The next step is getting the genetic test to handle larger numbers of samples, and to be used by buyers in the field, Zhang said.
But one expert noted that devising a genetic test won’t make the chocolate taste any better.
“It’s going to cost a lot of money for a company to (test),” said Louis Grivetti, a professor emeritus of nutritional sciences at the University of California, Davis.
Grivetti notes that a genetic test will help differentiate between different kind of cacao varieties or hybrids, but not whether it comes from a specific farm in the highlands of Peru, for example. That will depend on the honesty of the grower and the company that is marketing the high-priced bar. Grivetti noted that high-quality chocolate is often determined by its production methods, rather than whether it came from a small, remote plantation.
“Yes you can run a genetic test,” Grivetti said. “That may be the case, but so what? Does that improve the quality or improve the flavor? No. But it may increase the price. It's another thing that buyers who want an extra special feature will pay a dollar for.”