Chocolate may become even more delicious soon, now that the DNA of cocoa beans has been mapped. Researchers believe they have already uncovered which parts of the plant's genetic code are responsible for taste and yield. This could lead to the development of a cheaper, better-tasting chocolate.
Cocoa beans grow in varieties featuring red, orange, yellow, green or purple pods. The best-tasting chocolate comes from green-podded specimens, while coca trees with red pods produce the most chocolate. Attempts to cross the two varieties have met with disappointing results.
The Costa Rican Matina and Amelonado varieties of cocoa tree, having green pods, produce some of the best-tasting chocolate, while the red-podded CCN 51 is among the most commonly-used for chocolate production because it is bountiful.
"Because of its high yield and disease resistance, the most ubiquitous clone in large cacao plantations in Latin America is CCN 51. Unfortunately, it has a rather undesirable flavor profile because of its high acidity and astringency, and also because it lacks desirable floral aromas," the researchers said in their article.
Juan Motamayor, lead author of the study and his colleagues tracked the trigger for pod coloration to a single letter of the genetic code. They did this by comparing genetic markers in the cocoa bean to the known functions of code in other plants. Cocoa trees have around 28,000 genes to code proteins, compared to 23,000 in humans.
Previous efforts to breed forms of cocoa that would both taste great and grow quickly had to wait for the plant to reach maturity before the beans could be sampled. Now that the genetic marker for the tasty green variety is known, a new cross-breed can be "tasted" long before it reaches maturity, saving both time and money.
The genetic sequence of the Criollo variety of cocoa was completed in 2011, but the code of that type of tree has significant differences from that of a typical cocoa tree, and the length of its genetic code is significantly shorter than the more popular varieties.
Motamayor works for Mars, a food preparation corporation noted for producing Mars bars, M&M's and Bounty brand paper towels. The study was conducted by Mars Incorporated in association with the U.S. Department of Agriculture, IBM and various universities.
Cocoa in grown in 50 countries around the world by 6.5 million farmers.
The research was published in the open-access journal Genome Biology.
