By Russ Banham, Contributor
Three thousand years ago, Aztec and Mayan cultures in Mesoamerica harvested cacao tree seeds and made the world’s first dark chocolate as a beverage for ceremonial and medicinal purposes. Today, dark chocolate is enjoyed the world over, with prices dependent in part on where the cacao comes from.
In the 20th century, the bitter taste of dark chocolate made it a lesser confection than that of its sweeter cousin, milk chocolate. Market perception changed when scientists pointed to the many healthful benefits of eating dark chocolate, a source of powerful antioxidants and other organic compounds that may lower heart disease risks, enhance blood flow, and improve brain function. Sales of dark chocolate in the U.S. subsequently skyrocketed, from $1.88 billion in 2006 to $45.6 billion in 2018, and a projected $62.4 billion in 2024.
However, not all dark chocolate is alike. As health-conscious nibblers know, a higher percentage of cacao is a determinant of its medicinal properties (and bitter taste). Most dark chocolate bars are advertised as having 70 percent to 90 percent cacao (or cocoa as it is labeled following the roasting of cacao seeds).
Much like coffee, the region in which the cacao was harvested factors into its market appeal and price. Venezuela’s sustainably farmed Criollo cacao, for instance, is used in making the world’s priciest dark chocolate. The dark chocolate retails for about $90 per pound or about $19 per bar, compared to three or four dollars for a typical bar of dark chocolate at the local supermarket.
“By verifying the chemical signature of different agricultural goods, producers can be held accountable for their product statements.”
-Shannon Stitzel, Ph.D., associate professor of chemistry at Towson University
But, what if the cacao didn’t come from Venezuela? That was a question that piqued the curiosity of Shannon Stitzel, Ph.D., associate professor of chemistry at Towson University, and her undergraduate chemistry students. “I was looking for compounds [to analyze] that my students wouldn’t find boring and could readily appreciate and had just read an article on dark chocolate,” she says. “When I offered it up as a research project, they were intrigued and eager to dive in.”
Food Fraudsters Beware
One in 10 foods across all food categories is adulterated or mislabeled, with the highest risk of such frauds found in the organic cacao and sugar markets, according to ethical product research firm Ecovia Intelligence. Malefactors know they can reap high prices for low-quality dark chocolate by attesting the cacao came from a particular country, the firm stated, adding that the real origin is difficult to ascertain because of the many intermediaries through which the cacao passes before the point of sale.
The fraudsters may have a harder time pulling off the scam in the future, following Stitzel’s research that culminated in a way to identify the unique chemical makeup of dark chocolate. By comparing the chemical signatures of a particular bar of dark chocolate to different soil compositions on a country-by-country basis, its geographical provenance, and whether or not the product is “fair trade” or “organic,” can be verified.
Although it is now up to the food industry to invest in the novel methodology, the research holds importance for consumers of other agricultural products like coffee, olive oil, beef, and honey, whose stated provenance affects point-of-sale pricing.
“By verifying the chemical signature of different agricultural goods, producers can be held accountable for their product statements,” says Stitzel.
A Rose Is a Rose Except When It’s Not
Stitzel and her research team studied 132 cacao samples from five different countries—Vietnam, Mexico, Indonesia, Ecuador, and Honduras. “We used liquid chromatography to separate and identify the different compounds of dark chocolate,” Stitzel explains. “We then used a mass spectrometer to identify each compound’s unique chemical patterns or signatures.”
With high-performance liquid chromatography, a bar of solid-like dark chocolate is first turned into a liquid. The liquid solvent is then passed through a pump that pressurizes it to separate into individual components. The mass spectrometer measured the mass-to-charge ratio of the molecules of the different components to identify known compounds like caffeine, theobromine, and catechins. Each country’s cacao was found to have a unique composition of these compounds, hence their different chemical signatures.
The team did not compare the cacao samples to soil composition, as the researchers already knew where the samples were grown, having sourced the products from cacao farms in each region. For manufacturers of dark chocolate to verify the origin of cacao, another step is required: Once the chemical signature is isolated, the cacao’s chemical signatures would need to be compared to different countries’ soil composition.
Technology to the Rescue
In this capacity, artificial intelligence tools like machine learning can be leveraged to rapidly search and compare the unique elemental signatures of different geographic soil compositions. This information is available in a number of soil-related databases like the United Nations’ Harmonized World Soil Database or the World Soil Information Service Soil Profile Database.
This comparison could determine if a dark chocolate bar alleged to have been made from expensive Venezuelan Criollo cacao seeds was actually made with cheaper cacao from another country. Assuming dark chocolate makers perform this two-step process, consumers can rest assured they’re buying what they’re paying for.
“We were excited by the consumer ramifications of our work,” says Stitzel, “as we felt we were at the forefront of answering the [food] traceability question, something that is relevant across the agricultural industry.”
“We were excited by the consumer ramifications of our work, as we felt we were at the forefront of answering the [food] traceability question, something that is relevant across the agricultural industry.”
She’s referring to products like Kobe beef, Manuka honey, extra virgin olive oil, and Kona coffee where provenance rings up the cash register. The price of Kona coffee, for instance, is as high as $45 for an eight-ounce bag—real Kona coffee, that is.
In 2019, bona fide Kona coffee farmers in Hawaii’s Kailua-Kona region sued several major retail chains in a class-action lawsuit for selling products designated as Kona coffee they alleged contained few if any Kona coffee beans at all. The lawsuit points out that Hawaii produces about 1.7 million pounds of actual Kona coffee annually, yet some 20 million pounds labeled as Kona coffee are sold each year. Obviously, something is amiss.
Stitzel says her research team’s findings could be applied to determine the geographic origin of Kona coffee beans, as well as the origins of other agricultural products. Meat products advertised as “Kobe beef,” made from cattle raised in the Hyogo prefecture of Japan, can be validated, as can New Zealand’s pricey Manuka honey products and the world’s most expensive olive oil, manufactured from Koroneiki olives in Greece and retailing at $140 per ounce.
“The chemical signatures also could be used to verify the origins of wines and champagne, which has to originate in the Champagne region of France to be sold as such,” says Stitzel.
Her team was in the midst of pursuing additional research when the pandemic struck. “We were hoping to get the [soil-product] comparisons even tighter, down to a sub-region of a country and even to the actual farm, but then COVID-19 shut down the university,” she says.
A research team really can’t work in a lab on a remote basis, Stitzel continues. “We’re not sure when we’ll all physically be back in the lab, but some of the undergrads are already at work individually on their own projects. One of them is actually working on developing coffee signatures to see where the beans are from and whether or not they’re organically grown.”
Down the line, she imagines that food producers can assure customers they’re buying the real deal, by affixing an RFID tag or QR code to products. “Consumers can use their smartphones to scan the information and see the entire farm-to-store traceability of the product,” she says. “Prices could then vary based on how much they like the story.”
In other words, if the story of a $19 bar of chocolate is as good as its bitter taste, the price may well be worth the value.