Researchers at the University of Florida have found an inexpensive way to extract the antioxidant lycopene from tomatoes, a technology that could turn a mountain of discarded produce into a marketable commodity.
“It's a very good solution to two problems,” said Murat Balaban, a professor of food engineering and processing at UF's Institute of Food and Agricultural Sciences. “You have a shortage of lycopene, which costs $2,500 per kilo in its pure form. And you have farmers with tons of blemished tomatoes they can't sell or even give away.”
Balaban is part of a team of six UF researchers who are investigating new lycopene extraction methods. The team is headed by Amy Simonne, an assistant professor of food safety and quality at UF.
Lycopene, the substance that gives tomatoes their characteristic red color, is also a powerful antioxidant, one of a family of chemicals that promote health by protecting cells from damage caused by oxidation. The chemical has been linked to lower rates of prostate cancer and other illnesses.
Lycopene's popularity has led a number of health food companies to incorporate the nutrient into their vitamin supplements, driving up demand for the chemical.
Pure lycopene has traditionally been extracted from tomatoes through a process using chemical solvents — but lycopene suppliers, who once sold the chemical only to scientists, are having difficulty keeping up with the new demand.
Even so, there's no shortage of raw material for the fledgling lycopene industry. Every year, packing and processing plants throw away one out of every 10 tomatoes brought in by farmers, UF and industry experts say.
With Americans consuming more than 25 billion pounds of tomatoes a year, according to U.S. Department of Agriculture statistics, those cast-off tomatoes add up to a mountain of produce. The discarded fruit typically isn't in very bad condition, but even minor cosmetic problems — such as blemishes or an odd shape — can keep a tomato from meeting USDA quality standards.
For packers, those tomatoes are worse than worthless. Packing houses must foot the bill for disposal of the tomatoes, which is governed by federal rules meant to prevent runoff of the fruit's acidic juices. With luck, a packing house can find farmers willing to take away at least some of the discards for use as cattle feed.
But Balaban and his colleagues may have solved that problem. By putting tomatoes in a supercritical gas extractor — the same kind of machine used to decaffeinate coffee beans — they can remove a few grams of expensive lycopene from a few hundred pounds of cast-off produce.
The process doesn't leave behind the chemical residues associated with other forms of lycopene extraction. Industrial-sized versions of Balaban's extractor are already used in the food industry, where they are used to obtain hops for beer production and extract medically valuable substances from various herbs.
“The industry could probably do this now with the technology they have,” Balaban said. “They just need someone to work out some of the methodology, which is what we've done.”
Balaban said other universities have also experimented with using supercritical gas to extract lycopene, but his method offers greater yield of the chemical than previous techniques. That could make a big difference in convincing the food-products industry to adopt the technique, he said.
“They'll use this if they determine they can make money with it,” Balaban said. “That's dependent on a lot of factors — the price of the chemical on the market, the cost to make it and the cost to transport it — but increasing yield can only make the process more profitable.”
The technology could open new markets for the tomato industry, said John VanSickle, a UF professor of food and resource economics. Growers tend to pick and sell their tomatoes when prices are best, leaving late-season fruit for “pinhookers” — speculators who scour fields and sell the fruit, often at roadside markets, he said.
“You could let the tomatoes ripen on the vine, which increases their lycopene content, and sell them for processing,” VanSickle said. “The fruit wouldn't have to be in perfect condition, so that opens the door to some sort of mechanical harvesting, which would cut labor costs.”
But for now, packing houses have more than enough produce to keep a fledgling lycopene-extraction industry in business.
“Any new use for these tomatoes would be of tremendous value to us,” said Jay Taylor, president of Taylor and Fulton, a packing house in Palmetto. “It's sad to see this much food going to waste, particularly when so many of these tomatoes have only minor problems.”