UF plant researchers are putting the taste back in tomatoes By Barry Estrabook
In early 2010, I enjoyed a supermarket experience that I’d never had before. I bought a pretty, stridently red winter tomato that actually tasted like something.
As is de rigueur with so-called premium produce nowadays, my purchase bore a little sticker with the trademarked name Tasti-Lee. A few days later, I returned to the same store hoping to replenish my tomato larder, but the Tasti-Lees had all been sold. And I was left to ask, what made this tomato so different? How come I had never heard of it? Why don’t all supermarket tomatoes taste like it did? And where could I get more?
With those questions on my mind, I drove to the University of Florida’s Gulf Coast Research and Education Center southeast of Tampa. There I met John Warner Scott, a professor of horticultural sciences. Scott, who is known far and wide in the tomato business as “Jay,” is one of the most prolific breeders of new tomatoes in the state. Over his three-decade career at the university he has developed more than 30 varieties.
Each year, Scott grows several hundred different varieties of tomatoes, called “parent lines,” in test plots surrounding the Gulf Coast center. His goal is to find plants with complementary traits – one may have disease resistance but low yields, another high yields but weak immunity – and crossbreed them hoping that some of the offspring will carry the best traits of both parents.
Toiling in the hot sun, Scott pulled a floppy sun hat over his close-cropped graying hair and plodded through the rows, notebook in hand, carefully examining each plant and ticking off a mental checklist: How many fruits has it set? Are they big? Do they have cracks? Are their bottoms smooth and rounded, or do they still have scar tissue where the blossoms fell off? What’s the color like?
“With some of them, you can just look at the plant and just throw it out,” he says.
If a plant passed visual muster, Scott took out his pocket knife and, still standing in the field, lopped off a slice and tasted it.
“Plant breeding is a matter of seeing what’s good,” he says. “But you can’t make any decisions based on one season. You have to grow a variety a lot of times in a lot of environments to see if it’s really good.”
Tasti-Lee is not perfect. Its fruits are smaller than commercial growers like. But it is as close as Scott has ever come to finding a fruit thick-skinned enough to shrug off the insults of modern agribusiness, but still tender at heart and tasting like a tomato should.
Developing a better tomato can take years and even then there is no guarantee that it will be picked up by professional growers and have a shot at commercial acceptance. Florida’s multimillion-dollar tomato industry is littered with once promising but now forgotten varieties.
But in early 2010, after more than a decade of painstaking growing, breeding and crossbreeding, Tasti-Lee left the rarefied confines of academic test plots and rigorously monitored consumer tasting panels to try to make its way in the competitive hurly-burly of the produce section.
Like many plant varieties, Tasti-Lee owes its existence to a combination of serendipity and the time-sharpened instincts of a great plant breeder. In Florida, the summer of 1998 was a terrible season for anyone trying to grow a tasty tomato. For some unknown reason – too wet, too cloudy, too hot – Scott’s tomato field tests failed to produce fruits with any sweetness. Even tried-and-true varieties that had been sweet during previous years tasted dull. But one morning after tasting 50 varieties, each more bland than the other, Scott spotted a nice-looking tomato called Florida 7907. He picked a fruit, cut off a wedge and popped it into his mouth. “Aha!” he said.
It was sweet, but Florida 7907 had one big flaw that made the variety a non-starter for commercial production: It was too spherical. Florida growers like their fruits to have defined shoulders and slightly flattened bottoms. And that’s only one item on a list of must-haves. Because producers are paid strictly by the pound, plants first and foremost must produce high yields of large, uniform fruit. They have to be able to resist diseases and tolerate extremes of heat and cold. And their tomatoes need to have a long shelf life. Taste enters the equation, if it enters at all, only after all of those conditions are met.
“Sometimes I wonder why we even bother with flavor,” says Scott. “There is no easy way to breed for taste.”
Scott was also developing a line of what he calls “ultrafirm” tomatoes during the same season he happened on the sweet-flavored 7907. Among those he was developing was a tomato called Florida 8059. It was hard and had the right shape.
Sensing a match made in heaven, Scott crossbred the sweet but too-spherical 7907 with the firmer 8059 and in the fall of 2002 the first of what was then referred to as Florida 8153 ripened. Scott thought the new hybrid carried the best traits of both parents.
At trials conducted by the university, consumers on test panels agreed. Time after time, 8153 beat out other tomatoes. Subsequent chemical analyses showed that the fruit had a desirable balance of sugars, acids and volatiles. It also had a surprise bonus: Both of its parents possessed what plant breeders call the “crimson” gene. The crimson gene gives 8153 a striking fire-engine red color and an extraordinarily high level of lycopene, a sought-after antioxidant.
Florida 8153 had everything going for it, except for a catchy, appetizing name. Scott christened and trademarked his new baby Tasti-Lee, Lee being the first name of his mother-in-law, a tomato lover who had encouraged and supported his research through the years.
Four seed companies lined up to bid for rights from the university to produce and distribute Tasti-Lee seeds. The winner was Bejo Seeds, Inc. A large, family-owned Dutch firm with offices around the world, Bejo’s specialties are cabbage, carrots and other cool-weather crops.
“We felt that marketing would be a key to Tasti-Lee’s success,” says Scott. “It seemed like Bejo would be hungry to get into the tomato market and that they would push Tasti-Lee pretty hard.”
The job of giving Tasti-Lee that push fell to Greg Styers, Bejo’s sales and product development manager for the southeastern United States.
Styers, who was looking for a grower who shared his vision that Tasti-Lee was “born to be a premium tomato,” approached Whitworth Farms, which grows vegetables on seven hundred acres near Boca Raton, making it a small player in the Florida tomato business.
“Whitworth was big enough to deal with some large retailers, but small enough that they were willing to take a chance on Tasti-Lee. It was a perfect fit for us,” says Styers.
One of Whitworth’s customers was Whole Foods Market. In February 2010, Tasti-Lees began appearing in 16 Whole Foods stores in Florida. Within two years, major chains across the country were stocking Scott’s new variety, which was being grown on farms as far afield as Ohio and California.
“We went into Tasti-Lee because we wanted to change the tomato market,” Styers says. “I think the stars really lined up for Jay when he developed this variety. It truly is remarkable.”
Lost Genes Found
In the race to build a better tomato, Scott faces stiff collegial competition from Harry Klee, a fellow University of Florida professor who works out of a laboratory in Gainesville. Although the goal is the same – a tomato that can be grown commercially in Florida and come out with taste intact – the two researchers are taking diametrically opposite routes to get there.
Instead of focusing on the types of tomatoes that have dominated the market – ones favored by growers and shippers, who want toughness, disease resistance and bulk – Klee started with consumers, who are crying for decent-tasting fruit.
“We have two goals,” he told me. “One is to define what a good-tasting tomato is and two is to find the genes that control the processes that make good taste and breed them back into tomatoes. To do that, we are bringing together molecular biology and psychology.”
In his efforts to build a better tomato, Klee has joined forces with a multidisciplinary team that includes psychologists, food scientists, statisticians and molecular biologists.
“It is a very achievable goal,” says Klee, a professor in the horticultural sciences department who was recently elected to the National Academy of Sciences. “I’ll predict that within five to 10 years, you’ll see significant improvements in the flavors of industrial tomatoes. The seed companies have finally woken up and realized that there is a big problem with lack of flavor and that people are willing to pay for better-tasting tomatoes. They see that there is money to be made there.”
Much like Scott, Klee uses traditional breeding techniques of cross-pollinating plants and sorting through thousands of their offspring, hoping to find one that has the traits they seek.
Klee is convinced that tomato breeders took a wrong turn 50 years ago.
“If you ask commercial seed companies why they are making tomato varieties that have lost all their flavor, the answer is very simple,” he explains. “They have focused all their energies on their customers. Who are their customers? The commercial growers. What does a grower get paid for? Yield, size and appearance. They make more money for very large tomatoes than they do for small ones. The grower is not paid for flavor. So you have a fundamental disconnect between what growers want and what consumers expect.”
Neglected for a half century, the genes that once gave commercial tomatoes taste have become lost. To rediscover those genes, tasting panels are working their way through 150 varieties of non-hybrid heirloom tomatoes – survivors from a time when taste mattered to growers.
“Tomato flavor is really complicated,” Klee explained, “and because of that complexity not much science had been done on it until we started 10 years ago.”
A combination of sugars, acids and volatiles (the technical name for chemicals we can smell, often at minute levels measured in a few parts per billion) determines the tomato taste. Having the right balance of sugar and acids provides a foundation on which tomato taste can be built. But since most of what we perceive as flavor is actually aroma, it is the 15 or 20 volatile compounds that have the biggest impact on tomato taste. They have names that you are not likely to find on the menu of your favorite restaurant: cis-3-hexenal, beta-ionone, beta-damascenone, I-penten3-one, 2+3 methylbutanal, 2-isobutylthiazole, I-nitro-2, methyl salicylate and phenylacetaldehyde. Of those, perhaps a half-dozen are critical. Without them, a tomato will not taste like a tomato.
“You’ve got all these different compounds that are all synthesized by different chemicals independent of each other, so you have a huge scientific problem to solve,” Klee says. “We’ve identified 50 genes that affect flavor.”
Klee took the cap off a vial containing a clear liquid and waved it under my nose. I got a dizzying snootful of Juicy Fruit gum.
“You’re smelling beta-ionone,” he says, passing me another vial.
I sniffed again. There was no mistaking the summery fragrance of roses.
“That is 2-phenylethanol and it is actually a major component of rose scent,” he says.
The next vial brought my nose profound memories of fresh-cut grass after spring’s first mowing. Klee says it was cis3-hexenol.
A vial containing beta-damascenone had woodsy and fruit-flavored notes that I associated with grapes and wine.
Juicy Fruit, roses, cut grass, grapes – none of these volatiles smelled anything remotely like a tomato, yet Klee believes that all of them have to be present to deliver the fruit’s signature flavor.
Klee explains, “You need the whole package. If you bit into a tomato that was really high in 2-phenylethanol, you’d say, ‘That tastes like a rose.’ There is no one chemical that you’d smell and say, ‘Oh, tomato.’ It’s a combination of all of them.”
The taste panels are part of Klee’s attempt to identify which volatiles in what concentrations make a tomato taste good. The small heirloom called Cherry Roma – the epitome of the tomato’s dance between sweetness and tartness – has consistently won top marks. Larger varieties such as Bloody Butcher and Brandywine, much beloved by home gardeners, have also scored well.
Once the test panels had identified about 20 varieties that consistently scored highly, he chopped those tomatoes up and placed his scientific salsa in a machine called a “gas chromatograph” – in essence, an artificial nose – to “sniff” out volatiles in the choice breeds.
In consultation with Howard Moskowitz, a renowned food scientist who has worked with major companies like Pepsi, Campbell’s Soup and General Mills, UF researchers devised a computer model to provide scientific underpinning to the preferences of the hundreds of participants in taste panels.
Klee unfolded a printout that looked like an electrocardiogram, with wavy lines running across the page. One axis of the graph listed chemicals; the other a single tomato variety. The lines represented the content of each chemical in the tomatoes. Klee jabbed his pen at a peak.
“This is beta-ionone,” he says. “We’re finding that tomatoes that rate highly overall always have high concentrations of beta-ionone.”
Using his elaborate statistical tools, Moskowitz will be able to create a “formula” for a good tomato, telling Klee the concentrations of volatiles and other chemicals he should aim for.
“What we end up with is a blueprint,” Klee says. “Then we have to figure out how to reproduce that blueprint.”
That involves searching for the specific genes that cause tomatoes to produce beta-ionone and each of the other desirable chemicals. That search is rooted in a greenhouse a few hundred yards from Klee’s lab, where he pampers some of the vilest-tasting tomatoes on the planet. They don’t even look like tomatoes. They’re green and as hard, small and unyielding as a pebble. But their beauty lies at the genetic level. By crossing wild-tomato relatives like these with domesticated varieties, botanists can see what genes produce what chemicals.
Klee has now discovered about half of the volatiles he thinks must be present in a good tomato. Once all of them have been found, they’ll be a tool kit that breeders can use to reintroduce tasty traits into industrial-grade fruits.
This article was originally featured in the Summer 2012 issue of Explore Magazine.