UNITED STATES (WASHINGTON POST) - We are no slouches when it comes to eating tomatoes. In 2014, the average American ate 14.2kg of the fruit, according to Agriculture Department data; tomatoes, out of the most frequently consumed fruits and vegetables, were second only to potatoes.
But we may not be so enthralled with the flavour of the fresh ones. (As it is, the majority of the tomatoes eaten are canned. For every two fresh tomatoes eaten, Americans ate three processed ones.) Many are the lamentations of the fresh tomato fan: Supermarket tomatoes are bland, too big, flat in scent and regrettable in mouthfeel. They just don't sell tomatoes like they used to.
And yet the future grocer could hawk a tastier tomato, argued a new scientific dive into the genetics of tomato flavour. Agricultural researchers at the University of Florida, partnering with Chinese, Israeli and Spanish scientists, identified several dozen tomato chemicals that were "significantly correlated with flavour intensity," as they wrote Thursday in the journal Science.
Specifically, the scientists hunted for the best of what are called volatile compounds, the smelly organic chemicals that our olfactory systems are primed to sense.
"The real excitement of food is what you smell," said the University of Florida professor Denise Tieman, the study's lead author, to the Los Angeles Times. "When you chew, these aroma compounds get into your olfactory systems and that's what really makes things taste good."
To that end, the scientists sequenced the genomes of 398 fruits: wild varieties and heirloom tomatoes, as well as modern, commercial types. They had a consumer panel evaluate the taste of 160 tomato samples, reflecting more than 100 varieties.
Based on the consumer feedback, the researchers determined that "representative modern cultivars, such as Florida 47 and Flora-Dade, are not well liked even when grown using commercial practices and harvested when fully ripe".
When comparing modern tomatoes to their heirloom cousins, the scientists identified 13 flavourful compounds reduced in the fruits commonly found on the shelf.
Another problem, too, was the loss of tomato sweetness.
The biologists highlighted a genetic variant, Lin5, associated with the production of sugar. This was a probable casualty of agriculture - a "negative correlation between fruit weight and sugar content", wrote the researchers, "is likely associated with the loss of the high-sugar alleles during domestication". As farmers bred for bigger and bigger tomatoes, in other words, they paid a price in sugar on a genetic level.
The blame for humdrum tomatoes should not rest fully on the shoulders of the modern farmer, University of Florida horticulturalist Harry Klee, a co-author of the study, said.
"The selection for big fruit and against sugar is dramatic in the modern varieties," Klee told the Smithsonian magazine. "But it goes way back to pre-Columbian days when the Native Americans were already selecting for bigger fruit with lower sugar content." (The tomato line is long. Plant scientists recently discovered fossil groundcherries, a tomato ancestor, as old as 52 million years.)
The horticultural researchers concluded that following such a genetic "road map" could restore tomatoes to their rightful flavour. Selecting tomatoes for the alternate Lin5 variant, for instance, would restore some of that lost sugar. And the scientists were confident that shoppers would not shy away from a slightly shrunken fruit, as long as it were sweeter.
"Consumers do not prefer large fruit," the authors wrote, "and are very willing to purchase minimally smaller fruit with superior taste."