Why tomatoes taste bad, how biotech could revolutionize a 'lost' fruit—and why you may never eat one

Supermarket tomatoes have a sorry reputation for looking great but tasting...well, you know…like cardboard. It's a shame, as tomatoes are very nutritious and a better-tasting tomato would encourage people, especially children, to eat it. Short of buying only heirloom tomatoes, which is not practical for everyone, what is the future of the tomato?

A tomato's taste is heavily influenced by its genes. Conventional breeding has not been able to strike a very good balance between taste and productivity, but that’s not the end of the story. Research efforts in genetic modification could bring back flavor in tomatoes, and a research study shows that these efforts are paying off: consumers in a taste test preferred genetically engineered tomatoes over conventional and even organic heirloom tomatoes.

How the supermarket tomato lost its flavor

The demise of the tomato's flavor started about seventy years ago when growers noticed that some tomatoes turned red from green uniformly when they ripened. Back then, most tomatoes had shoulders—a raised area near the depression where the tomato attaches to the stem—that turned red slower than the rest of the tomato. The green shoulders made it difficult for farmers to tell when the tomato was ready to harvest, and shoppers did not like the look of them either.

Image via Flickr Creative Commons user visualdensity.
Shoulders can still be found in heirloom tomatoes. Image via Flickr Creative Commons user visualdensity.

Supermarket tomatoes have no shoulders and are perfectly red. Image via Flickr Creative Commons user Mr. TinDC
Supermarket tomatoes have no shoulders and are perfectly red. Image via Flickr Creative Commons user Mr. TinDC

So when the uniformly colored tomatoes randomly appeared, tomato breeders realized its potential. The effect that caused the green shoulders to disappear was due to a random genetic mutation, which was dubbed the "uniform ripening" trait. Farmers began selecting seeds from the uniformly red tomatoes and crossing them with other uniformly red tomatoes to create the visually perfect commercial tomatoes that we have today.

Because of the rudimentary understanding of genetics at that time, neither farmers nor researchers knew that the "uniform ripening" trait came with a trade off; it also disabled a gene in a tomato that regulates chlorophyll. Ann Powell, a plant scientist at the University of California, Davis, and her research group reported in a 2012 Science article that the chlorophyll concentrated in the green shoulders also increased the level of flavor-creating sugars for tomatoes. When the tomatoes’ green shoulders were bred out, so were the chlorophyll and extra sugars—and the tomato's flavor. And this mutation was ubiquitous; when Powell and her colleagues examined 25 commercial tomato varieties from all over the world, they found the uniform ripening flavor reducing mutation in all of them.

"The mutation they describe in their paper is in literally 100 percent of modern breeds sold in grocery stores today," said Harry Klee, a molecular geneticist at the University of Florida, who studies the chemistry and genetics of flavor in fruits and vegetables. "It's a really good illustration of some of the problems with modern breeding of tomatoes."

Tomato breeders didn't stop at eliminating the green shoulders. As they continued to breed for more productive tomatoes and more rugged tomatoes that could withstand rough handling and long-distance shipping, the tomato breeders compromised the tomato's flavor.

How biotchnology can help put the tomato's flavor back

Genetics could play a big role in restoring tomato flavor, and some scientists have already found success. For example, by using a combination of modern genetic engineering methods and traditional breeding. Klee's aims to introduce flavor-producing traits in a supermarket tomato without compromising the productive, robust traits that commercial growers love

After correlating people's preferences with levels of sugars and particular flavor compounds in tomatoes, Klee has a pretty good idea of what the genetic makeup of an ideal commercial tomato should look like.

“I figure that with approximately five key genes we could very significantly improve flavor,” he said. Klee and his research team have already located three genes that control the production of key flavor compounds in tomatoes.

Purple tomato rich in anthocyanins contrasted with regular tomatoes. Image via John Innes Centre
Purple tomato rich in anthocyanins contrasted with regular tomatoes. Image via John Innes Centre

Other researchers are are targeting different genes to solve the flavor conundrum. The purple tomato, genetically engineered to produce anthocyanins, a group of antioxidants also found in blueberries, is further along in development. Researchers led by Cathie Martin, a plant biologist at the John Innes Centre in Norwich, UK, inserted a gene from a snapdragon flower that enables the tomato to produce anthocyanins. Anthocyanins were found to slow down the ripening process of the tomatoes, which enables them to develop full flavor while enjoying a longer shelf life.

"Our research has identified a new target for breeders to produce tomato varieties that are fuller in flavor, and so more appealing to consumers, and more valuable commercially due to increased shelf life," has said Martin.

There are other attempts to introduce genes into tomatoes that enable them to produce flavor-enhancing compounds, such as a tomato genetically engineered to produce geraniol, a rose-smelling compound found in fruits and flowers, and a tomato genetically engineered to produce more flavonoids, another group of antioxidants, which also provide nutritional benefits. These two examples have undergone blind taste tests with untrained consumers, and in both cases, the consumers preferred the genetically engineered tomatoes over the conventional ones.

Resistance to GE tomatoes

But for all biotechnology has to offer, public anti-GMO sentiments, particularly in Europe, make it difficult for researchers to commercialize their tomatoes. Martin had to move his purple tomato research facility from the United Kingdom to Leamington, Canada, because of regulatory hurdles and public fear of GMOs in Europe.

“I can’t stress enough how enlightened the Canadian regulatory process towards these types of [genetically modified] foods is—it has truly been fantastic,” she said. “There is a fear of the unknown in the U.K. I think people here viewed genetically modified food as a new technology that wasn’t controlled enough to be able to say for certain that there were no risks associated with it."

Because of the public resistance to GE, Klee plans on avoiding biotechnology altogether when he eventually produces a commercial version of his flavor-enhanced commercial, even though he is using genetically engineered tomatoes to test and confirm his findings. The reason: to avoid potential consumer backlash and the estimated $15 million needed to obtain regulatory approval for a genetically engineered tomato. Emily Willingham commented in Forbes:

Scientists can use modern techniques to ID exactly what to change in a tomato to make it sweeter and do it. But because of widespread misinformation, fearmongering, and politics, they cannot use these faster, modern approaches to actually produce the tomato. Instead, the modern techniques can serve only as a roadmap to confirm that a tomato produced by conventional means–i.e.,  more “naturally”–is exactly the same as the tomato they could develop and obtain with the modern techniques.

Researchers like Klee and Martin could succeed in producing a flavorful, commercial tomato but with current anti-GMO sentiments, it might be a long time before the fruits of their labor reach grocery stores.

XiaoZhi Lim is a freelance journalist and former GLP editor and writer.

 

  • Wharves of Sorrow

    That’s too bad this anti GM bullshit has so much power.

  • madfiddler

    There are many varieties of tomatoes that contain anthocyanins. It was not necessary to get a gene from a snapdragon. I am not against biotech, but no need to reinvent the wheel. Brad Gates of Wild Boar Farms has been growing beautiful purple tomatoes in California for some time and the seeds are available commercially.

    It may be a tough compromise to get a tomato to produce good flavor and have a shelf life that is reasonable for the market. Tomatoes continue to ripen after they are picked and flavorful ones contain a lot of sugar, which is vulnerable to the yeast that occurs naturally everywhere. I am not really against the idea of the ‘flavor saver.’ Seems like a clever concept that would be much more difficult to duplicate using traditional breeding than tomatoes featuring anthocyanins.

    There are still plenty of tomato varieties that still feature ‘green shoulders!’ They just can’t be stocked in every store all year long. High sugar tomatoes just don’t work that way. Tomatoes are made to be a seasonal fruit, and while people can puzzle on how to us GE to produce all season ripe and flavorful tomatoes, I am happy to eat them canned (they can easily because they are highly acidic) and enjoy fresh tomatoes as a summer treat.

    I appreciate the effort to demystify GE for people who have been told its the boogieman for so long, but failing to also include innovations produced by traditional breeding (a fine art, really) and the more modern gene marker breeding makes this come off as some kind of ‘us vs. them’ issue. It shouldn’t be.

    • Are you aware of any non-transgenic tomato varieties that produce anthocyanin throughout the fruit flesh? The ones I’ve seen have purple skin, but are just like any other tomato inside.

      • madfiddler

        I have not gotten the opportunity to try blue tomatoes yet, but you have a good point. I think it is still possible to obtain health benefits from anthocyanin if it is in the skin, though. Some tomatoes do have a very dark red flesh, and there are many different chemicals which give them flavor.

      • madfiddler

        Doing a little checking, it seems the flesh has only a purple tinge and not much blue. The blue tomatillo on the other hand, sports deep purple flesh in some cases. Even a blueberry has a greenish brown flesh; I’d have to assume most anthocyanins are in the skin. An actual blue-fleshed fruit would be a true novelty.

    • rick

      “I appreciate the effort to demystify GE for people who have been told its the boogieman for so long, but failing to also include innovations produced by traditional breeding (a fine art, really) and the more modern gene marker breeding makes this come off as some kind of ‘us vs. them’ issue. It shouldn’t be.”
      Well said. I think the article did explain that the ge tomato was utilized in research as a proof of concept, not for commercial release, and that gene marker breeding would be utilized to select for genes that were demonstrated to improve taste in the ge prototype. Although the author did stray into a commentary that going the traditional breeding route, albeit aided by genetic marker tools, would be a more laborious and timeconsuming route to the same end.
      I appreciate that you acknowledge that it is difficult not to have to compromise on certain qualities in commercial varieties. When people talk about how store bought tomatoes lack flavor and texture of garden tomatoes, heirloom or otherwise, they are not comparing apples to apples. A home gardener has the luxury to select for maximum taste and appearance because the tomatoes are eaten fresh and you don’t have to worry about shelf life. However, if you had to make a living selling tomatoes, particularly if you paid wholesale for them or put a lot of investment into their production, then shelf life becomes important.
      I do can tomatoes, and enjoy them throughout the year, although I’ll buy store brand canned tomatoes when needed when my own run out. But, other than tomatoes in dishes eaten out, I probably get 70% of my tomatoes I use at home in a year from my own garden. To be quite honest, it is only economical if I grow my own and you are well stocked in canning supplies so that your marginal annual investment is minimal. At one of the farmers markets in my city, I have seen canned tomatoes go for anywhere from $4.50 to $8.00 a quart jar. I can probably can my own now for about 50 cents /qt. figuring in costs to grow the tomatoes, lids and energy for cooking, boiling water bath etc. If I had to buy the tomatoes at farmers market prices, the cost would easily rise to $4.00 / qt. or more. Also, even though my gardening is an important source of food, it represents maybe 1-2% of my annual food consumption. Even this percentage uses up 10 -20% of my free time during growing season outside my job, in planting and tending garden, canning etc. To increase production so that I got 10% of all I ate would require converting most of my small yard to garden, would consume quite a bit more of my free time and could easily add a couple hundred dollars to my water bill a year. I too encourage people to can if possible and enjoy the best of both worlds, and even if it is only a token part of your diet, you wont regret it. But there are practicalities people should be aware of if we were to base public policy and personal decisions on the premise that we don’t have to rely on commercial production or limit the commercial sector’s tools to improve flavor in commercial varieties.

  • Mike

    XiaoZhi Lim is a pro GMO spindoctor. Anyone before buying this spin watch the movies “Food Inc.” and “Seeds
    of Death” to hear the other side of this topic. GMO’s are bad OK.

    • rick

      I have seen Food Inc twice, and Seeds of Death once. I won’t completely dismiss everything, but they have more value as philosophical commentary about the state of farming than reliable understandings of agronomy and biotechnology itself and are themselves great examples of “spin”. Many of the claims I know from personal knowledge to be false or presented in a way to inflate or manufacture fears and lack context that would enable a viewer to have an understanding of how and why things are done. The logical and factual defects of many others become evident with even a modest degree of diligence to dig deeper into their claims, seeking more rounded information from direct sources. One could not without writing a novel show all the misinformation or fallacies contained in the many claims of each film.
      Even if genetic engineering were eventually abandoned, these two films, along with the likes of GMO, OMG and many others have introduced a lot of misinformation that will plague our ability to make wise agronomic decisions, or reasoned public policy and personal choices for years to come. They empower people like the Health Ranger and Mercola who’ll gladly capitalize on your fears to sell you some snake oil. I’ll glady watch them, and I did, but I don’t concede that they are entitled to me suspending my judgement and buying every claim without question. I find neither particularly objective nor authoritative.

      • Mike

        That is a lot of words to say nothing Rick. what parts are misinformation? Your comment has no information about anything it’s just a vague take my word for it rant.

        • Rickinreallife

          Yeah, yeah.

    • Sterling Ericsson

      Here is a debunking of every single point made in Seeds of Death, along with references.

      http://rationalwiki.org/wiki/Seeds_of_Death

      • Mike

        Our purpose here at RationalWiki includes:

        Analyzing and refuting pseudoscience and the anti-science movement. ——-

        No slant there. How original using wiki in your name and having page look just like the real wikipedia

        • Sterling Ericsson

          The slant of being pro-science?

        • Jeff

          …Yet you couldn’t refute a single point.

          • Eric Bjerregaard

            Yet the source refuted the bunk and you simply attacked the the source instead of trying to show error.

    • Jeff

      How about you spend several years studying and performing research in biology and biotechnology at an accredited university and then the adults will give you a place at the table.

  • Jeremy Rawley

    Then we need to make European countries accept GE crops. Their scientific bodies certainly do; why can’t the public at large? Why don’t politicians understand this stuff?

    Things like this are why we need scientists in office.

    • hyperzombie

      I think that in the next few years once the patents come off GMOs, Europe will wake up one spring morning surrounded by GMOs, then they will have to approve them.

  • Why would you have to buy heirloom tomatoes to get one with flavor? Try going to a farm market where the tomatoes are picked when they’re red, instead of when they’re green. Our farm market also sold a ton of tomatoes and that was our “secret.” Tomatoes need to ripen on the plant to get the flavor.

  • Ryan Costa

    heir loom tomatoes are easy to grow, and easy to can.

  • Otisfarted

    I am a local and community farmer in the USA. I have naturally come across a purple breed this year. Flavor is awesome. It is natural. I am creating a field all for itself to workout the genetics it may need when it finally stops snowing and freezing. A scientist by trade, there is no need to rush to the lab to put something in ourselves that Mother Nature did not allow to happen. I am not godly either. Just informed.

    • Jeff

      I appreciate what you and farmers like you do for us, but read about Earth’s mass extinction events, especially the Permian. If Nature were to be personified as a mother, she’s as much Casey Anthony as she is Gaia. Naturalistic fallacy isn’t a good reason to hold back technology.

  • Eric Bjerregaard

    Nice article. I will share in Linkedin Sustainable Agriculture group. they will hate this.

  • whoisoutthere

    Nothing wrong with good old tomatoes grown on the vine w/o some “genetic breakthrough” that isn’t necessary. We get them from our farmers market, in season, and they are anything but tasteless… they are delicious. We also grow them at home. Why would GE even be necessary, we have good tomatoes. Do I need them in January, from Mexico, bought at the supermarket? Nope.

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