Anyone tasted a good tomato lately?

We were in Sorrento at lunch one day and decided to have bruschetta — and the color of the tomatoes were deep, glowing red, but the taste of the tomatoes was otherworldly. An Italian friend of mine told me his father had visited him here and asked what was wrong the tomatoes — he said they had no taste.

Have you had a good tomato lately?

Here’s why not:

The mass-produced tomatoes we buy at the grocery store tend to taste more like cardboard than fruit. Now researchers have discovered one reason why: a genetic mutation, common in store-bought tomatoes, that reduces the amount of sugar and other tasty compounds in the fruit.

For the last 70-odd years, tomato breeders have been selecting for fruits that are uniform in color. Consumers prefer those tomatoes over ones with splotches, and the uniformity makes it easier for producers to know when it’s time to harvest.

But the new study, published this week in Science, found that the mutation that leads to the uniform appearance of most store-bought tomatoes has an unintended consequence: It disrupts the production of a protein responsible for the fruit’s production of sugar.

Mass-produced tomato varieties carrying this genetic change are light green all over before they ripen. Tomatoes without the mutation — including heirloom and most small-farm tomatoes — have dark-green tops before they ripen. There is also a significant difference in flavor between the two types of tomatoes, but researchers had not previously known the two traits had the same root cause.

The study authors set out to pin down the genetic change that makes tomatoes lose their dark-green top. They focused their attention on two genes — GLK1 and GLK2 — both known to be crucial for harvesting energy from sunlight in plant leaves.

They found that GLK2 is active in fruit as well as leaves — but that in uniformly colored tomatoes, it is inactivated.

Adding back an active GLK2 gene to bland, commercial-style tomatoes through genetic engineering created tomatoes that had the heirloom-style dark-green hue. The darker green comes from greater numbers of structures called chloroplasts that harvest energy from sunlight.

The harvested energy is stored as starches, which are converted to sugars when the tomatoes ripen.

The vast majority — 70% to 80% — of the sugar in tomatoes travels to the fruit from the leaves of the plant. But the remaining amount of sugar is produced in the fruit. This contribution is largely wiped out in uniform, commercial-style tomatoes — and thus they won’t be as sweet.

Study coauthor Ann Powell, a biochemist at UC Davis, noted that this isn’t the only cause of the uninspiring flavor of modern mass-produced tomato varieties, but said it definitely contributes.

Though the scientists were not even able to taste their own creation because ofU.S. Department of Agricultureregulations, they could show through chemical tests that the sugar levels were 40% higher in their engineered fruit. Chemicals called carotenoids, which also significantly contribute to flavor, were more than 20% higher.

But don’t expect to find a tastier, transgenic tomato based on this finding on store shelves anytime soon. Plant biologist Jim Giovannoni of Cornell University, a study coauthor, said that such a product is unlikely to be developed.

“There are very few examples of genetically modified fresh-market fruit crops,” he said. Most such crops are corn and soy varieties that have been bred to resist viruses and pests, not fruits and vegetables sold on store shelves.

 

About Scot McKnight

Scot McKnight is a recognized authority on the New Testament, early Christianity, and the historical Jesus. McKnight, author of more than forty books, is the Professor of New Testament at Northern Seminary in Lombard, IL.

  • Anna

    Yep. If you want good tomatos, you have to shop a farmer’s market that grows heirloom varieties or grow your own.

    Brandywines are not beautiful, but oooohhhhhhhhhhhhhhhhh myyyyyy, are they just beyond wonderful when it comes to flavor…..

    If only my yard wasn’t in such deep shade.

  • Phil Miller

    Raw tomatoes are one fruit that I have never liked regardless of where they come from, so I’m probably not the right person to judge good from bad. I do like a good tomato sauce, though.

    I have heard that another reason why mass-produced tomatoes are the way they are is because they are harvested very early and ripened by ethylene gas. That in and of itself isn’t necessarily a problem since ethylene gas is actually a by-product of ripening fruit. But if they’re picked too early, they’ll never get that sweet.

  • http://LostCodex.com DRT

    I live in the home of Hanover tomatos, they are famous.

    My plants have not started to ripen yet, but there is a grower near me that started selling them this week and they are very very good. People around here grow many plants and then can them for the winter too.

    The supermarket kinds are all terrible. I have never bought one there that is good, all tasteless.

  • http://theparsonspatch.com Mark Stevens

    Supermarket tomatoes are bred too look good, keep well and package well. As Anna said, heirloom are the way to go. They also provide a vast amount of varieties and even colours! But they key is to plant them and grow them organically! Chemical fungicides and herbicides also detract from the flavour.

    We grow heirloom and have never looked back. The yields are amazing!

    Scot their is a book entitled “All About Tomatoes” by Clive Blazey. He is an Australian author. He explains a lot of the background to the article you quote. You can buy it here http://www.diggers.com.au/all-about-tomatoes.aspx

  • http://www.glimpseofgreen.blogspot.com Kelly

    Even more alarming than the poor quality of our tomatoes is the fact that FL’s tomato fields, where 90% of our domestic product comes from, are considered “ground zero” for modern day slavery. IJM just started a campaign to combat this, if anyone would like to check it out and petition their supermarkets to join the Fair Food program.
    http://www.ijm.org/files/recipe-for-change/Recipe-for-Change-Fact-Sheet.pdf

    https://secure3.convio.net/ijm/site/Advocacy?cmd=display&page=UserAction&id=151&utm_source=Bitly&utm_medium=Social&utm_campaign=R4CAction

  • Holly

    Why yes, every summer, every year! :) Grow your own…and save the seeds for next year. Circumvent uniformity….grow a little basil too and along with french bread and a little mozarella – WOW! :) I hate buying tomatoes.

  • James Petticrew

    Currently on the tiny island of Gozo in the Med, local tomatoes drip with flavour, very pleasant change from supermarket bought varieties. I have also noticed that my eyes water when cutting onions here that never happens with supermarket bought ones back in Scotland.

  • http://LostCodex.com DRT

    I had some leftover ricotta that I used for me salmon on the 4th of July meal, threw it on a bun with a big thick slice of local tomato…..and I am still feeling happy! Good combo.

  • derek

    One of my summer jobs during college was conducting research on tomatoes. These were the thick skinned variety that were harvested by machine. You could bounce them on the ground when they were red! Most of your store bought ketchup and pasta sauce are made with these.

  • Brian Cool

    Mass produced tomatoes have been engineered to also withstand the impact of falling from the conveyor belt to wagon while being harvested. At impact to the bottom of an empty wagon, a tomato reaches a speed of 13 miles per hour. Hence the nickname of gen-mod tomatoes – “the 13 mile an hour tomato”. (I can hear my friend’s saying now “thanks Cliffy” – as in Cliff Claven from Cheers)

  • http://www.sustainabletraditions.com Jason Fowler

    heirlooms are best :)

  • http://www.grizmo.biz David Reeves

    Cherokee Purple, an heirloom variety, exceptional taste and really cool looking purple tomato.

  • http://theparsonspatch.com Mark Stevens

    Wow, I am really encouraged by how many people grow their own and grow heirloom varieties!!!

  • me

    I haven’t had a good tomato since last summer, and yes, I too grow my own, plus belong to a CSA. I just don’t eat or buy commercial tomatoes. They are terrible and I’m trying to eat food when it’s in season.

  • http://eatingasapathtoyoga.wordpress.com Guiltless

    We grow our own, have been doing so organically since the 1970s. There is a definite difference in taste between ours, and store-bought, and especially those served in restaurant.

  • http://LostCodex.com DRT

    Folks, I made burgers (on charcoal) as two very thin patties with cheese on the inside then sealed around, on buns with big thick slices of the good tomatoes, and they are heavenly. The best burgers I ever had. (also put finely chopped onions in the meat) Yes, ummmm, cheese in the middle before grilling…ummmmm.


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