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Jul 08 2012

Why Grocery Store Tomatoes Taste Terrible

Fresh vegetables out of a garden almost always taste better than what you get in a grocery store, but nowhere is this difference more stark than with tomatoes. Those hard, red-orange-ish, tasteless orbs at the grocery store hardly seem lie the same substance at all as those incredibly sweet, juicy ones that come out of a garden. Here’s why:

WOULD you rather have tomatoes that look good, or taste good? Most people, no doubt, would swear that they prefer taste to looks when it comes to buying fruit and vegetables. But that is not how they behave. Years of retailing experience have shown that what actually gets bought is what looks good. And, unfortunately, for tomatoes at least, that is not well correlated with taste. A uniformly red skin – the sort preferred by consumers – is associated with a “cardboardy” flavour. But until now, nobody knew why.

The answer is provided by a paper in Science, written by by Ann Powell of the University of California, Davis, and her colleagues. The reason turns out to lie deep in the genetic regulation of photosynthesis. For 70 years, tomato breeders have sought fruit that ripen evenly. For that to happen, they need to start from a state of uniform light-greenness. Older varieties of tomato, by contrast, are dark green over the part of the fruit nearest the stem.

Those decades of selective breeding have done what was required. Traditional genetics identified a gene known as u (for “uniform ripening”). This, in classic Mendelian fashion, came in two forms, a dominant and a recessive. Dominant versions of a gene always trump recessive ones, so the recessive characteristic emerges only when both of a plant’s parents contribute a recessive version of the gene to their offspring. Identifying strains with the relevant recessives, and then cross-fertilising them, is the sort of thing that plant breeder are good at. But what they did not know was exactly what sort of gene u actually is…

The gene in question was for a type of protein known as a transcription factor. Transcription factors are molecules that regulate the expression of other genes and the factor in question is one that is known, in other plants, to regulate chlorophyll distribution, and thus photosynthesis.

Since about 10% of the sugars in an old-fashioned tomato are produced by photosynthesis in the fruit itself, rather than being transported in from elsewhere, and since making those sugars also results in other flavoursome molecules derived from them, Dr Powell thinks she has found the explanation for cardboard tomatoes.

So now we know why those nasty things in the local grocery store that they call tomatoes are so inedible.

25 comments

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  1. 1
    Marcus Ranum

    “Give the people what they want!”
    Our agricultural system produces the best food you know how to ask for.

  2. 2
    abb3w

    Ed’s adding a new front to the war coverage?

  3. 3
    ragarth

    I thought store-bought tomatoes tasted worse because they’re artificially ripened.

    Shipping vine-ripened tomatoes is not easy, they’re easily bruised and have a short life span, so they’re shipped distance green, then force-ripened by putting them in a CO2 rich environment.

  4. 4
    machintelligence

    Actually, I think it is ethylene gas that is used to redden tomatoes.
    A similar thing has happened to the Red Delicious apple. It has been selected for red skin color over taste and texture.

  5. 5
    ajb47

    So when I go to my plant nursery and buy some tomato plants to grow in my back yard, am I getting good tomatoes or some version of the uniform ripening tomatoes?

  6. 6
    reverendrodney

    Cardboard tomatoes are not only bred to look uniformly ‘attractive’ but to last longer in the store. And they have all the nutritive value of iceberg lettuce. Perfect for salads at Denny’s.

  7. 7
    Modusoperandi

    ragarth “Shipping vine-ripened tomatoes is not easy, they’re easily bruised and have a short life span, so they’re shipped distance green, then force-ripened by putting them in a CO2 rich environment.”
    Yet another horror story from the world of industrial farming: millions of tomatoes in a warehouse…trapped in tiny cages…under lights that never turn off…each gasping for air.

    That’s why I only buy free range tomatoes.

  8. 8
    Pierce R. Butler

    My memory (yeah, that can be problematic, or so I vaguely recall) comes up with another version. Back in the 70s, while I was busy misspending my youth, breeders came up with a “uniformly ripening” tomato in which all the fruits on a given vine matured at the same time, and with a much tougher skin.

    Voilà! Bring in the mechanical harvesters, throw out all those messy Messicans! Growers across California and Florida adopted the new variety overnight.

    Ralph Nader (or his crew) got off one of the better insights of the day: Given that the hardshell version was specified not to bust open if dropped from chest height, they calculated the speed at which the fruit would hit the floor and revealed it had a greater impact resistance than what current federal regulations required of automobile bumpers.

  9. 9
    abb3w

    @5, ajb47:

    So when I go to my plant nursery and buy some tomato plants to grow in my back yard, am I getting good tomatoes or some version of the uniform ripening tomatoes?

    If you’re buying from a local nursery, odds are they’ll carry at least a few “heirloom” varieties that aren’t. Even a lot of big box garden centers (Lowes, Home Depot, KMart/WalMart, etc) tend to have a few “heirloom” varieties these days, that aren’t so hyperbred for commercial shipability. I’d expect an actual nursery to have more.

    The ones I’d suspect as most likely for carrying the “u” gene are the big name Burpee hybrid breeds — Big Boy, Better Boy, and Early Girl.

    In contrast, I think the most common yellow pear heirloom strain lacks it — I’ve noticed (tiny) green “shoulders” on them, and they’re really tasty. However, I’ll note that some of the store-bought yellow pear tomatoes seemed more uniform and less tasty; that might be due to ethylene ripening, but I wouldn’t try saving those seeds. Of course, yellow pear are a small-size, which isn’t so good for slicing onto a sandwich, and a bit of a challenge to make into sauce. But there are other heirlooms out there.

    If it’s an actual garden shop, you might talk to a couple of the staff about the question. They may not know… but may learn, and alter their selections and/or labeling next year.

    Of course, if you’re motivated, you can always just buy a bunch of varieties of heirloom tomatoes at a local grocery store and/or farmer’s market, taste them all, and save the seeds from whichever one you think is tastiest. Starting tomatoes yourself isn’t all that hard, as long as you have just a little well-lit space indoors.

  10. 10
    laurie

    the speed at which the fruit would hit the floor and revealed it had a greater impact resistance than what current federal regulations required of automobile bumpers.

    This is why a friend refers to most store tomatoes as “15 mph tomatoes”.

    There are lots of specialty tomato seed suppliers (Totally Tomatoes comes to mind) where you can get a huge variety of seeds, and some plants in the right season. The best tasting ones are frequently the most fragile, and the trip from the garden to the kitchen is about all they can handle.

    Tomato plants that have uniform ripening are called determinates, and ones that produce all season are called indeternimates. Determinates were developed for canning, and were around long before mechanical harvesters.

  11. 11
    Chris from Europe

    @ragarth
    Are you sure it’s CO2, not ethene?

  12. 12
    naturalcynic

    Ralph Nader (or his crew) got off one of the better insights of the day: Given that the hardshell version was specified not to bust open if dropped from chest height, they calculated the speed at which the fruit would hit the floor

    Hmmmm, the speed at which a cardboard tomato will hit the floor when dropped at chest height will be the same as a squishy heirloom dropped at the same height. which remind me of something that a guy named Galileo did at Il Torre Pendente. Only the looks of the respective tomatoes and the floor afterwards will be different.

  13. 13
    Doug Little

    Ahhh home grown tomatoes. Mine are coming along just fine. They copped a bit of a beating the morning of the 5th when a massive storm came through the Detroit area but they survived without a single causality. I’ll definitely have to make sure that I do my homework next year and get varieties that don’t possess the gene. I’ll have to look to see what I planted, I know I have some Early Girls in along with about another 4-5 varieties. I like to try and get varieties that bear fruit at different times throughout the season. Even if they do possess the gene, homegrown are still way, way better than store bought, even the vine ripened ones.

  14. 14
    Jafafa Hots

    For some reason tomatoes don’t seem to want to grow in our yard.
    But we have three kinds of cherries, navel oranges, blood oranges, Meyer lemons, pink variegated lemons, pomegranates, peaches, nectarines, figs, tons of blackberries, apples, apricots, guava, dates and a massive almond tree plus many other less-impressive edible things, so I guess I can’t complain.

    Yay California!

  15. 15
    Jafafa Hots

    Oh, and two kinds of limes. Knew I left a fruit out.

  16. 16
    escuerd

    Doug Little @ 13:

    without a single causality

    Clearly, your tomatoes couldn’t have begun to exist. Therefore, your tomatoes are God. QED

  17. 17
    escuerd

    I actually thought about emailing something on this subject to Ed, when, in a Culture Wars Radio podcast, he mentioned older relatives waxing nostalgic about how some other plant (squash?) tasted so much better in the old days.

    It sounded plausible to me just because I’ve heard so many people rave about tomatoes this way. Of course, it could well just be plain old nostalgia.

  18. 18
    Midnight Rambler

    For seeds sold for garden growing, even most types that aren’t “heirloom” varieties usually don’t have that awful store blandness, because a lot of it is just being able to ripen on the vine. Also:

    A similar thing has happened to the Red Delicious apple. It has been selected for red skin color over taste and texture.

    Every apple variety that has been contaminated with genes from Delicious apples (a prime example of lying through advertising if there ever was one) needs to be expurgated and destroyed with fire. They have a distinctive insipid flavor that tends to become dominant in crosses and it’s horrible. How people can eat them baffles me.

  19. 19
    davidb

    I always thought that ripening on the vine was a more important factor regarding the taste of tomatoes than breed, soil, and anything else.

    A contributory factor being the temperature at which it is eaten – I have a strong impression that if you eat a tomato picked from the vine straight away, when the picking has been done in the heat of the day rather than the frig or inside, then it tastes better.

    Nothing in that study really changes my mind about those factors.

    David B

  20. 20
    Chris from Europe

    By the way, do you people really eat raw, unsquashed tomatoes? Ugh.

  21. 21
    mommiest

    @5, ajb47 and @13 Doug Little:

    For information on specific varieties, try Dave’s Garden; they also list areas where specific varieties are known to grow well and give some indication of whether a variety is early, late, etc. If you really want to look into heirlooms, take a look at Baker Creek seeds. If their catalog doesn’t hook you, nothing will. I seed about 30 varieties each year, testing 10 to 20. Some perform inconsistently year to year. Cherokee Purple is always solid. You can save seeds from heirlooms, including those bought at farmers’ markets, but make sure they haven’t crossed with another variety.

  22. 22
    martinc

    An example of NON-natural selection. Select for looks, and the flavour disappears, regardless of the actual mechanism behind it. I noticed this in strawberries. Strawberries these days are bigger, redder and more succulent-looking than ever before – and they taste like water. My brother-in-law who is a vegan greenie who grows all sorts of organic fruit and veg in his backyard offered me a strawberry from his yard. It was only the size of a quarter, but it tasted superb! I immediately asked for another one, and he went out and got me one … best strawberries I had ever tasted.

    Then he showed me the little window-box he was growing them in … turned out I had eaten one-third of his annual crop.

  23. 23
    JoeBuddha

    Red Delicious as a contradiction, I can accept. You can only taste the peel, AFAIR (Allergic to tree fruit, so, you know…)
    I don’t have a problem with commercial tomatoes, tho. Go figure.

  24. 24
    dingojack

    Jafafa Hots – could be the soil’s too acid for tomatoes. Try growing them in raised beds with lime added to reduce the pH.
    Dingo
    —–
    PS: On second thoughts – don’t listen to me on tomatoes. Every time we grow them they begin to put on fruit, then the leaves yellow and die. Not enough NO3 do you think?

  25. 25
    Jafafa Hots

    Never keep tomatoes in the fridge. Kills the flavor. You’ll lose 3/4 of the taste of your heirloom tomatoes by refrigerating them.

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