How to make tomatoes taste awesome again — Speaking of Chemistry

How to make tomatoes taste awesome again — Speaking of Chemistry


A ripe heirloom tomato can be an epiphany–soft,
juicy, colorful, flavorful. So why are so many supermarket tomatoes tasteless
and rock hard? Thanks to science, we know why these supermarket
shams are so darn miserable. And what can be done to make supermarket tomatoes
totally terrific. So the first thing you need to know it that tomatoes go through puberty just like the rest of us. That’s what ripening is: A hormone driven
process that turns juvenile green tomatoes into mature fruits ready to spread their seeds
and get cracking on the next generation. Tomato puberty kicks off with the simple molecule
ethylene. This hormone activates enzymes that build
pigment compounds, such as red lycopene. And it activates enzymes that build flavor
molecules such as β-ionone, which gives tomatoes a pleasantly floral odor of roses and violets,
geranyl-acetone which adds leafy notes, and 6-methyl-5-hepten-2-one, which gives a citrus
kick. Teenage tomatoes also produce enzymes that
convert starch to sugar to sweeten the flesh, and enzymes that break down cellulose and
pectin to make the fruit soft and juicy. Remember, this wonderful cascade of chemistry
all begins with ethylene. Herein lies the root of the problem with supermarket
tomatoes: Long ago, the produce industry began messing with tomato puberty by breeding tomatoes
to survive long-distance shipping and still look good despite the jetlag. In the 90s, tomato breeders announced a breakthrough:
A variety that remained hard during shipping and then ripened on supermarket shelves or
in your fruit bowl. This travel hardy variety has a mutation that
curtails the production of ethylene, the ripening hormone. As a result, the biochemical drive to ripen
in mutant plants is roughly half of what you’d find in wild tomatoes. Less ethylene means harder fruit and easier
shipping, but it also means that there are fewer enzymes to produce flavor and sugar. This mutation essentially traps the popular supermarket tomato variety midway through adolescence. This is a fate I would not wish on any
life form. There’s more bad news. Decades ago tomato breeders also decided that
tomatoes should have a uniform red color— so they bred out the mottled green splotches you see in wild tomatoes and the heirlooms varieties at farmers’ markets. Unfortunately, this perfect complexion comes
from a mutation in a gene essential for churning out chloroplasts in the developing fruit. Chloroplasts are organelles in plant cells
that harness light energy to produce sugar. They are also responsible for the very many pleasurable flavor aromas found in tomatoes. That means the beautiful mutant tomatoes have
less sugar and less fragrance. Turns out that beauty does really come with a price. OK, so here’s the good news: Researchers in Florida
and China recently sequenced the genome of 398 different varieties of tomatoes—wild
varieties, heirloom tomatoes, supermarket charlatans, you name it. Using human tomato-testers, the scientists
figured out which flavor and odor chemicals customers liked. Then they tracked the 28 most prized molecules
back to the tomato genes that made them. The team found that—surprise surprise—most
supermarket varieties make half of these molecules at vastly reduced levels. The researchers also found that when supermarket
tomatoes are bred to be bigger, sweetness comes at the expense of bulk. With these discoveries, breeders now have
molecular markers to help them find a path to tastier supermarket tomatoes. Although genetic engineering could restore
all the great characteristics to tomatoes pretty much instantaneously, consumers aren’t
keen for GMO fruits. But growers can still use slower old-school
crossbreeding methods to create a tomato with more of desirable genes. As we wait for breeders to restore tomatoes to their former glory, here’s a tip for getting the most out of your red fruits. Don’t put the tomatoes in the fridge. Seriously people, science has shown that chilling
tomatoes blocks the production of flavor-making enzymes. Friends don’t let friends refrigerate tomatoes. Do you have any produce pro tips to share? Fire away in the comments.

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