Tomatoes on the brain

The tomato. A native to Central America, it has been bred over centuries to become a staple summer crop. Gardeners across the U.S. compete openly or covertly to be the first with ripe tomatoes. Ribbons and trophies are handed out in nearly every community for the best-tasting tomato. Competitive tomato growers hold dear to secret cultural practices. Some of these tricks never leave the confines of the family and are passed through generations.

So, with our reverence for tomatoes in Illinois, what’s up with all the flavorless versions at the height of tomato growing season? At the grocery store or restaurant, our sacred fruit holds little in common with the tomatoes I ate as a child and now grow at home. When the server comes to collect our plates at a restaurant, we always send back the parsley and the pale red excuse for a tomato. Who uses a tomato as a garnish, anyway?

Adults may love them, but most children must be persuaded of a tomato’s virtues, including me, admittedly. So today, why do I balk at supermarket tomatoes while craving delicious tomatoes fresh from the vine? The answer may lie more in our noses than our stomachs.

Scent has deep ties to our brains, and the nose is the key to tasting what we put in our mouths. The olfactory bulb, the organ in our nose that processes smells, has a direct connection to the amygdala (emotional) and hippocampus (memory) brain areas.

Tomatoes are full of aromatic volatiles, fragrant compounds that make their way into the olfactory bulb. Smelling a tomato’s distinct aroma compounds sends a signal to the hippocampus and amygdala, which then lights up with the memory and emotions associated with when we first experienced that taste or scent.

Last week, I craved a turkey sandwich with a fresh sliced tomato and a chocolate shake, because that’s what my mom would make on a hot summer day for lunch. (OK, the chocolate shake was an occasional treat.) Without a fresh garden tomato, summer lunches just wouldn’t be the same.

For decades, breeders have been obsessed with the ratio of sugars to acids in tomatoes. While this balance of sugar and acid makes up a significant portion of what we taste when biting into a tomato, the aroma volatiles are what lend complexity to a tomato’s flavor.

The 2012 study, “The Chemical Interactions Underlying Tomato Flavor Preference,” shows that some of the most abundant aroma volatiles in tomatoes do not contribute to consumer liking. Instead, the research identified less abundant compounds that do — particularly a volatile compound named geranial.

Tomatoes with higher levels of geranial drew the preference of taste testers. Additionally, the research found that aroma volatiles like geranial could increase perceived sweetness without increasing the sugars in the fruit.

The herb basil contains high amounts of geranial, which must be why it pairs so well with tomatoes and can be used to revive an otherwise bland-tasting tomato.

While tomato breeders continue to work on improving the flavor of grocery store tomatoes, we can still enjoy some of our old favorites from the garden. Why do we grow tomatoes? Because they help us make summer memories.

While some gardeners have their tomato secrets, the University of Illinois Extension is happy to share its knowledge. Check out our page at for tomato-growing tips.