Monday, March 19, 2012

Fixing the Broken Tomato

Tomatoes ripening on the vine. Photo courtesy: Ajith_chatie/CC BY 2.0

If you have ever grown tomatoes in your backyard, ideally from heritage seeds, harvesting each plump red fruit at the height of ripeness, you know there is something missing from the hothouse hybrids at the local grocery. Now scientists know exactly what makes for good tomato chemistry -- including some aromas that give the perception of sweetness independent of sugars.

Moreover, they have proven a novel method for predicting and testing "likability". Corresponding author Herry Klee, of the University of Florida, says: "We now know exactly what we need to do to fix the broken tomato".

Traditional food chemists have not succeeded at analyzing the chemicals in a food like a tomato, and predicting from that "chemical recipe" which tomatoes people will like the most. Even focusing on the volatile chemicals above odor thresholds -- that's the molecules that are released into the air in sufficient quantities that their smell affects what you taste -- has not resulted in accurate descriptions of tasty tomatoes.

The scientists behind the study of The Chemical Interactions Underlying Tomato Flavor Preferences started more traditionally. They grew 152 heirloom tomato varieties, assembling 278 chemical profiles from samples of their harvest. Most of the tomato varieties were bred before the tasteless commercial tomatoes that curse modern BLTs were invented.

They found a surprising diversity of chemicals, with variations of up to 3000 times the aromatic chemical content between cultivars (another example of the biological value lost when commercial monoculture eradicates historical biodiversity). This palette of palatables gave the researchers an opportunity to poll panelists on their "overall liking", flavor intensity, sweetness, and sourness of key varietals selected as representatives of the potential range of chemistries.

Statistical analysis of the taste test results demonstrated that "flavor intensity traces to 12 different compounds and sweetness to another 12, including 8 that were also important for overall flavor." Interestingly, some of the aromatic compounds typically abundant in the red fruits are not responsible for good taste in tomatoes; the relatively less abundant aromatics qualified in the two "tasty twelve" lists.

Additionally, the study shows that some aromatic compounds in tomatoes contribute to the perception of sweetness independently of sugar concentration.

Klee focuses on the value of the study for fixing commercial tomato flavor:
This is the first step to restoring good flavor in commercial tomatoes. Consumers care deeply about tomatoes. Their lack of flavor is a major focus of consumer dissatisfaction with modern agriculture. One could do worse than to be known as the person who helped fix flavor.
Unfortunately, it is more likely that food scientists will hijack the findings of the study to make processed foods tastier, as is done with the secret ingredients in "natural" orange juice, luring the fast food consuming public even further astray from the path of fresh fruits and vegetables that taste great and are healthy to eat.

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