Scientists Discover Why Most Tomatoes Taste Awful—And How To Fix It

Lack of ultraviolet light may explain why foodies hate greenhouse-grown tomatoes

A man works in a tomato's greenhouse in the Sicilian town of Comiso — (REUTERS)
Sep 21, 2016 at 3:37 PM ET

Greenhouse tomatoes are a crime against humanity. Ask any foodie — the ideal tomato is grown outdoors in the finest soil; it matures throughout the early and midsummer, just in time for harvest before winter temperatures sweep in and ruin the crop. Out-of-season tomatoes, often grown in large commercial greenhouses, are all but inedible to the sophisticated tomato-lover’s palate.

Until now, the reason why out-of-season greenhouse tomatoes taste awful eluded us. But a new study in the Journal Of Agricultural And Food Chemistry suggests that the lack of ultraviolet light in a greenhouse may be part of the problem. Researchers found that the glass walls of the greenhouse block UV light, which can cause stress in tomato plants that may alter the fruits’ ultimate flavor. And when they artificially introduced ultraviolet rays into the mix, taste testers loved the result.

“Fruits harvested from off-season, greenhouse-grown tomato plants have a poor reputation,” the authors write. “These studies represent the first reported use of…UV radiation throughout the…tomato plant life cycle to positively enhance the sensory and chemical properties of fruits.”

More GMO Denial Is A Religion, Not A Science

For the study, researchers grew tomatoes under a variety of conditions — in a conventional greenhouse (ugh), outdoors during the summer, and in a greenhouse supplemented with UV light. They then asked volunteers to rate the tomatoes based on color, aroma, sweetness, acidity, aftertaste, and texture. Never before had a tomato’s identity been subject to such scrutiny.

The clear winner? Outdoor tomatoes, of course. Outdoor tomatoes had an “overall approval” rating of 6.61 out of 9, but UV-supplemented tomatoes came in close second at 6.49. And after they crunched the numbers, the researchers found that the difference between those ratings was not statistically significant — in other words, from a numbers standpoint, tasters cannot tell the difference between UV-supplemented greenhouse tomatoes and good ol’ fashioned outdoor tomatoes.

But they still hate conventional greenhouse tomatoes — those grown without UV-supplementation garnered a dismal score of 5.67, which was quite statistically significant. So see, they’re still gross.

The findings suggest that tomato growers who are looking for a year-round solution should consider UV-light supplementation. “Pre-harvest treatments enhanced sensory perception of aroma, acidity, and overall approval,” the authors write. “Suggesting a compelling opportunity to environmentally enhance the flavor of greenhouse-grown tomatoes.” Not that it’d be hard to enhance a 5.67.