Refrigerators are miracle workers in the modern kitchen. They keep food cold, crisp, and fresh. Some even check your email. But refrigeration isn’t all good. When it comes to tomatoes, we’re trading a longer shelf life for flavor when we stick them in the crisper drawer.
A study, published Monday in the Proceedings of the National Academy of Sciences, used chemical analysis (and taste tests) to show that chilling tomatoes, both heirloom and hybrid varieties, below 53ºF is responsible for a dramatic loss of flavor.
A tomato’s flavor comes from a combination of sugars, acids, and volatile molecules. But once a tomato’s temperature drops below about 53ºF, genes in the tomato stop producing those volatiles. One to three days in the cold didn’t significantly reduce the level of volatiles, but much longer and flavor takes a hit. Compared to a freshly picked tomato, the researchers observed a 65 percent drop in volatiles in tomatoes that had spent eight days in a refrigerator. Even a few days at room temperature couldn’t save them.
Per the study:
Cold storage is widely used to extend shelf-life of agriculture products. For tomato, this handling results in reduced flavor quality. Our work provides major insights into the effects of chilling on consumer liking, the flavor metabolome and transcriptome, as well as DNA methylation status. Transcripts for some key volatile synthesis enzymes and the most important ripening-associated transcription factors are greatly reduced in response to chilling. These reductions are accompanied by major changes in the methylation status of promoter regions. Transient increases in DNA methylation occur during chilling. Our analysis provides insight into the molecular mechanisms of tomato fruit flavor loss caused by chilling.
Unfortunately, the tomatoes in the produce section of your local grocery store have probably already spent time in the cold. Commercially grown tomatoes are typically shipped on refrigerated trucks, especially if they’re traveling long distances.
If you want a flavorful tomato, buy them when they’re in season from a local farmer, or pick them yourself, like the study’s author, professor Harry J. Klee of the University of Florida’s Horticultural Sciences Department: