As tomato season rolls into farmer’s markets across the United States, it's also a reminder for foodies that the tomatoes they find year-round in supermarkets just can’t compare. After all, the cardinal rule of preserving the tomato’s tangy flavor is not to chill them, which means that any tomato transported from far away (and therefor frozen) will never be as good.
While tomatoes were first cultivated in the deserts of South America’s west coast, these days it takes storing them in glacial temperatures to keep them fresh long enough to get to the supermarket. But now, researchers from the U.S. Department of Agriculture say they’ve figured out an easy, if ironic, way to keep supermarket tomatoes tasting great despite doing time in the fridge: heat them up first.
"To produce a better tasting tomato, we added a hot water pre-treatment step to the usual protocol that growers follow," lead author Jinhe Bai said in a statement. "We found that this pre-treatment step prevents flavor loss due to chilling."
Because tomatoes often have a ways to go between being harvested and reaching the supermarket shelves, farmers have to pick them while the fruit is green and unripe, Thu-Huong Ha writes for Quartz. The tomatoes are kept at a chilly 41 to 55 degrees Fahrenheit during their trip to the store, which keeps them from producing enough of the enzymes that give tomatoes their smell and flavor. But when Bai and his team let unripened tomatoes sit in a bath of hot water for a few minutes, the tomatoes produced massive amounts of the enzymes, keeping them tasty even after refrigeration.
"Our methods can easily be implemented in the current commercial system without risking fruit decay," Bai says.
Scientists have been trying to find a solution for the flavor discrepancy between home-grown and store-bought tomatoes for years. Harry Klee, a researcher at the University of Florida, has bred a type of tomato that is resistant to bruising and disease as well as having a strong, delicious flavor, Mark Schatzker writes for Slate. Bai’s technique isn’t even the only one his group has experimented with, also incubating green tomatoes with wintergreen oil and treating unripe tomatoes with a gas that might preserve them without having to resort to refrigeration. But even Bai has to admit that the very best of his refrigerated tomatoes don’t hold a candle to the fresh ones.
"Ideally, tomatoes should be picked ripe and then sold immediately, as they are at farm stands," Bai says.