Many of the tomatoes eaten these days are too big, too firm and just plain dull compared with those from a half-century ago, according to new research.

In a paper published Thursday in the journal Science, a team of researchers say they analyzed the genetic code of nearly 400 varieties of tomatoes ― from the common red supermarket types to the funky heirlooms found in farmers markets. Led by Harry J. Klee, a professor of horticultural sciences at the University of Florida, the team found many of this generation’s tomatoes have lost key elements that make them taste, well, like a tomato.

To know what makes a good love apple, Klee said, you really have to understand three things that go into the vegetable’s flavor profile: sugar for sweetness, acid for the sour tang, and dozens of “volatiles,” or aroma compounds, that make up the euphoric, tomatoey scent.

“The tomato is unlike some fruits and vegetables in that there’s no one compound that I’d give you that you’d smell and say, ‘that’s tomato.’ Bananas, strawberries I could give you one compound and you’d know,” he said. “You’ve got sugars providing the sweetness, you’ve got acids counterbalancing and 25 or more volatile chemicals that are the aroma of the tomato. Without those you have no flavor, it’d just be completely bland.”