Is That a Terpenoid I Smell?

According to an analysis done several years ago by Ron Buttery, the now-retired “granddaddy” of scientists studying tomato flavors, more than 150 compounds combine to make up taste and smell in tomatoes.

Many of these chemical compounds, called terpenes, give the narrow range of smells we associate with green tomatoes. As tomatoes naturally ripen, the terpenes oxidize, becoming more aromatic terpenoids.

“That’s what makes the change from green to fruity flavors,” says Gerald Russell, a professor at UC Davis’ Food Science and Technology department.

Each terpenoid has a distinctive flavor and smell. Terpenoids also show up in various combinations in other plants. Linalool, for example, is very floral. Citral smells like an orange. Carvone, depending on the isomer, smells either like spearmint or like caraway. Phenylacetaldehyde smells like roses. All show up in tomatoes.

Betadamscenone, one of the most important compounds, has a nonspecific floral smell. But more important, Russell says, it acts as a potentiator, bringing out the smells and flavors of other compounds much like monosodium glutamate.