Identification of Rotundone as a Potent Odor-Active Compound of Several Kinds of Fruits.

An investigation of the aromas of grapefruit, orange, apple, and mango revealed the presence of an odor-active compound that gave off a strong woody odor when assessed by gas chromatography-olfactometry. We isolated the compound from a high-boiling fraction of an orange essential oil, and subsequent nuclear magnetic resonance analyses of the isolated compound identified it as rotundone. Mass spectra and retention indices obtained from aroma concentrates of grapefruit, apple, and mango were identical to those of rotundone, which was therefore determined to be the common woody compound in these fruits. Sensory analyses were performed to assess the effects of rotundone on model beverages of the various fruits. It was revealed that rotundone added at even subthreshold levels to model beverages did not confer directly the woody odor, but had significant effects on the overall flavors of the beverages, helping them to better approximate the natural flavors of the fruits.