Application Rate-Dependent Determination of Odor Activity Values (OAVs) and Key Odorants: A Case Study of Cumberland Rosemary Essential Oil

Abstract

Cumberland rosemary (Conradina verticillata Jennison) is an underused aromatic plant with potential as a flavor material. Although key odorants in the whole plant have been reported, those in its essential oil and the effect of application rate (AR) on odor activity values (OAVs) remain unexplored. Thirty-four volatiles were identified by GC–MS, 26 odorants were detected by GC–O, and 21 were quantitated for OAV calculation. Twenty-one volatiles exhibited OAVs ≥ 1 at 100% AR, compared with 15, 11, and 7 volatiles at 100, 10, and 1 ppm, respectively. Omission experiments showed that volatiles not detected by GC–O did not contribute to the aroma profile. The number of key odorants also increased with AR. At 1 ppm, key odorants included 1-octen-3-one, 1,8-cineole, and (R)-(–)-linalool. These three compounds remained important at 10 ppm, together with eugenol. At 100 ppm, all four remained key odorants, with α-pinene and camphor also becoming key contributors, bringing the total number of key odorants to six. Overall, OAVs alone could not reliably predict aroma impact without validation through recombination and omission studies.