Identification of Key Aromatic Compounds in Basil ( Ocimum L.) Using Sensory Evaluation, Metabolomics and Volatilomics Analysis.

Basil ( Ocimum L.) is widely used as a flavor ingredient, however research on basil flavor is limited. In the current study, nine basil species were selected, including Ocimum basilicum L.var. pilosum (Willd.) Benth., Ocimum sanctum , Ocimum basilicum cinnamon , Ocimum gratissimum var. suave, Ocimum tashiroi , Ocimum basilicum , Ocimum americanum , Ocimum basilicum ct linalool, and Ocimum basilicum var. basilicum , and their fragrance and flavor characteristics were assessed by sensory evaluation. The results indicated that Ocimum basilicum var. basilicum and Ocimum gratissimum var. suave have a strong clove smell and exhibited a piquant taste. Metabolomics and volatilomics analyses measured 100 nonvolatile metabolites and 134 volatiles. Differential analysis showed that eugenol, γ-terpinene, germacrene D and malic acid were among the most varied metabolites in basil species. Combined with sensory evaluation results, correlation analysis revealed that β-pinene and γ-cadinene contributed to the piquant smell, while eugenol and germacrene D contributed to the clove smell, and malic acid and L-(-)-arabitol contributed to the sweet flavor in basil. This study provided comprehensive flavor chemistry profiles of basil species and could be used as a guide for basil flavor improvement. The better understanding of objective sensory attributes and chemical composition of fresh basil could introduce the improved cultivars with preponderant traits, which is also in accordance with the various demands of breeders and growers, food producers, and consumers.