Metabolomics approach for determining potential metabolites correlated with sensory attributes of Melaleuca cajuputi essential oil, a promising flavor ingredient

Melaleuca cajuputi subsp. cajuputi is one of the Australian Melaleuca species commonly found in Pulau Buru (Maluku, Indonesia). Its oil, the M. cajuputi essential oil (MCEO), has been utilized as the main flavor of the Indonesian functional food, Cajuputs Candy. However, the availability of MCEO is becoming limited. On the other hand, Indonesia has many other potential MCEO sources which can be developed as flavor ingredient. Thus, it is noteworthy to explore these new MCEO sources by studying their sensory characteristics and metabolite profiles. This study was conducted to identify potential metabolites that are correlated to sensory attributes of MCEO by using the metabolomics approach. The metabolite profiles of thirteen MCEOs from different origins were analyzed by gas chromatography-mass spectrometry while sensory analyses on Cajuputs Candy were conducted by difference-from-control and rate-all-that-apply tests. Sixty metabolites from the MCEO were annotated that includes 1,8-cineole, α-terpineol, caryophyllene, α-pinene, and γ-terpinene. Sensory analysis revealed cooling aftertaste and sweet taste as favorable attributes. Further analysis using Orthogonal Partial Least Square indicated that 1,8-cineole and γ-terpinene were correlated with cooling aftertaste, while 1,8-cineole and caryophyllene were also correlated with sweet taste. In contrast, linalool and nerolidol were associated with the feature of the most characteristic manufacturer's products which have unfavorable attributes such as floral, iodophor-like, metallic, and soapy attributes. The identification of these metabolites will be useful for the selection of MCEOs that can potentially be used as flavor.