Accelerated oxidation enhances aroma quality in fresh Chi-Nan agarwood oil by sesquiterpene modulation

Chi-Nan agarwood (CNA) essential oil, valued for its pharmacological and aromatic properties, often exhibits undesirable off-odors in its raw form, which restricts its direct application. Conventional aging, typically requiring several months, is impractical for large-scale production. To overcome this limitation, the present study applied thermal treatment as a novel strategy to accelerate aging, optimize sesquiterpene composition, and enhance the oil’s overall aroma profile. The findings revealed that thermal treatment effectively removed off-odors and achieved results comparable to those of traditional aging, while markedly improving aroma quality. In contrast to conventional aging, which mainly increases sweetness, thermal treatment intensified both sweet and woody notes, resulting in a more diverse and appealing fragrance. This enhancement was attributed to the increased content of key aromatic constituents, such as 3,8-dimethyl-4-(1-methylethylidene)-2,4,6,7,8,8a-hexahydro-5(1 H)-azulenone and isodihydroagarofuran. These compounds interact with olfactory receptors (ORs) through non-covalent bonding, thereby strengthening aroma perception. Furthermore, the thermally treated oil retained nearly the same bioactivity as the fresh essential oil and demonstrated superior performance compared to the traditionally aged sample. Overall, thermal treatment represents a practical, efficient, and scalable alternative to conventional aging, offering dual advantages of enhanced aroma and preserved pharmacological efficacy. This approach holds significant promise for large-scale production and quality improvement in both the pharmaceutical and fragrance industries. • Thermal treatment is an effective menthod for off-odor elimination of fresh Chi-Nan agarwood essential oil. • Thermal treatment achieves aroma diversification by regulating sesquiterpene composition. • Enhanced aroma components boost perception via non-covalent olfactory receptor activation.