Long-term study of Citrus changshan-huyou Y.B. Chang essential oil: Chemical transformations and their impact on antibacterial efficacy

The essential oil from Citrus changshan-huyou Y.B. Chang (HYEO) contains volatile compounds with strong inhibitory effects on biofilms formed on food processing equipment. This study analyzed the compositional changes of HYEO over 9 years and evaluated its antibacterial and antibiofilm properties. HYEO showed significant antibacterial activity during the first 8 years, effectively removing mature biofilms. Gas chromatography-mass spectrometry analysis revealed that monoterpenes were the primary components, with d -limonene and γ-terpenes converting into oxygenated derivatives during storage, resulting in a more than 16-fold increase in antibacterial activity. The antibacterial strength correlated with the number of oxygenated derivatives from limonene and terpinene among the top 20 components. Significant associations were observed between antibacterial activity and the oxygenated derivatives of d -limonene and γ-terpenes. These findings suggest the need for further investigation into their synergistic effects, antibacterial mechanisms, potential applications in food processing, and the safety profiles of the main antibacterial components of HYEO.