Solvent-free microwave extraction (SFME) is a clean and advanced method of extracting essential oils. In this study, it was compared to conventional hydrodistillation (HD) and steam-water distillation (SD), which are commonly used to extract essential oils from fresh ylang-ylang flowers. The yield and density of essential oils extracted via SFME within 40 min after the appearance of the first oil drop were higher than those obtained via conventional HD and SD within 3 h after the appearance of the first drop. Analysis of chemical compounds in the essential oils showed a high degree of variability in volatile compounds between the three extraction methods. Light oxygenated compounds are odor-active constituents. They comprised 81.23% of the SFME extract, whereas their levels were lower in the HD (69.94%) and SD extracts (57.98%). Total aromatic compounds were also higher in the essential oils obtained via SFME than in those obtained via HD and SD. These results support the use of SFME for ylang-ylang essential oil extraction, as it offers promising energy-/time-saving characteristics, along with higher quality.

This study examines the effects of flower storage duration and harvest time on the yield and evolution of the volatile composition of ylang-ylang (Cananga odorata forma genuina) essential oil. Oils were obtained from flowers by hydrodistillation immediately or after storage (4 h, 8 h, 24 h and 30 h) to investigate the effect of storage duration and from flowers picked at different schedules (07:00 a.m., 11:00 a.m. and 03:00 p.m.) to investigate the effect of the time of flower harvesting. The ylang-ylang oils were by analyzed by GC–MS. Storage duration had no significant effect on yield up to 8 h, whereas significant decreases occurred after 24 and 30 h. The amount of aromatic compounds decreased markedly with storage, from 73.66% in fresh petals to 57.02% after prolonged storage. Harvest time also influenced the distribution of oxygenated compounds, terpene hydrocarbons and several key volatiles. Overall, oils distilled within 0–8 h after harvest and obtained from flowers collected at 07:00 a.m. or 3:00 p.m. exhibited superior yields and chemical profiles compared with delayed distillation or midday harvest (11:00 a.m.). These results underline the importance of rapid processing and optimized harvest timing to preserve oxygenated fractions and essential-oil quality.