Compound composition table of Opisthopappus taihangensis hydrosol in different open states

In order to investigate the differences in aroma components between hydrosol of Opisthopappus taihangensis in different flowering states, as well as the differences in aroma components with pure dews of dried flowers of O. taihangensis in different flowering states, the present study was carried out using ultrasound-assisted water vapor distillation for the extraction of hydrosol from fresh and dried flowers of O. taihangensis in the bud stage, the first flower stage, and the full bloom stage, and analyzed using a Headspace full two-dimensional gas chromatography-four-stage rod tandem time-of-flight high-resolution mass spectrometer was used to analyze the volatile components. The key differential aroma components between different hydrosol were screened by calculating the relative aroma vitality value (ROAV) and analyzed by combining the OPLS-DA and PLS-DA models (ROAV>1, VIP>1, P O. taihangensis, including alcohols, hydrocarbons, ketones, esters, phenols, aldehydes, ethers, and other 8 major groups. Among them, 175 compounds were identified in the hydrosol extracted from the fresh flowers of O. taihangensis (OT-F), mainly consisted of alcohols, ketones, and ethers. The main volatile components were eucalyptol (9.88~35.13 mg/L) and (Z)-chrysanthemum alkyl acetate (0~28.16 mg/L). The hydrosol extracted from the dried flowers of O. taihangensis (OT-D) contained 89 compounds, mainly esters and ethers. The main volatile components were eucalyptol (0.09~24.84 mg/L) and (Z)-chrysanthemum allyl acetate (2.06~13.06 mg/L). The overall aroma profile of O. taihangensis hydrosol presented minty, herbal and woody, floral and fruity sweet and other odors. The eucalyptol in the minty aroma was the key aroma contributing component (OAVmax) and the key differentiated aroma component (ROAV>1, VIP>1, P O. taihangensis hydrosol because it was rich in more volatile components and more intense aroma. Although the drying treatment would lead to the loss of some components, it could produce more ester, citral and other special differential aroma components, which were valuable references to the extraction of the special aroma hydrosol. This study provides valuable data for the further development and utilization of O. taihangensis.