Comparison of key floral components between two Tilia species and among different processing technologies as revealed by widely targeted metabolomic profiling.

Background: Tilia has a long history of cultivation and holds high ornamental and economic value. The volatile aroma compounds of Tilia flowers have significant characteristics that contribute to their ornamental appeal, and affect the flavor of floral tea. Here, widely targeted metabolomic analyses were conducted to investigate the aroma active compounds in the fresh inflorescences of Tilia cordata Mill. (Tc) and Tilia miqueliana Maxim. (Tm), and in samples prepared by freeze drying, air drying, and oven drying.

Results: We identified 442 volatile organic compounds by headspace solid-phase microextraction gas chromatography-mass spectrometry. Terpenoids were the most abundant and diverse group, while heterocyclic compounds were the main contributors to the aroma profile. Notably, 46 aroma compounds were identified as primary contributors to the characteristic aroma of Tilia, including abhexon, 2-isobutyl-3-methoxypyrazine, (Z)-6-nonenal, methyl benzoate, (E)-2-hexenal, 1-hexanol, 2-thiophenemethanethiol, p-cymene, furaneol, and (Z)-4-heptenal. The concentration of volatile organic compounds was higher in Tc than in Tm, indicating a more pronounced aroma character of Tc. For both Tc and Tm, the aroma compounds were better preserved and present at higher concentrations in freeze-dried samples than in air-dried and oven-dried samples.

Conclusion: These results provide a foundation for further research on the molecular mechanisms of aroma formation in Tilia flowers and on aroma as a cue for insect pollination. Furthermore, the results provide a basis for the development and commercialization of Tilia floral teas and other related products. © 2025 Society of Chemical Industry.