Identification of key aroma compounds underlying three distinct aroma types of longan (Dimocarpus longan Lour.) fruit...

Longan fruit is renowned for its sweet aromatic flavor and nutrition; however, the essence of its aroma formation remains unclear. This study employed three cultivars with distinct aroma profiles-'Shixia' (SX), 'Lidongben' (LDB), and 'Xiangcui' (XC)-for sensory evaluation and volatile profiling throughout fruit development. Terpenoids and esters rapidly accumulated and dominated during fruit expansion. Integrating multivariate analysis, odor activity value (OAV) and GC-olfactometry (GC-O), this study first identified 19 characteristic aroma compounds and elucidated their biosynthetic pathways. Seven key compounds defining aroma types were distinguished: (E)-β-ocimene as a common background aroma contributed to fresh green scent of SX, linalool and methyl salicylate provided floral notes in LDB, while four ethyl esters imparted a winy aroma to XC. Molecular docking revealed spontaneous binding (-2.57 to -5.35 kcal/mol) of all key compounds to olfactory receptors. These findings clarify the chemical basis underlying aroma diversity in longan and support flavor quality improvement.