Identification of key aroma compounds underlying three distinct aroma types of longan (Dimocarpus longan Lour.) fruit via integrated GC–MS, GC-olfactometry, and molecular docking

Terpenoids and esters were the dominant volatiles in the mature longan fruits. • Characteristic aroma compounds were identified and validated with authentic standards. • Key compounds responsible for fresh-green, floral, and winy aromas were screened. 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.