Identification of characteristic compounds of sweet orange oil and their sweetening effects on the sucrose solution with sweetness meter, sensory analysis, electronic tongue, and molecular dynamics simulation.

The characteristic aroma compounds of five-fold sweet orange oil were analyzed using gas chromatography-mass spectrometry combined with the odor aroma value (OAV) method. The results indicated that limonene, linalool, dodecanol, (E,E)-2,4-decadienal, (E)-citral, linalool, (E)-2-decenal, and geraniol are important contributors. The sweetening effects of key compounds on sucrose solutions were experimentally investigated. The results showed that the sweetness effects of five compounds (limonene, citronellal, geraniol, β-sinensal and β-caryophyllene) were better than those of (E)-citral, linalool and octanal. Molecular dynamics implied that the hydrogen bonding residues of the T1R2/T1R3-sucrose system were converted from LYS65, GLU302, ASP278, and SER144 to ASP278, SER144, ASP142, and ASP213 after the addition of limonene. Meanwhile, the hydrophobic interaction forces of the system are significantly enhanced. The total energy of the T1R2/T1R3-sucrose system decreased from -32.08 kcal/mol to -63.57 kcal/mol. The synergistic sweetening mechanism of characteristic aroma compounds of sweet orange oil on sucrose was revealed.