Rising living standards heighten the demand for healthier sugar-reduced foods. This study used Headspace Solid-Phase Microextraction (HS-SPME) and Gas Chromatography-Olfactometry-Mass Spectrometry (GC/O-AT) to analyze volatile components in sweet orange juice, identifying 12 key sweet aroma compounds. Sensory and electronic tongue evaluations indicated that seven sweetness-related odor substances- (E)-citral, (E)-β-farnesene, β-myrcene, tallo-ocimene, nonanal, citronellyl formate, and tallo-ocimene-significantly enhanced the sweetness of a 5 % sucrose solution. In contrast, while nonanol was found to have no sugar-reducing sweetness-enhancing effect. Furthermore, molecular docking analysis was employed to examine the regions, binding energies, and interaction forces between eight sweet and fragrant aroma compounds from sweet orange and the T1R2-T1R3 sweet taste receptor-sucrose ternary system. The average binding energies with the receptor were -3.2 kcal/mol, -1.2 kcal/mol, -3.0 kcal/mol, -1.6 kcal/mol, -5.9 kcal/mol, -5.8 kcal/mol, -3.6 kcal/mol, and -6.0 kcal/mol, respectively. However, it should be noted that binding energy alone is not the sole criterion for judging the sweetening effect. Molecular dynamics (MD) results further demonstrated that the stability of the binding between sucrose and the sweet taste receptor was improved under the influence of (E)-citral, with the interaction between the two relying on hydrogen bonds, water bridges, and hydrophobic forces. This provides a theoretical basis for validating the sweetness-enhancing effects of aroma substances and insights into novel sweetener development.
Keywords: Characteristic aroma compounds; Molecular docking; Molecular dynamics (MD) simulation; Sugar reduction and sweetness enhancement; Sweet orange; T1R2/T1R3 sweet taste receptor.
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