Competitive Inclusion of Binary Flavor Mixtures in α-, β- and γ-Cyclodextrin

Abstract

The inclusion of binary liquid flavor such as phenyl ethanol/d-limonene or methyl n-hexanoate/d-limonene into α-, β- and γ-cyclodextrin was investigated. The inclusion of the target guests (phenyl ethanol and methyl n-hexanoate) was inhibited by the presence of the inhibitor, d-limonene. Three types of inhibited inclusion were observed depending on the combination between cyclodextrins and the binary liquid flavors. The inclusion fractions of the target compounds (the molar ratio of the included target guest to cyclodextrin) were correlated by the inhibited enzyme kinetic equation of Michaelis–Menten type, which commonly used to analyze the inhibition of the enzymatic reactions. At the higher concentrations of the target guest, the competitive inclusion model could correlate the inclusion fraction independent of the type of cyclodextrin. However, at a low concentration, the presence of d-limonene inhibited the inclusion of the target guests in a noncompetitive manner for α- and β-cyclodextrin and in an uncompetitive manner for γ-cyclodextrin, respectively.