Preparation Of Cyclodextrin-based Sustained-release Flavor And Its Release Mechanism

In this paper,?-cyclodextrin was used as wall material and watermelon flavor was used as core material.The watermelon sustained-release flavor was prepared by aqueous solution agitation.The inclusion and releasing behaviors of watermelon flavor and ?-cyclodextrin were studied.The best preparation process of the watermelon sustained-release flavor was obtained:the mass ratio of watermelon flavor to ?-cyclodextrin was 1:3,the addition of wall material was 10%,the reaction time was 4h,and the mass ratio of emulsifier to core material was 3:1.The loading capacities of the watermelon flavor / ?-cyclodextrin inclusion complexes were9.1%.The inclusion complexes were characterized by dynamic light scattering(DLS),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The results showed that the watermelon sustained-release flavor had uniform particle size distribution and good thermal stability under the best preparation process.Gas chromatography mass spectrometry(GC-MS)and Avrami equation were used to study the individual release behavior of the seven characteristic aroma compounds in watermelon sustained-release flavor.It was found that aroma compounds could not be encapsulated in the cavity of ?-cyclodextrin at the original ratio,and the inclusion efficiency was the following trend: alcohols > aldehydes > esters.For aldehyde and ester inclusion complexes,the inclusion efficiency increased with the increase of molecular weight.On the other hand,the larger the log P value of aroma compound,the stronger the hydrophobicity,and the more slowly they release from ?-cyclodextrin.The interaction force between aroma compounds and ?-cyclodextrin was studied.From the phase solubility curves,it proved that the solubility of aroma compounds in water could be improved by ?-cyclodextrin.The phase solubility diagrams of aroma compounds and?-cyclodextrin belong to AL type,indicating the 1:1 stoichiometry of the inclusion complexes.The release rate of aroma compound/?-cyclodextrin inclusion complex was related to its stability constant.The larger the stability constant was,the slower the release rate was.The binding sites of aroma compounds with ?-cyclodextrin were studied by proton nuclear magnetic resonance spectroscopy.It was speculated that the benzene ring of cinnamaldehydeentered into the hydrophobic cavity of ?-cyclodextrin,and the six-membered ring of?-terpineol was encapsulated in the cavity of ?-cyclodextrin.