Ultrasound-mediated molecular self-assemble of thymol with 2-hydroxypropyl-β-cyclodextrin for fruit preservation

In this study, the inclusion complex (IC) of thymol with 2-hydroxypropyl-β-cyclodextrin (HPβCD) was fast synthetized by ultrasonic technology and its antifungal activities were evaluated. The thymol/HPβCD-IC was characterized by UV-vis absorption spectroscopy, fluorescence emission spectroscopy, powder X-ray diffraction, FT-IR, ¹H-NMR, TGA and DSC. The phase solubility studies proved that the aqueous solubility of thymol was significantly improved by forming the inclusion complex with HPβCD, and the thermal stability analysis showed that thymol/HPβCD-IC had a better thermal stability than pure thymol. The in vitro antifungal activities of thymol/HPβCD-IC against Botrytis cinerea, Penicillium digitatum and Alternaria alternata were significantly improved compared with pure thymol. Furthermore, the gray mold rot of tomatoes was evidently inhibited by thymol/HPβCD-IC treatment in vivo study. Therefore, the complexation with HPβCD assisted by ultrasound is a promising approach to solubilize and stabilize thymol for application as an antifungal agent in fruit preservation.