Preparation and characterization of tea tree oil/ hydroxypropyl-β-cyclodextrin inclusion complex and its application to control brown rot in peach fruit

The ultrasound method was used to prepare tea tree oil/hydroxypropyl-β-cyclodextrin inclusion complexes (TTO/HP-β-CD IC). The optimal ultrasonic conditions were 120 W at 40 °C for 70 min, and the optimal ratio of core to wall was 1 : 10, resulting in an encapsulation efficiency of 80.63%. Physicochemical characterization of the IC demonstrated successful complexation of TTO/HP-β-CD and the enhanced thermal stability of TTO. Characterization was done using scanning electron microscopy, UV–Vis absorption spectroscopy, fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetry/derivative thermogravimetry and differential scanning calorimetry. The rate of sustained-release of TTO and its anti-Monilinia fructicola activity after prolonged storage were tested in vitro. TTO showed sustained released from TTO/HP-β-CD IC over the course of a month, both at 4 °C and 20 °C. TTO/HP-β-CD IC stored for 12 months inhibited the growth of M. fructicola, in vitro, as efficiently as freshly prepared IC. TTO/HP-β-CD IC has greater stability and long-lasting antifungal properties than unencapsulated TTO. TTO/HP-β-CD IC could inhibit the growth of M. fructicola in vitro test and in peach fruit.