Microemulsion Loaded with Laurus nobilis Oil Inhibited the Growth of Penicillium expansum and the Production of Patulin

Introduction: Penicillium expansum is one of the most common and harmful pathogens in apples and pears. Patulin produced by P. expansum is a harmful mycotoxin which threatens human and animals health. Essential oils are widely reported as an environmental friendly agent to control postharvest diseases, however, the insolubility in water and the instability limited the application of essential oil.

Purpose: To prepare a stable and soluble essential oil microemulsion, which has great antifungal activity against P. expansum and has the ability to control the production of patulin.

Methods: Microemulsion was prepared with Tween-20 as surfactant, ethanol as co-surfactant, Laurus nobilis oil as oil phase and water as aqueous phase. In vitro antifungal activity was assessed with agar diffusion method. Spore germination rate was counted with microscope. In vivo antifungal activity was determined in wounded pear. Patulin was extracted from both in vitro and in vivo culture and analyzed with HPLC followed with the AOAC Official Method.

Results: The 1000 μg/ml microemulsion completely inhibited the growth of P. expansum in vitro. The 400 μg/ml microemulsion inhibited 70.6 ± 0.02% spores germination. The 1600 μg/ml microemulsion decreased 43.2 ± 0.3% decayed incidence of pears. The content of patulin, respectively, decreased 86.4 ± 1.2 % and 97.9 ± 2.1% in vitro and in vivo when the presence of 400 μg/ml microemulsion.

Significance: This study structured a new food-grade microemulsion which has great antifungal activity against P. expansum and has the ability to inhibit the produce of patulin.