Formulation of mint and thyme essential oils with Arabic gum and Tween to enhance their efficiency in the control of postharvest rots of peach fruit

Abstract

The peach (Prunus persica) is a fruit that is susceptible to many fungal infections following harvest, leading to significant losses. This study was aimed at evaluating the efficacy of a novel formulation prepared from mint and thyme essential oils and used to protect peaches from postharvest decay. The formulation was prepared by mixing the oils with Arabic gum as a coating material and Tween 20 as an emulsifier. The formulations were tested for their efficacy in inhibiting fungal growth in vitro and suppressing disease development on the fruit under a wide range of temperatures and under cold storage conditions. The results demonstrated the inhibition of growth of Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer following application of the formulations. Six days following application of the formulations, the reduction in growth of the three pathogens was 83.0%, 77.0% and 88.0%, respectively. The formulations succeeded in protecting peaches from postharvest rot under a wide range of temperatures (5–30°C) in vivo. In cold storage (4°C), the formulations protected peaches from the three fungal pathogens for 10 days and significantly hindered disease progress compared with the controls, Arabic gum and Tween 20, for up to 30 days. Use of oil formulations reduced the disease incidence to 25.0–30.0% and lowered disease severity to 26.6–46.7% throughout the time the peach fruit was kept in storage. The findings support the application of the essential oil formulations, Arabic gum and Tween 20 as effective, natural and edible coating materials to preserve peaches free from infections for an extended period.