The antifungal activity of essential oils in combination with warm air flow against postharvest phytopathogenic fungi in apples

• Warm air flow enables fast and homogenous application of essential oils.
• Essential oils applied by warm air flow inhibit growth of phytopathogenic fungi.
• Low concentrations of essential oils do not influence sensory properties of apples.

Essential oils (EOs) are strong plant-derived antimicrobials. For their efficient use in the agri-food industry, the problems with technology of their application have to be solved. In vitro antifungal activity of cinnamon, oregano, lemongrass and clove essential oils (EOs) was tested by innovative method using EO in combination with warm air flow (WAF). EOs in concentrations from 0.25 to 512 μL/L of air were tested against eleven phytopathogenic fungi. Application of EOs in concentration of 4 and 16 μL/L by WAF method was used for treatment of apples inoculated with Penicillium expansum. Detailed sensory analysis of treated apples was performed. The WAF was more effective compare to standard disc volatilization method (DVM), the average minimum inhibitory concentrations in vitro were 5.6 μL/L during 5 min WAF treatment, compared to 136 μL/L during the DVM 24 h treatment. EOs applied by WAF delayed the incidence and development of P. expansum on apples with minimal adverse effect on their sensory profile. The WAF treatment could be considered for the development of antifungal treatments in the agri-food industry.