Antifungal impact of volatile fractions of Peumus boldus and Lippia turbinata on Aspergillus section Flavi and residual levels of these oils in irradiated peanut

• The effects of two EO vapors on Aspergillus section Flavi and its residual levels were studied in situ.
• Boldo (≥ 3 μL/g) 100% inhibited fungal growth at all aW, while poleo showed low antifungal activity.
• The major compounds in pure EOs and in peanut extracts were not the same.
• Eucalyptol and limonene were used to quantify boldo and poleo residues in peanut samples.
• Boldo and poleo EO residues were significantly decreased at the end of the incubation period.

To investigate the antifungal properties of essential oil (EO) vapors from boldo and poleo on Aspergillus section Flavi and the residual levels of the oils in peanut, irradiated peanuts conditioned at three water activities (0.98, 0.95, 0.93) were treated with 2 and 3 μL/g of boldo and 3 and 5 μL/g of poleo. EO treatments produced the greatest impact on fungal growth parameters, followed by oil concentrations and aW levels. The three main components in peanut exposed to oil vapors were piperitone oxide, α-terpinene and eucalyptol for boldo and β-caryophyllene epoxide, limonene and piperitenone for poleo. Residues of boldo and poleo EO were significantly decreased from 24.7 to 100% and from 26.6 to 99.7% at the end of the incubation period, respectively.The application of nontoxic boldo oil as fumigant in the control of Aspergillus section Flavi may represent a potential alternative antifungal treatment, without significant residues after 35 days.