Antifungal Efficacy of Mint Essential Oil Against Penicillium spp. Inoculated on Carrots

Current research aims to investigate the chemical composition, antioxidant, and in vitro and in situ antifungal activities of commercially available Mentha arvensis essential oil (mint, MEO). The identification of the volatile substances was done using Gas chromatography–Mass spectrometry (GC-MS) analysis. A total of 42 components representing 99.5% of the total oil were identified. The main compounds in the oil were menthol (37.3%), menthone (17.4%), neo-menthol (14.1%), and 1,8-cineole (4.9%). Antioxidant assays (1,1-diphenyl-2-picrylhydrazyl radical) demonstrate only weak activity for the MEO in values 195.00 ± 5.30 μg TEAC.mL-1, with 22.8 ± 1.2% free radical-scavenging inhibition. Evaluation of in vitro and in situ antifungal activities of MEO (in four concentrations: 62.5 µL/L, 125 µL/L, 250 µL/L, and 250 µL/L) against three strains of Penicillium (P.) spp. fungi strains (P. expansum, P. citrinum, P. crustosum) were assessed by disc diffusion method and vapor contact method on the carrot as model food, respectively. The suitability of carrots as a substrate for analyzes was verified by determining moisture content (MC) and water activity (aw), which showed values of 82.80 ± 2.33% and 0.959 ± 0.001, respectively. MEO exhibited promising antifungal activity against analyzed strains of test fungi as a diameter of zones of inhibition (from 2.88 ± 0.55 to 12.33 ± 1.14 mm), as well as the effectiveness of this oil was detected on the carrot model (from -5.41 ± 7.35 to 100.00 ± 0.00%). Moreover, it can be concluded that the growth inhibition of fungi strains significantly depends (P < 0.05) on the concentration of the MEO used in both procedures. Our results suggest that MEO, as a promising natural antifungal agent, can be applied in the innovative packaging of food products including carrots.