Microemulsion‐based biopreservatives and γ‐irradiation as combined treatments to provide healthy and safe orange juice

Abstract

Radiosensitization of Aspergillus niger, Penicillium chrysogenum, and Saccharomyces cerevisiae was investigated in orange juice containing plant oil (lemongrass and oregano)/citrus extracts-loaded microemulsion or coarse emulsion treated with different doses of γ-irradiation. D10 value (kGy) (γ-irradiation dose required to eliminate 90% of fungal population) of targeted fungi in presence of microemulsion in compared to control and coarse emulsion was evaluated in orange juice as food model. Microemulsion resulted in 1.55, 2.33 and 2.10 times increment in relative fungal radio-sensitivity (RS) for A. niger, P. chrysogenum and S. cerevisiae, respectively, in compared to control sample without antifungal formulation. Furthermore, in situ challenge tests against pathogenic fungi were performed during 35 days of storage at 4°C. Results demonstrated synergistic antifungal activity between the plant oil/citrus extracts-loaded microemulsion and γ-irradiation (1 kGy) by enhancing the RS of fungi and completely eradicating the molds growth and yeasts in orange juice. Practical applications This study strongly evidenced that combined treatment of γ-irradiation with natural plant extracts-loaded microemulsion can be a remarkable alternative to synthetic preservatives while providing healthy, safe, and tasty foods with high added-values and consumer acceptability.