Design of biosystems to provide healthy and safe food—part B: effect on microbial flora and sensory quality of orange juice

This study was performed to determine the antifungal activity of plant oil extracts (1% of lemongrass and oregano, 1:1) in combination with organic citrus fruit extract (BIOSECUR F440D®) with a ratio of 1:3 (W/W) against pathogenic molds (Aspergillus niger, Penicillium chrysogenum) and yeast (Saccharomyces cerevisiae). Synthetic commercial preservatives such as sodium benzoate (E211) and potassium sorbate (E202) were used as references. Antifungal formulation-loaded microemulsion was prepared by microfluidization for in situ analysis in orange juice. Antifungal formulation-loaded microemulsion (AFF-MM) led to a total inhibition of targeted fungi during the first days of storage and their populations stayed below detection limit until the end of storage (35 days). AFF-MM presented a higher antifungal activity compared to synthetic preservatives even at a concentration of 10 times lower than optimized concentration. Indeed, microemulsion increased the bioactivity and bioavailability of plant oil/citrus extracts compared to coarse emulsion by increasing the surface area of droplets induced by size decrement. Finally, the sensory analysis showed the panelists acceptance of orange juice in presence of antifungal-loaded microemulsion.