Fabrication of Blended Rosemary/Oregano Essential Oil Nanoemulsions: Characterization, Antimicrobial Properties, and Application in Pork Patties

In the present study, a blended essential oil nanoemulsion (BEO‐NE) of rosemary and oregano essential oils was developed using ultrasonication at the most suitable amplitude and time combination. The in vitro antimicrobial effect was assessed by calculating the minimal inhibitory concentration (MIC) of individual oils and the fractional inhibitory concentration index (FICI) of blended oils. Oregano essential oil showed better ( p < 0.05) antimicrobial potential (MIC: 0.75 to 3.5 μL/mL) compared to rosemary essential oil (MIC: 1.25 to 12.5 μL/mL). The FICI values against tested organisms ranged from 0.266 to 0.90, indicating additive or synergistic effects. Rosemary and oregano essential oils were blended in a 1:2 ratio, along with a surfactant to develop a coarse emulsion. Three different amplitudes (20%, 30%, and 40%) and sonication times (4, 8, and 12 min) were tested for BEO‐NE fabrication. The combination of 40% amplitude for 8 min was chosen as optimal based on the lowest average particle size (55.31 nm) and polydispersity index (PDI) (0.223). The impact of nanoemulsion on various physicochemical, microbiological, and sensory parameters of pork patties was studied at 4°C ± 1°C over 35 days under aerobic packaging, with samples collected every 7 days. Physicochemical parameters, including pH, peroxide values, free fatty acid content, thiobarbituric acid reactive substances (TBARS), and microbial counts, were significantly lower ( p < 0.05) in the samples treated with BEO‐NE compared to the control after storage. It was concluded that incorporating rosemary and oregano BEO‐NE effectively inhibited oxidative and microbial spoilage of pork patties, enabling them to be stored successfully for 35 days in aerobic packaging under refrigeration (4°C ± 1°C) without adverse effects.