Investigating the Effect of Nanoemulsions Containing Yarrow ( Achillea millefolium ) Essential Oil on the Microbial and Oxidative Stability of Mayonnaise

This study investigated the effects of yarrow ( Achillea millefolium ) essential oil (YE) and its nanoemulsion (NEYE), at concentrations of 1% and 2%, on oxidative stability and microbial growth of mayonnaise stored for 45 days at 4°C. NEYEs were characterized with a particle size ranging from 75.5 to 152.65 nm, with a polydispersity index (PDI) of 0.7–0.91, and a zeta potential of −15.64 to −22.5 mV. The formation of NEYE was further confirmed using a scanning electron microscope (SEM). The results showed that both the free and nanoencapsulated essential oils significantly reduced the counts of Staphylococcus aureus , Escherichia coli , Salmonella enteritidis , mold, and yeast, as well as acidity, peroxide, anisidine, and Totox values of mayonnaise compared with the control sample ( p < 0.05). However, the essential oil–based nanoemulsions demonstrated greater oxidative stability and more effective microbial growth control than the free essential oil ( p < 0.05). The mayonnaise samples exhibited shear‐thinning behavior, and those containing NEYE showed a higher apparent viscosity than both the YE‐treated and control samples. The incorporation of NEYE had no adverse effect on the overall acceptability of mayonnaise, while the use of YE at the same concentrations altered color, odor, flavor, and overall acceptability. It has been revealed that essential oils can be successfully incorporated into a nanoemulsion delivery system, offering several advantages, including enhanced antioxidant and antimicrobial activity, as well as improved rheological and sensorial attributes.