Development of oregano essential oil nanoemulsions with considerable stability and antibacterial properties: A solution for extending the shelf life of chilled pork

This study aimed to construct oregano essential oil nanoemulsions (OEO-NEs) with soy protein isolate/tea saponin nanoparticles (STNPs) for chilled pork preservation. Initially, the OEO-NEs with different OEO concentrations (0%, 1%, 2%, 3%, and 4%) were prepared and then characterized thoroughly. The results demonstrated that the OEO-NEs showed reduced droplet size (from 235.1 to 170.8 nm), increased surface charge (from -15.30 to -27.42 mV), and enhanced physical stability (from △BS 7.06% to △BS 0.08%) with the OEO concentration increased from 0% to 4%. Moreover, hydrogen bonding, hydrophobic interactions, and electrostatic interactions were observed between OEO and STNPs at the oil-water interface. The interfacial interactions were conducive to promoting the adsorption of STNPs, reducing the interfacial tension, and forming robust interface layers. At an OEO concentration of 4%, the interfacial tension decreased to 1.03 mN/m. The OEO-NEs exhibited increased release rate and enhanced antibacterial activities as the OEO concentration increased. OEO exhibited sustained antibacterial efficacy, as it was not fully released from the nanoemulsion systems during 15-day storage period. Moreover, the results of storage experiments revealed that 4%OEO-NE was most effective at retarding the quality deterioration of chilled pork, extending its shelf-life by 6 days. Overall, the OEO-NEs fabricated herein can ensure the safety and sensory quality of chilled pork throughout storage, offering a promising solution for active preservation in the meat industry.