Antioxidant and antimicrobial efficacy of microencapsulated mustard essential oil against Escherichia coli and Salmonella Enteritidis in mayonnaise

Abstract

The aim of this study was to investigate the effect of pure and encapsulated mustard essential oil (MEO) on the shelf life of mayonnaise and its ability to be an alternative for synthetic preservatives. Determination of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) indicated higher sensitivity of Escherichia coli O157:H7 (E. coli O157:H7) (MIC: 512 ppm, MBC: 1024 ppm) than Salmonella Enteritidis (S. enteritidis) (MIC: 1024 ppm, MBC: 2048 ppm) to MEO. Mayonnaise samples, were subsequently prepared according to the determined MIC and MBC of MEO for microbial analysis and physicochemical analysis. The antimicrobial activity of MEO in mayonnaise over 40-day storage indicated that the application of free and encapsulated MEO could inhibit the growth of target bacteria. In addition, the oxidative stability of mayonnaise samples exhibited decreasing trends over the storage time. At the end of the storage, the control sample without any preservatives revealed the highest peroxide value (3.59 meq O₂ /kg of oil) whereas the sample containing 4096 ppm encapsulated MEO (2 meq O₂/kg of oil) exhibited better oxidative stability, following t-butyl-hydroxyquinone (TBHQ) (1.84 meq O₂ /kg of oil) as commercial antioxidant. Interestingly, the application of 2048 and 4096 ppm encapsulated essential oil had no undesirable effect on overall acceptance of mayonnaise, while the application of pure MEO at the same concentrations negatively affected the color, odor, taste and overall acceptability.

Keywords: Antibacterial; Antioxidant; Encapsulation; Escherichia coli; Mustard essential oil; Salmonella Enteritidis; Sensory attributes.