Antimicrobial activity of oregano essential oil and resveratrol emulsions co-encapsulated by sodium caseinate with polysaccharides

Plant essential oils and polyphenol are promising antimicrobial agents, though their undesirable physical stability, volatilization, and hydrophobic property followed with unfavorable antimicrobial activity limited application in foods. In this study, oregano essential oil (OEO)-resveratrol (Res) emulsions were prepared using 0.25% sodium caseinate (SC) with and without 2.0% inulin/gum Arabic (GA). Antimicrobial activity of these emulsions against Staphylococcus aureus, Saccharomyces cerevisiae, and naturally occurring microorganisms in growth media and artificially inoculated on fresh-cut cabbage were assessed. Encapsulated OEO-Res with SC-GA had better antimicrobial effect than the encapsulated OEO-Res with SC-inulin followed by OEO-Res with SC alone. Incorporation of OEO-Res encapsulated by SC-GA resulted in a maximum reduction of 3.6-log and 5.77-log CFU/mL of S. aureus and S. cerevisiae in growth media and more than 90% reduction (1.53–1.93-log CFU/mL) of target microorganisms and naturally occurring microorganisms (reduced 1.36–2.19-log CFU/mL) on fresh cut cabbage. The antimicrobial ability of OEO-Res emulsions was highly related to retention of both OEO and Res. Low storage temperature (i.e., 4 °C) facilitated the retention of both bioactive compounds and reserved antimicrobial ability of them. The present study showed a potential antimicrobial ability of encapsulated OEO-Res emulsions on fresh food products.