Gamma radiation-assisted fabrication of bioactive-coated thyme nanoemulsion: A novel approach to improve stability, antimicrobial and antibiofilm efficacy

Abstract

Foodborne diseases have always been a threat to human health. Recently, food industries have shown great interest in developing essential oils-based nanoemulsion to suppress the virulence and biofilm formation that lead to substantial economic and health problems. Focusing this issue, we attempted a novel stable gamma irradiated bioactive coated thyme-based nanoemulsion (TCP nanoemulsion) stabilized by polyvinylpyrrolidone (PVP) using sonication technique and coated with chitosan. The impact of PVP and the irradiation dose on the formation, mean droplet diameter, zeta potential, physicochemical stability and long-term storage stability were investigated. Optimum results were obtained for 0.5 PVP% and irradiated at 2 kGy, which developed a nanoemulsion with an average droplet diameter of 13 nm and zeta potential of −48 mV. The screening of antimicrobial activity and biofilm inhibition and removal against four tested microbial strains was done. TCP exhibited antimicrobial activity against all tested strains with variable extent. Moreover, it was effective in biofilm inhibition of different strains. The percentages of biofilm removal after 10 min treatment with TCP were considerable. Hence, the TCP was promising as antibiofilm and antimicrobial agents for food industries. • Novel stable bioactive coated thyme nanoemulsions were prepared by gamma irradiation. • Gamma radiation assisted the long-term stabilization of nanoemulsions. • Instead of conventional surfactants, polyvinylpyrrolidone produce stable nanoemulsion. • Proper nanoemulsion with a diameter of 13 nm and zeta potential of −48 mV was produced. • These nanoemulsions provide a step forward to a new application of in food industry.