Thermosensitization enhancement of A. niger, S. cerevisiae, and L. fructivorans using combination of mild heat treatment with nanoemulsion-based mediterranean formulation to fabricate wholesome orange juice

Abstract

Consumers' demand is increasing for natural, high-quality, synthetic preservative-free products that at the same time are safe and stable. We investigated thermosensitization of A. niger, S. cerevisiae, and L. fructivorans in the orange juice which contains an antimicrobial formulation-loaded nanoemulsion (AMF-NE) combined with a mild heat treatment (55 °C for 15 min). The combined treatment resulted in 1.62, 1.47, and 2.38 times increment in the relative thermosensitization (RT) over that for the control orange juice for A. niger, S. cerevisiae, and L. fructivorans, respectively, as calculated from the D-values of the inoculated microorganisms. The sonication led to a significant reduction of the particle size, polydispersity index, and viscosity of the coarse emulsion, however, zeta potential (ζ) increased for the nanoemulsion. The results demonstrated that antimicrobial activity of combined treatment enhanced the RT of the target microorganisms and were completely inactivated in orange juice. This study demonstrated a new promising alternative to replace the chemical preservatives that could help the industry to deliver the wholesome and palatable orange juice with high consumers’ acceptability.