Effect of gum arabic on the storage stability and antibacterial ability of β-lactoglobulin stabilized D-limonene emulsion

The objective of this research was to investigate the influence of gum arabic (GA) on the storage stability and antibacterial ability of beta-lactoglobulin (beta-lg) stabilized D-limonene emulsion at pH4.0 based on electrostatic layer-by-layer deposition. The storage stability of emulsions was characterized by droplet size, zeta-potential and degradation of D-limonene during the storage of 4 weeks at 4 degrees C, 25 degrees C and 55 degrees C. Results showed that GA could significantly enhance the physical stability of emulsions and protect D-limonene from oxidation even at high temperature (55 degrees C). The antimicrobial activity of bilayer emulsion was compared with pure D-limonene and single-layer emulsion by measuring the minimal inhibitory concentration against the microorganisms tested (E. coli, S. aureus, B. subtilis and S. cerevisiae) and total bacterial, Yeast & Mold account in orange juice. Determination of cell constituents released were proceeded to investigate the antibacterial mechanism of D-limonene emulsion. D-limonene and its emulsions were shown to have different antibacterial effects, which manifested as reducing or completely inhibiting the microbial growth. Bilayer emulsion was confirmed to possess slightly inferior antimicrobial efficiency by MICs comparison than single-layer emulsion, but exerted a long-lasting antimicrobial effect in orange juice during the storage.