Effect of Ultra-high temperature processing on the physicochemical properties and antibacterial activity of d-limonene emulsions stabilized by β-lactoglobulin/Gum arabic bilayer membranes.

The objectives of the present work were to investigate the influence of Gum Arabic (GA) on the physicochemical properties and ultra-high temperature (UHT) processability of β-lactoglobulin(β-lg)-stabilized d-limonene emulsions. Moreover, we also wanted to evaluate the antimicrobial efficiency and mechanism of β-lg-GA bilayer d-limonene emulsions. Physicochemically stable bilayer emulsions could be formed with an optimal concentration of GA (1.00 wt%), which showed a higher tolerance to both flocculation and coalescence, as well as better protective effects on d-limonene against UHT-treatment that up to 94.32% of d-limonene was retained in emulsions. Likewise, it is also noteworthy that no obvious difference in the minimal inhibitory concentration could be found between bilayer emulsions with or without UHT processing. Moreover, the antimicrobial effects of the bilayer emulsions with UHT treatment were shown to be dose-dependent, which was evidenced from the results of scanning electron microscopy and the determination of released cell constituents. Keywords: β-lactoglobulin; gum arabic; d-limonene emulsion; physicochemical stability; UHT processability, antimicrobial efficiency.