Microstructural and rheological properties of camellia oil emulsion stabilized by sodium caseinate and konjac glucomannan with different concentration of ethanol

In this study, effects of ethanol on camellia oil emulsions stabilized by sodium caseinate (CAS) and konjac glucomannan (KGM) were investigated through rheological and microstructural properties. For camellia oil emulsions stabilized by CAS (0.3 g/kg) and KGM (0.03 g/kg), the interfacial protein adsorption rate increased from 69.63 % to 82.37 % with ethanol concentration increased. Meanwhile the droplet size reduced from 2.18 μm to 1.54 μm. The alcohol-containing camellia oil emulsions exhibited significant shear-thinning and elastic behaviors. The oil droplets became smaller and more densely packed after the addition of ethanol. Confocal laser scanning and cryo-scanning electron microscopy demonstrated a uniform distribution and tightly interconnected droplet structures in the alcohol camellia oil emulsion. Compared to emulsions without ethanol, the retention rates of curcumin loaded in ethanol (0.6 g/kg) emulsions increased to 73.09% and 52.83% after ultraviolet irradiation 12 h and 24 h. Besides, the ethanol emulsions had higher radical scavenging rate. The retention rate of DPPH· for ethanol emulsion was 45.85%, which was much lower than that of emulsions without ethanol (63.27%). The study provides a novel way for constructing functional ethanol emulsions and theoretical foundation for the research and development of alcoholic beverages and foods.