Structural rheological properties of model nutritional beverage emulsions stabilized by bovine lactoferrin: Influence of pH and oil type

The objective of this study was to demonstrate the microstructure and rheological properties of model beverage emulsions containing 1% (w/w) canola oil (CO) or rice bran oil (RBO) stabilized by bovine lactoferrin (bLF) 1% (w/w) subjected to highly acidic and neutral pH conditions. The o/w emulsions were characterized using phase contrast microscopy, confocal scanning laser microscopy and image analysis and rheology. Both CO and RBO emulsions exhibited pseudo-plastic behaviour with the flow behaviour index values being less than 1. Irrespective of pH, a difference between CO and RBO emulsions with respect to median droplet size was observed (p<0.05), which might be attributed to the differences in density and viscosity of the respective dispersed phases. The differences in surface hydrophobicity and electrostatic charge of bLF between pH 2 and 7 influenced the emulsion properties. The results might have implications in formulating highly acidic/neutral nutritional beverages containing n-3 and n-6 fatty acids and lactoferrin