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The influence of high pressure processing (HPP) and polysaccharides on the structure and emulsifying properties of lactoferrin (LF) has been investigated by fluorescence, circular dichroism, FTIR, dynamic light scattering, physical stability, confocal laser scanning microscopy, and microrheology measurements. Compared with LF alone, the presence of xanthan gum (XG) inhibited the exposure of hydrophobic core in LF caused by HPP to a certain extent. HPP slightly changed the secondary structure of LF, while the addition of XG expanded the effect. 200 MPa treatment was favorable for LF-XG complexes to form ordered structure, while higher pressure decreased the content of α-helix. HPP treatment or XG addition both led LF molecules to unfold, while the combination of them caused LF to fold under certain conditions. Droplet sizes of LF-XG stabilized emulsions were smallest under 400 MPa. HPP increased the charges on the surface of droplets. HPP caused the oil droplets closer to spherical, more evenly distributed and reduced the flocculation among droplets. The Addition of 0.3 wt% XG or combination of 0.2 wt% XG and HPP could maximize the physical stability of emulsions. By altering the molecular structure of LF or LF-XG, HPP, and XG increased the viscoelasticity of emulsions. [ABSTRACT FROM AUTHOR]

Interfacial protein–polysaccharide complexes can be utilized in emulsion-based delivery system and contained functional component or medical ingredient. In the present work, the interaction of lactoferrin (LF, 0.2 wt%) with beet pectin (BP, 0–0.15 wt%) was researched in aqueous solutions at different pH (2–9) and ionic strength (0–800 mM) to provide the information about properties of complexes. A simulative environment was created to explore the optimal concentration of BP to formulate LF-coated stabilized emulsion and how the emulsion responded to the changing environmental pH (2–9) and ionic strength (0–500 mM). Particle size, particle distribution index, zeta-potential, turbidity, Turbiscan stability index,, and peak thickness were used to characterize the physical stability of emulsions. The confocal laser scanning microscopy was used to derive the microscopy images of droplets. The results indicated that 0.4 wt% was the optimal concentration to formulate emulsions, and the LF-BP-coated bilayer emulsion has a preferable stability in more extensive range than the pure LF-stabilized emulsions under the environmental stresses through electrostatic interactions. The results of this study will play an important role in facilitating the utilization of LF-BP complexes as an emulsifier in the development of incorporating functional component or medical ingredient into commercial products. [ABSTRACT FROM PUBLISHER]