Physicochemical and functional properties of a novel xanthan gum-lysozyme nanoparticle material prepared by high pressure homogenization

Abstract

The electrostatic self-assembly between protein and polysaccharide is a widely used method to fabricate biopolymer nanoparticles (NPs). In the present study, a novel NPs material was prepared by the high pressure homogenization (HPH) electrostatic self-assembly complexes of xanthan gum and lysozyme using the same charge at pH 12. Dynamic light scattering studies showed that the HPH treatment (30 MPa, 5 min) resulted in a smaller particle size and larger surface charge. Cryo-scanning electron microscopy imaging results suggested that the HPH-NPs had a circular shape and the surface structure of HPH-NPs was compact. Circular dichroism spectrum and intrinsic fluorescence spectrum revealed that the secondary and tertiary structures of lysozyme changed due to the HPH treatment. By non-covalent binding with xanthan gum, the surface hydrophobicity of lysozyme increased. Fourier transform infrared spectroscopy results indicated that the hydrogen bonding and electrostatic interaction may be the major factors causing the formation of HPH-NPs. The HPH-NPs exhibited a good solubility, emulsification and antimicrobial activity. Therefore, our HPH-NPs material has a good potential use as the beverage ingredient for inhibiting the pathogen growth, and in turn benefiting the resultant products with a good safety.