Mineralized calcium carbonate/xanthan gum microspheres for lysozyme adsorption.

Calcium carbonate/xanthan gum (Ca2CO3/XG) microspheres were prepared using biomimetic mineralization method for lysozyme (Ly) adsorption. The morphology of Ca2CO3/XG microspheres was characterized by field emission scanning electron microscope (FE-SEM). The Ly adsorption behavior was verified by Fourier transform infrared (FTIR) and in situ fluorescence microscope images. The effects of pHs on lysozyme adsorption were investigated as well. It was revealed that CaCO3/XG microspheres could immobilize lysozyme efficiently via electrostatic interactions with adsorption rate and adsorption quantity of 58.55 ±â€¯0.56% and 18.7 ±â€¯1.2 µg/mg as the pH was 7.0. Comparatively, the values markedly improved to 80.97 ±â€¯0.15% and 24.3 ±â€¯0.1 µg/mg respectively as the pH was 9.0 (p < 0.05). Additionally, UV and fluorescence spectrum showed that Ly maintained its original secondary structure during the adsorption/desorption process. The study therefore demonstrated that CaCO3/XG microspheres can be used as a practical and efficient support for Ly adsorption and desorption.

Interfacial and emulsion stabilized behavior of lysozyme/xanthan gum nanoparticles.

Interfacial adsorption kinetics and stabilizing emulsion behavior of lysozyme/xanthan gum nanoparticles (Ly/XG NPs) by variation of particle size and energy input. The interfacial rheology indicated that interfacial adsorption behavior of Ly/XG NPs displayed in a particle size manner. Increasing the particle size of Ly/XG NPs hindered its initial diffusion onto the interface. Smaller size was helpful for its fast diffusion to the interface. KP (rate constant of penetration) and KR (rate constant of penetration) of Ly/XG NPs were both affected by particle size. The KP for adsorbed Ly/XG NPs increased as the particle sizes increased. KR was considerably higher than KP, indicating the structural rearrangement of adsorbed Ly/XG NPs played an important part in interfacial film formation. The morphology of Pickering emulsion indicated its drop sizes were determined by the oil/aqueous volume fraction and prepared style. The higher energy input the size become smaller. Based on interfacial adsorption kinetics and microstructure of Pickering emulsions, the stabilization behavior was related to particle-particle associations and conformational changes of Ly/XG NPs. This work confirmed Ly/XG NPs could form Pickering emulsion by selecting different particle size and emulsification process, and offer promising prospects in stabilizing emulsion with the demands of surfactant-free.