Bovine bone protein-quercetin conjugates for improved physical and oxidative stability of oil-in-water emulsions
Jingya Chen, Cenchen Ran, Pan Li, Jiaxin Jin, Junrong Zhou, Yilin Ye, Shiling Lü, Juan Dong, Qingling Wang
Abstract
To enhance the functional properties of bovine bone proteins (BBP) for food-related applications, their quercetin conjugates (BBP-QC), with antioxidant and emulsifying properties, were prepared by alkaline induction. The structural changes of BBP-QC conjugates were investigated, and their different concentrations were examined for the physical and oxidative stability of oil-in-water (O/W) emulsions. Structural characterization using Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectroscopy confirmed the covalent binding of QC with BBP resulting in a conformational change in BBP. Particle size and ζ-potential measurements showed that 0.6% BBP-QC effectively improved the physical stability, increased the net charge of the O/W emulsion. Fluorescence microscopy observation of emulsion microstructure showed that the distribution of oil droplets in the BBP-QC stabilized emulsion was smaller and more uniform than that without the conjugates and effectively alleviated the phase separation in the emulsion. The 0.6% BBP-QC emulsion had a peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) value of only 1.45 mmol/kg and 3.32 μmol/kg after 12 days. Additionally, BBP-QC stabilized emulsions exhibited excellent antioxidant capacity in vitro antioxidant experiments. This study highlights the excellent properties of BBP-QC conjugates as novel emulsifiers with high antioxidant activity and potential applications in the food industry.