Emulsification of Scutellaria baicalensis Georgi polysaccharide conjugate and its inhibition on epigallocatechin (EGC) oxidation

Abstract The oil-in-water (O/W) emulsions were prepared from Scutellaria baicalensis polysaccharide conjugates (SBPC) as an emulsifier and medium-chain triglyceride (MCT). Effects of pH, metal ions and heat treatment on the emulsion stability were investigated. Compared to that of 0.20 1.00 wt% SBPC and 2.00 wt% GA, 2.00 wt% and 3.00 wt% SBPC stabilized emulsion droplets had a smaller particle size and were more stable during 10-day storage at 25 °C. The average particle sizes (d32) of emulsions containing metal ions varied from 4.54 to 6.62 μm (0.100-0.500 mol/L Na+), from 2.63 to 3.86 μm (0.010-0.050 mol/L Ca2+), and from 2.66 to 7.89 μm (0.001-0.030 mol/L Al3+), as well as the zeta potential varying from -17.63 to -19.67mV (Na+), from −16.50 to −18.13 mV (Ca2+) and from -15.02 to -18.56 mV (Al3+). SBPC emulsion possessed stability under pH 3.0-7.0 and thermal treatment at 70-100 °C during the 10-day storage period. Furthermore, SBPC emulsion inhibited oxidative polymerization of EGC. The average retention rate of EGC was 88.28% on the 10th day. This research provides a new way for development and application of SBPC as an emulsifier.