A combination of green tea polysaccharide conjugate and bovine serum albumin and its emulsion-stabilizing characteristics

Abstract

Tea polysaccharide conjugates (TPC) and bovine serum albumin (BSA) have emulsifying properties, but they have certain shortcomings when used alone as emulsifiers. This study aimed to combine TPC and BSA to form a complex for applications to achieve the complementary advantages between them. The TPC/BSA complex was physicochemically characterized, and the results showed an improvement in its surface hydrophobicity. TPC/BSA emulsions with different concentrations (0.20–1.00 wt%) were prepared using TPC/BSA complex as the emulsifier. The effects of heat treatment, pH, and metal ions on the stability of TPC/BSA and BSA emulsions were investigated, and TPC/BSA emulsion systems loaded with epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were constructed. TPC/BSA emulsion droplets were smaller than 1.00 wt% TPC emulsion droplets, and the particle size of 0.20 wt% TPC/BSA emulsion increased slightly during storage at 25 °C. Further, 0.20 wt% TPC/BSA emulsions became less stable after heat treatment, whereas the particle size of other concentrations did not change significantly after treatment at 70 ℃–90 °C. TPC/BSA emulsions were more stable at pH 6.0–9.0. Both were less affected by Na+, weakly affected by Ca2+ than BSA emulsion, and significantly affected by Al3+. TPC/BSA emulsion had a good protection effect on EGCG and EGC. The presence of EGCG and EGC improved the stability of the emulsion system, which remained stable for 90 days.