Fabrication and characterization of emulsion stabilized by tannic acid/soluble potato starch complexes

In this study, the influence of tannic acid (TA)/soluble potato starch (PS) mass ratio and PS concentration on TA/PS complexes and emulsions stabilized by TA/PS complexes were studied. The size, hydrophobicity and emulsifying properties of TA/PS complexes were all controlled by TA/PS mass ratio and PS concentration. In detail, the hydrophobicity of PS (θ_ow = 48°) improved after complexing with TA to form TA/PS complexes (θ_{ow max} = 64°). The emulsions size decreased and then increased with increasing TA/PS ratio. Additionally, the emulsifying properties of TA/PS complexes improved by increasing PS concentration. Analysis of the interfacial tension after adsorption equilibrium (0.25 mass ratio, TA/PS complexes (13.03 mN/m), TA (14.21 mN/m) and PS (20.25mN/m)), TA and PS had a synergistic effect of stabilizing the oil-water surface. Among them, TA mainly played a role in emulsifying property, and PS mainly played a role of stabilization. All emulsions exhibited obvious creaming. However, at high PS concentration or TA/PS ratio, the creaming was prevented by formed smaller emulsion size, interface complexes networks or high viscosity (Increased from 0.004 to 0.060 Pa.s). It showed that TA/PS complexes can act as emulsifiers to improve the physical and oxidative stability of emulsions, making them suitable for delivering oxidation-sensitive fat-soluble bioactive compounds.