Utilizing protein-polyphenol molecular interactions to prepare moringa seed residue protein/tannic acid Pickering stabilizers

The formation of complexes between plant proteins and polyphenols is being explored for the development for functional ingredients with new or improved properties. In this study, complexes were fabricated from moringa seed residue protein (MSRP) and tannic acid (TA). Fourier transform infrared spectroscopy and isothermal titration calorimetry suggested that the main interactions between MSRP and TA were hydrophobic and hydrogen bonding. The MSRP-TA complexes had near neutral wettability (θow = 86.1°), which meant that they could adsorb strongly to oil-water interfaces and thereby form and stabilize Pickering emulsions. The stability of the emulsions was improved by optimizing the MSRP:TA ratio. Confocal laser scanning microscopy indicated that higher tannic acid concentrations enhanced the thickness and compactness of the MSRP-TA interfacial layers formed around the oil droplets. The physicochemical properties of the emulsions were measured over a range of pH (3–9) and ionic strength (0–0.4 M NaCl) conditions. These results showed that the complexes were able to form stable emulsions at lower ionic strengths (