Emulsions stabilized by okra polysaccharides: Physicochemical, interfacial, and emulsification properties

This study provided a comprehensive investigation about the correlation between okra polysaccharide physicochemical characteristics, interfacial behavior, and emulsification properties. Six okra polysaccharides with distinct physicochemical properties were prepared and evaluated for their emulsification performance. The kind of acid used for extraction affected the molecular weight of polysaccharides, while extraction solutions with different pH influenced the molar ratio of monosaccharides and the degree of methyl-esterification (DM), thereby affecting the behavior of polysaccharides at the oil-water interface and emulsification properties. Okra polysaccharides with higher DM and RG-Ⅰ exhibited lower oil-water interfacial tension and thicker interfacial layers. Compared to the emulsion stabilized by okra polysaccharide extracted using citric acid solution at pH 2.0 (OPC-2), the emulsion stabilized by okra polysaccharide extracted using hydrochloric acid solution at pH 1.0 (OPH-1) exhibited significant advantages of smaller droplet size (0.56 μm) and less malondialdehyde content (6.25 μmol/kg oil). Under pH 2.0, OPH-1 demonstrated the highest viscosity (290.12 mPa·S), along with the strongest G' (42.12 Pa) and G" (25.79 Pa), playing crucial roles in sustaining emulsion stability. Moreover, under conditions of high ionic strength, the interaction between ions and okra polysaccharide molecules diminished the emulsifying ability and emulsion storage stability. This study provides significant insights into the performance of okra polysaccharides and polysaccharide-based emulsions, thereby guiding the development of efficient and stable emulsifiers.