Esterified xylo-oligosaccharides for stabilization of Tween 80-stabilized oil-in-water emulsions: stabilization mechanism, rheological properties, and stability of emulsions.

BACKGROUND

Amphiphilic oligosaccharides have hydrophilic and hydrophobic subregions; therefore they can act like surfactants, while maintaining the viscous properties of the starting materials as stabilizers in emulsions. In the present work, xylo-oligosaccharides were modified by enzymatic esterification. Their emulsifying and stabilizing properties may improve the stability of emulsions, which could be explained by rheological properties.

RESULTS

The degree of substitution (DS) of esterified xylo-oligosaccharide ranged between 0.042 and 0.066. The esterified xylo-oligosaccharide was adsorbed on to the surface of the oil droplets. The critical flocculation concentrations (CFCs) of Tween 80-stabilized emulsions containing native and esterified xylo-oligosaccharide were 140 and 190 g kg(-1) , respectively. At concentrations below CFC, no creaming or flocculation was observed and the flow behavior of emulsions was Newtonian. At concentrations above CFC, emulsions containing native and esterified xylo-oligosaccharide showed extensive flocculation of emulsion droplets; consequently, shear-thinning flow behavior was expressed. Further increases in the concentration improved the creaming stability. The concentration and type of esterified xylo-oligosaccharide influenced the rate of creaming, whereas flow behavior of emulsions containing esterified xylo-oligosaccharide was clearly induced by concentration.

CONCLUSION

Esterified xylo-oligosaccharides have potential as emulsifiers and stabilizers, since they extended the CFC and were more effective in preventing creaming, compared with the native species.