Influence of pregelatinized and granular cold water swelling maize starches on stability and physicochemical properties of low fat oil-in-water emulsions

The stability, color, textural parameters, rheological properties, zeta potential, surface and interfacial tensions of oil-in-water emulsions stabilized by pregelatinized (PG) and granular cold water swelling (GCWS) starches were investigated and compared with each other. The emulsions showed a pseudoplastic behavior over the studied shear rate range. Nevertheless, the pseudoplasticity of the emulsions was increased with starch concentration. Apparent viscosity, consistency coefficient (k) and flow behavior index (n) values were higher for the emulsions with GCWS starch compared to the emulsions made with PG. The textural parameters obtained from back-extrusion test increased with starch concentration and GCWS starch had greater values for all of the measured parameters. Both modified starches increased the emulsion stability however, the samples incorporated with GCWS starch were more stable during storage period. The zeta potential of the control emulsion was more negative than starch stabilized samples and PG containing samples were less negatively charged. However, starch concentration did not affect the zeta potential. The lightness increased while the yellowness decreased with starch concentration and GCWS samples were brighter and less yellowish. The surface and interfacial tensions were reduced with the increase of modified starches and GCWS was more effective in reducing these values.