Influence of microcrystalline cellulose on the microrheological property and freeze-thaw stability of soybean protein hydrolysate stabilized curcumin emulsion

The impact of microcrystalline cellulose (MCC) on the physical stability, microrheological property and freeze-thaw stability of papain hydrolysate of soybean isolate protein (SPIH) stabilized curcumin emulsion was studied. Curcumin emulsions were prepared by Microfluidizer containing SPIH and various concentrations of MCC. The curcumin emulsions were assessed by zeta potential, average particle size through dynamic light scattering technique (DLS), stability index by Turbiscan and microrheological behavior through diffusive wave spectroscopy (DWS) technique. With addition of MCC, the negative charge of the droplets was increased, which indicated that the negatively charged fraction from MCC interacted with the protein at the interface. An increase in droplet size and decrease in TSI were noted with increasing MCC concentration. It demonstrated that enough MCC changed microrheological property of curcumin emulsions from purely viscous to viscoelastic over the range of decorrelation times, indicating that the droplets were not free to move due to the droplets network interaction. Freeze-thaw stability analysis demonstrated that MCC brought about a remarkable improvement, which can be attributed to the enhancement of repulsive steric forces between the curcumin droplets. It demonstrated that combined enzymatic hydrolysate of protein and addition of polysaccharide MCC could be an effective method for protecting bioactive compound in emulsions.