The rheological behavior of corn oil emulsions prepared by high pressure homogenization (HPH) was investigated. Coarse emulsions of corn oil (10-30 g oil/100 g emulsion) in casein dispersions containing 0.5-3.5 g micellar casein/100 g casein dispersion in an oil-free basis were homogenized at 0-300 MPa. Flow behavior under continuous increasing (0-150 s-1) or decreasing (150-0 s-1) shear rate was tested. Emulsions that showed macroscopic change in consistency were tested for viscoelasticity (G′). Homogenization of emulsions with low oil concentration (10 g/100 g) resulted in Newtonian behavior for all treatment pressures. The rheological behavior of emulsions with higher oil concentration (30 g/100 g) was dependent on casein concentration in the aqueous phase and varied from Newtonian to shear thinning. Homogenization pressures between 20 and 100 MPa induced the formation of a gel-like structure possibly through pressure-induced interactions between caseins surrounding adjacent droplets.
All Science Journal Classification (ASJC) codes
- Food Science