Influence of Various Milk Protein Isolates on Ice Cream Emulsion Stability

The adsorption of protein to the fat globule surface in an emulsion such as ice cream mix has a large influence on the resulting emulsion stability and on the fat destabilization process that occurs upon whipping and freezing the mix into ice cream. The performance of several milk protein preparations in an ice cream system have been examined. Enhanced levels of whey proteins at the fat globule surface, arrived at through either a selective homogenization process or an enhancement of the whey protein:casein ratio in the mix by addition of whey protein concentrate (36% protein), contributed to a decrease in the lipid-serum interfacial tension, a slight increase in mix viscosity, an increase in ice cream dryness upon freezing, and an increase in the amount of fat destabilization in the frozen ice cream. However, 95% whey protein isolate contributed more to desirable properties in the ice cream mix and frozen product. Several caseinates were also examined and sodium caseinate contributed to enhanced overrun in the ice cream but resulted in an emulsion that was too stable to produce the desired degree of fat destabilization upon ice cream manufacture.