Influence of adsorbed milk protein type and surface concentration on the quiescent and shear stability of butteroil emulsions

摘要

Understanding of the relationship between adsorbed milk protein layer characteristics and stability of butter oil emulsions may be applied to create emulsions with specific properties such as ice cream emulsions (quiescently stable, destabilizing under shear) formulated without chemical surfactant. Emulsions created from butter oil (25%) with dried skim milk (DSM) (0.2-0.7%), whey protein hydrolysate (WPH) (1.6-2.1%), whey protein isolate (WPI) (0.2-0.7%) and sodium caseinate (0.2-0.7%) were characterized for particle size distribution, protein surface concentration and relative stability when whipped. The DSM emulsions destabilized immediately after formation, possibly because of bridging flocculation. The levels of WPH required for quiescent stability prevented whipping-induced partial coalescence. At >0.3%, WPI and sodium caseinate produced quiescently stable emulsions. Destabilization during whipping decreased as protein concentration increased. Whey protein isolate at 0.3% was the most suitable for producing an emulsion with the properties of an ice cream emulsion.