Stability of emulsions containing a whey protein concentrate obtained from milk serum through carboxymethylcellulose complexation

A protein concentrate (66.2% (w/w) in protein) was obtained from bovine milk whey by complexation with carboxymethylcellulose (CMC) and its ability to stabilize oil-in-water emulsions (φ: 0.10) against creaming and oil droplet coalescence was investigated. The emulsion samples were remarkably stable against droplet coalescence while their stability, with respect to serum separation and creaming, depended on environmental conditions (pH, NaCl content) which affected the whey protein–CMC interactions at the droplet surfaces. The results are discussed in terms of the formation of a droplet network, where limited ‘bridging’ interactions, due to adsorbed CMC molecules, play a critical role in stabilizing network structure against gravitational stresses.