Functional Characterization of Protein Stabilized Emulsions: Effect of Processing.

In order to evaluate the emulsifying characteristics of a protein the effect of processing of a protein stabilized soybean oil‐in‐water emulsion on the creaming stability of the emulsion was investigated. Three protein systems were used, namely soybean protein isolate, sodium caseinate and whey protein concentrate (WPC). The effects of four different types of emulsifying equipment, an ultra‐turrax, a Sorvall omnimixer, a valve homogenizer and an ultrasonic apparatus were studied. It was found that the type of emulsifying apparatus, the emulsifying time and intensity had a marked influence on the properties of the protein stabilized emulsions. It was demonstrated for all the types of apparatus and proteins used, that by increasing emulsifying intensity and time better emulsions, when characterized by the creaming method, are obtained up to a certain limit whereupon there is nothing to be gained by an additional increase of these factors. The necessary emulsifying intensity and time to obtain a certain stability range differed considerably according to the various proteins investigated as well as environmental conditions. This intensity‐time dependence may be considered as an emulsifying characteristic of the protein.