Abstract

Emulsifying functionality of milk proteins such as whey protein concentrate (WPC), whey protein isolate (WPI), casein, and enzyme-modified WPC, WPI, and casein was investigated in a O/W emulsion.  Enzyme-modified samples were selected based on the sensory evaluation and their functionality was tested in mayonnaise-like emulsion and compared to the mayonnaise emulsion prepared using egg components.  Casein and hydrolyzed casein were not used for making mayonnaise-like emulsion because of their undesirable taste and poor emulsion stability.  At a given concentration of protein, egg components provide smaller oil drops and creamier mayonnaise compared to WPC and WPI.  However, WPC provides a thicker mayonnaise-like emulsion compared to the egg proteins and WPI.  Both WPC and WPI provided products with much thicker texture.  However, the texture was not creamy compared to the emulsion containing the egg components.  Enzyme-modified WPC samples are significantly less functional than the enzyme-modified WPI samples.  Emulsifying functionality in mayonnaise was decreased as the level of WPI or enzyme-modified WPI was decreased.  At all protein levels studied, protease (Multifect Neutral)-treated WPI is more functional than transglutaminase-treated WPI.  Enzyme modification, in general, leads to a decrease in the emulsifying functionality of WPC and WPI in mayonnaise-like emulsions.

Key words: Milk proteins, whey proteins, WPC, WPI, casein, enzyme modification.