Precipitation/Solubility of Proteins

Most of the functional properties are  dependent on the degree to which the proteins are soluble. The solubility behaviour provides a good index of potential application of proteins. This   is so  because  the  degree  of insolubility  is probably the most practical measure  of  protein denaturation and aggregation and because proteins that initially exist  in  a  denatured, partially aggregated  state,  often  have an impaired ability  to  participate  effectively  in gelation, emulsification and foaming.

Note, in  general, proteins, which are highly soluble, may be used in applications where emulsification, whipping and film  formation are   important  whereas  low  solubility  may  be   desired   in applications   with   high  protein  levels  and   when    limited emulsification or protein-protein interactions are needed.

Solubility of proteins is markedly and irreversibly reduced when heating is involved.  However, heat treatments  may be unavoidable to achieve other objectives (microbial inactivation, removal of off-flavor, removal of water and others).