|MadSci Network: Chemistry|
Gluten, gliadin and glutenin proteins are defined by solubility. See http://www.nature.com/nature/journal/v134/n3384/abs/134380c0.html. http://en.wikipedia.org/wiki/Gluten As you can see from the latter article, salt solution results in purer gluten. More about the 'impurities' (chiefly albumin proteins) removed by dilute salt solutions is given in http://www.friedli.com/research/PhD/gluten/chap2.html In general, proteins are described phenomenologically as water-soluble, salt-soluble, alcohol-soluble, acid- or alkalai-soluble and insoluble. Nowadays proteins can be described accurately by primary, secondary, tertiary and quatenary structures.
Try the links in the MadSci Library for more information on Chemistry.