Solubility and Water Absorption of Systems Containing Soy Protein Isolates, Salt and Sugar

Solubility and water absorption of three soy protein isolates in the presence of sodium chloride and sucrose were studied. Water absorption also was investigated in a system that contained wheat flour in addition to the isolates, salt and sugar. Sodium chloride affected nitrogen solubility index and water absorption of the isolates; sucrose did not. Similarly, sodium chloride affected water absorption in the flour-soy system, whereas sucrose did not. An apparent inverse relationship was observed between water absorption of soy protein isolates in the absence of flour and in combination with flour. Dough development times were shorter and doughs were less stable for flour-isolate mixtures than for flour alone.