EFFECT OF WET EXTRACTION METHODS ON THE EMULSIFYING AND FOAMING PROPERTIES OF LUPIN SEED PROTEIN ISOLATES (LUPINUS-ALBUS SSP. GRAECUS)

The emulsifying and foaming properties of lupin seed protein isolates (LSPI) prepared by wet extraction methods, such as isoelectric precipi tation, dialysis and polyacrylamide gel, were investigated The various LSPI differ from each other in many ways. The isolate prepared by iso electric precipitation mainly contains the globulin but not the albumi n fraction, while the other two isolates prepared by dialysis and poly acrylamide gel methods contain all the protein fractions and a conside rable amount of polysaccharides. The protein-polysaccharide complexes enhance emulsion stability due to steric repulsion effects. Foam expan sion is dominated by the surface activity and availability of protein in the solution, while foam stability is determined by the properties of the interfacial layer Both foam properties intensified from the pre sent of protein-polysaccharide complexes.