Functionality of lupin seed protein isolate in relation to its interfacial behaviour

The foaming and emulsifying properties of lupin seed protein isolate (LSPI) were investigated following protein structure modification by heating and/or dithiothreitol (DTT) addition. Heat-treatment of protein solution resulted in an increase of both foamability and foam-stabilization ability while disulfide bond reduction by DTT brought about an improvement in the protein foaming capacity only. Additionally, heat-treated LSPI solutions exhibited markedly improved emulsification and emulsion-stabilization properties. Disulfide bond reduction, on the other hand, brought about an increase in the ability of the protein to stabilize the emulsions against creaming only. The influence of lupin protein structure modification on its solubility and surface-adsorption properties has also been studied in order to elucidate the protein structure/functionality relationship of lupin protein. (C) 2002 Elsevier Science Ltd. All rights reserved.