Abstract: This paper was to study the effects on NSI, emulsibility and foaming ability of SPC (Soy Protein Concentrate) in different pH. The structures of SPC were analysed by electrophoresis and infra-red spectrum so as to study the principle of increasing of NSI and improvement of emulsibility and foaming ability of SPC. The results showed that with the increasing of the pH, the NSI of SPC increases quickly, the NSI at pH 12.0 is much higher than that of at pH 7.0. Emulsibility and foaming ability are improved with the increasing of the NSI. The electrophoresis showed that the subunit of SPC does not dissociate during modification; but the structures of SPC are changed by infra-red spectrum.

Key words:  , soy protein concentrate(SPC)； solubility； emulsibility； foaming； infra-red spectrum； nitrogen solubility index(NSI)；