Isolation and foaming functionality of acid-soluble protein from lupin (Lupinus angustifolius) kernels

BACKGROUND: Australian sweet lupin (ASL) protein is conventionally isolated by alkaline extraction/acid precipitation, leaving a waste stream containing acid-soluble proteins (ASPs) and contaminating raffinose family oligosaccharides (RFOs). The foaming functionality of ASP isolated from ASL is not known, but ASP from another lupin species has demonstrated high foaming functionality. RESULTS: Pre-soaking ASL kernels increased their protein/RFO ratio; however, some protein was lost by soaking. The foaming capacity of ASL protein isolated by different methods was ranked in the following order: alkaline extraction/isoelectric precipitation