New processing of lupin protein isolates and functional properties.

A growing demand for functional plant proteins could be identified, which properties are customized for specific applications and formulations as food ingredients. Native lupin proteins (alpha, beta, gamma) conglutin have a good solubility at appropriately chosen conditions. A novel procedure has been proposed to maintain the native protein properties. Lupin proteins are extracted from hexane deoiled lupin. The protein product type E comprises high molecular weight proteins (alpha, beta-conglutin), which are separated using alkaline extraction and acid precipitation procedures. The protein product type F is enriched in the gamma-conglutin fraction and is separated from the acid pre-extract applying cross flow filtration at pH 7-8. For the zirconium oxide membrane the filtration rate can be increased by appropriately chosen pH conditions up to 70 l/m2h. Lupin protein fraction (type E and F) are highly soluble protein isolates with outstanding emulsification, salt tolerance and foaming properties. These new lupin proteins (type E and F) offer extremely interesting properties for application in food systems and are available from pilot plant fractionation.