Functional properties of proteins define their behaviour in a food system during production and processing. Extraction and isolation of proteins from plant seeds is only the first step to integrating these proteins into food products. If they are to be of use as food ingredients they have to prove sufficiently functional to be used in place of current food proteins, such as milk, egg and soy proteins. Studies of the functional properties of new protein sources can provide valuable information on the potential effectiveness of the proteins in food products. The important functional properties of proteins in food applications are solubility, swelling and water/fat holding capacity, emulsifying activity and emulsion stability, foaming ability and foam stability and gelling capacity.