Protein functionalities in aqueous food systems mainly refer to water solubility, emulsifying properties, foaming ability and gelling ability. Proteins with good solubility can produce aqueous foods with high protein content. Moreover, good solubility is normally an important precondition property for good emulsifying, foaming and gelling properties. Emulsifying ability is one of the most important functionalities of food proteins, since emulsions are common systems existing in various aqueous foods (McClements, 2005).Therefore, improvement of water solubility and emulsifying properties of oat proteins would extend their food-use applications.