Some physicochemical and functional properties of alfalfa soluble leaf proteins

Important physicochemical and functional properties of soluble leaf proteins (SLPs) from alfalfa herbage are presented. Subunits molecular weight (MW) distribution, denaturation temperature, and functional properties like, emulsification, foaming, and solubility are discussed. SLP concentrates were prepared by acid precipitation, and ultrafiltration of clarified alfalfa juice. The MW of major soluble protein component ribulose 1,5, bisphosphate carboxylase/oxygenase was estimated to be around 490 kDa. Denaturation temperature of soluble proteins was observed to be around 70–75 °C. Most of the functional properties were affected by concentrate preparation. Acid-precipitated SLP concentrate showed lowest emulsifying properties and nitrogen solubility. Heat stability of emulsions was good. Foam overrun for SLP concentrate depended on pH and was stable around protein's isoelectric point. Stress relaxation tests on 7/100 g SLP gels indicated that they were softer gels and relaxed faster compared to 13/100 g WPI gels. SLP preparations showed encouraging functional properties.