Some Physicochemical And Nutritional Properties Of A Sweet Lupin (lapinus Albus Var. Multolupa) Protein

The lupin variety utilized in this study contained between 38-40% crude protein on a dry basis. The proteins were 55% soluble in water and 80-85% soluble in aqueous alkaline solution at pH 9.0. The pH of lowest solubility was 4.5. Fractionation of the alkaline extract by gel filtration on Sephadex G-100 gave three elution peaks. Sucrose gradient centrifugation furnished three bands with sedimentation coefficients of 8.1, 2.8, and 1.2 S, and the calculated molecular weights (mol wt) were 163 000, 53 000, and 9000, respectively. Electrophoresis on polyacrylamide gel revealed six protein bands. When the sample was treated with mercaptoethanol and sodium dodecyl sulfate (SDS) and the gel prepared in the presence of SDS, a maximum of 11 polypeptide monomers was detected ranging in molecular weight from 5500 to 66 000. Methionine was the first limiting amino acid and addition of 0.15% DL-methionine based on the protein raised the protein efficiency ratio from 0.9 to 2.2 for the rat. © 1978 American Chemical Society.2661438144