EFFECT OF EXTRACTION METHODS ON PROTEIN ISOLATE YIELD AND FUNCTIONAL PROPERTIES OF SOME LEGUMES

Three local samples of unsound (damaged soy - bean), decorti­cated lentil and broad bean (Vicia faba) were used as source of protein in this study. Ca (OH)₂ and NaOH methods were applied in protein isolate extraction. Protein extractability and precipitabifity were determined and results showed that NaOH method gave higher extractability than ca (OH)₂ method whil the precipitation value showed a reverse trend. Re­sults also show that broad bean residue after extraction of protein con­tain a pronounced amount of carbohydrate as strach , while soy - bean and lentil still had a relatively good balance of protein and carbohydrate contents and lentil residues could be used as good and well balanced feed stuff while broad bean might be used as a source of starch produc­tion. It could be concluded also that both extraction methods produce protein isolates with a very close purity which determined by the nitro­gen content or crude protein of the isolates. Generally , results show that the method of protein extraction had a little effect on the protein functional properties except that of the coagulated protein percent which increased in case of using NaOH, meth­od . As a conclusion the three damaged and unsound samples could pro­vide a good source of absorption capacity , which suggests potential use of these proteins as a meat binder or extender, and also in doughs and baker products.