Effect of ionic strength and/or pH on Extractability and physico-functional characterization of broad bean (Vicia faba L.) -: Protein concentrate

Protein extractability studies showed that the protein of broad bean (Viciafaba L.) was extractable at both acidic and basic pH. The percentage of pH-12 extractable protein that was precipitated at pH 4 (isoelectric point) from protein concentrate, dehulled full-fat seed flour and whole seed flour are 62.0%, 1.2% and 71.6%, respectively. Low ionic strength (mu <= 0.4) increased the solubility of the protein in the bean concentrate at acidic pH, while at alkaline pH, increase in ionic strength (0.1-2.0) had an inverse relationship on the concentrate protein solubility. The capacity to form protein-stabilized foam was least (34%) at pH 4 and highest (97%) at pH 12. These were increased to 62% (pH 4) and 139% (pH 12) in medium with ionic strengths of 0.2 and 0.4, respectively. The foam formed was more stable at pH 4 than at the other pHs. Low ionic strength of 0.1 improved water absorption capacity but reduced it at ionic strength of >= 0.6. (c) 2006 Elsevier Ltd. All rights reserved.