Protein isolate from seed of mesquite bean (P. juliflora (SW) D.C) were modified with acetic anhydride at concentrations 5, 10, 20 and 30% (ml per 100 g of protein) thus resulting 69.5; 83.2; 89.7 and 91.1% modification of available lysine. Functional characteristic of protein isolate was studied in native and acetilated form. Protein isolate in native form presented high solubility at acidic and basic pH, except in the pH range of 4 to 6. Acetilation shifted the isoelectric point of the proteins pH 5.0 to a pH 4.5; reduced the solubility at pH values below the isoelectric point and increased above pH 5.0, mainly at pH 7.0. The capacity of water and oil absorption of the native protein was small (1.89 and 1.04 g) and did not improve satisfactorily after modification. The effect of the modification on the foaming properties was higher in relation to the volume and foam expansion than its stability. Emulsifyng capacity of the acetylated protein isolate increased to the a higher extent, however, emulsifying activity and emulsion stability presented small variations in comparison to native protein isolate.
seed of mesquite bean; protein isolate; acetylation; functional properties
