Functional properties of flours and protein isolates from Phaseolus lunatus and Canavalia ensiformis seeds

The functional properties of flours and protein isolates from the legumes Phaseolus lunatus and Canavalia ensiformis were evaluated to determine their potential practical applications. The respective protein isolates were obtained from the flours by using isoelectric precipitation, with a protein content of 71.13% for the P. lunatus isolate (PPI) and 73.75% for the C. ensiformis isolate (CPI). Nitrogen solubility was good in both acid and alkaline pHs for isolates and Canavalia flour (CF), with values as high as 80%, but not for the Phaseolus flour (PF). The flours and protein isolates had good water-holding capacities, with values between 2.65 and 3.80 g/g sample. Oil-holding capacity was highest in PPI (4.59 g/g sample) and CF (3.15 g/g sample). Under alkaline pH, the PPI foaming capacity (147%) was higher than those for CPI and CF, though the flours produced greater foam. Emulsifying activities for the PF, CF, PPI, and CPI were similar (46.78-53.84%) for pH range 6-10. Emulsion stability (ES) was superior in the CF and the CPI, where values reached 100% at pH 7 and 8. Apparent viscosity was pH-dependent.