Evaluation of emulsifying and foaming capacity of the legume flours and the influence of pH and ionic strength on these properties

In this study, functional properties of red bean, chickpea, lentil and canellini bean were evaluated. Our results revealed that beans had the highest emulsifying capacity. This property was minimum at the isoelectric point (about 4) among all samples which is in concistent with their solubility curves. Salt concentration of 0.5 M did not have a significant influence on emulsifying capacity but higher concentration (1.0 M) reduced this capacity significantly (P<0.05). Regarding emulsion stability, red bean flour had the highest index even at high concentrations of salt and different ranges of pH. The highest foaming capacity was related to red bean and canellini bean flours with an index of 68 and 64.5% respectively. At isoelectric point, all the samples had the lowest foaming capacity. Salt concentration was most effective on red bean flour foaming and among all samples, foaming stability greatly decreased by time. Finally, the highest foaming stability was found to be at the isoelectric point. Keywords: Legume flours, functional properties, ionic strength, emulsion stability, foaming stability