Journal of Nutrition & Food Sciences
Open Access

Abstract

The Effect of pH on Foaming Properties of Cowpea (Vigna ungiculata L.walp) Flour and Protein Isolates

Ikhlas Ibrahim Khalid and Sirelhatim Balla Elhardallou

The effect of pH on foaming properties on cowpea (Vigna ungiculata) seeds as whole cowpea flour (WCF), dehulled cowpea flour (DCF), dehulled defatted cowpea flour (DDCF) and cowpea protein isolates (CPI) obtained from DDCF by isoelectric (CPIA) and micellization (CPIB) precipitation was studied. The protein % was found to be 22.3% in (WCF) and 26% in (DDCF) flour, while 75 and 76% for CPIA and CPIB respectively. The foaming capacity (FC) and foam stability (FS) were greatly affected by pH values. FC of DDCF and CPIB showed minimum level at pH 2.0 while CPIA at pH 4.0. However, the FS of DDCF was highest at pH 5.0 while CPIA and CPIB were less stable. CPIB have poor FS compared to CPIA at all pH ranges (2-12). Maximum FS was observed at pH 9.0 for DDCF which remain stable up to standing period of 2 hr. CPIA form foam with highest initial volume and maximum FS was observed at pH 9.0. FC of all products was found to be higher at alkaline region of pH compared to acidic side. Defattening markedly increase the FC in the flours.