Functional properties of native and chemically modified protein concentrates from bambarra groundnut

Protein concentrate (BNP) was prepared from bambarra groundnut (Voandzeia subterranean) and it was derivatised with succinic (BSP) and acetic anhydride (BAP). Chemical composition revealed significant (P < 0.05) increases in the moisture and ash contents following modifications, while the crude fat was reduced. Protein solubility reduced with increase in pH of the solution until it reached isoelectric points of 3, 3.5 and 4 for BSP, BAP and BNP, respectively, following which steady increases were observed for the proteins as the pH increased. The results indicate an initial increase in emulsifying activity (EA) with increase in protein concentration. Both acetylation and succinylation improved the emulsifying stability of the native protein. Foaming capacity of both native and modified proteins increased with increase in protein concentration. Except at pH 2, where BNP recorded higher foam capacity than the modified proteins, at all other pHs studied, both succinylation and acetylation improved foam capacity. Gelation studies revealed that initial increase in ionic strength enhanced gelation properties, while gelation capacities reduced at higher salt concentrations.