Pasting of G-Irradiated Proteins from Vigna Subterranea in Native Starch Models and the Surface Functional Properties of the Proteins

Abstract

This research was carried out to evaluate the surface functional properties of gamma irradiated Bambara groundnut protein isolates and to study the pasting characteristics of the modified protein in native starch models using the Brabender Viscoamylograph. Irradiation was done at five levels: 2.50, 5.00, 7.50, and 10.00 kGy; while the pasting of the Proteins (P) was run in Starch (S) models of three combinations; 30P:70S, 50P:50S, 70P:30S. The results showed significant (p<0.05) effects of increasing irradiation doses on protein related surface functional properties, while pasting characteristics of the irradiated protein in the experimental range showed no significant dose-dependent (p<0.05) changes. There was characteristic starch paste behaviour on the other hand with increasing starch:protein ratios. Conclusively, correlation studies suggested that the pasting properties depended solely on the starch concentration within the admixture models indicating the insignificant contribution of modified Bambara groundnut proteins to the pasting properties in the models. Enhanced surface functional properties of the gamma irradiated proteins make them potential foaming and emulsifying agents in food applications. The starch-protein admixture models may also serve as a potential protein based thickening agents for foods that require various degrees of viscosity modifying effects.

Key words: Bambara groundnut protein, modified protein, gamma irradiated proteins