The Effects of Protein-Rich Fraction and Defatting on Pasting Behavior of Chickpea Starch

Abstract

Starch and protein-rich fractions were isolated from both defatted and undefatted chickpea flour. Starch with a high purity was obtained by the isolation method used. Each of the protein-rich fractions was added to the respective starch fraction at different levels to obtain mixtures with a range of protein contents. The viscosities of these mixtures were analyzed using the Rapid Visco Analyser (RVA). Increased protein content of the starch and protein-rich fraction mixtures, obtained from defatted chickpea flour, resulted in distinctive resistance to shear thinning. The same behavior was not observed in case of starch and protein-rich fraction mixtures obtained from undefatted chickpea flour. Undefatted samples exhibited a sharp pasting peak in RVA curves as generally expected from starch-based systems, but unexpectedly, a sharp peak was not observed in defatted samples having protein content up to 4.8%. Peak, breakdown and cold-stage viscosity values of the mixtures obtained from undefatted chickpea flour were higher than those of defatted ones at the corresponding protein levels. The results implied that the lipids and their interaction with starch played an effective role in the gelatinization, pasting and cooling stage viscosity values of the RVA curves.