Molecular, functional and nutritional properties of chickpea (Cicer arietinum L.) protein isolates prepared by modified solubilization methods

Abstract

Amongst different pulses, chickpea is a cost-effective legume in managing protein malnutrition and achieving food security. Chickpea is rich in protein and body building essential amino acids. Chickpea protein isolates from both desi (K850) and kabuli (P1108) cultivars, were prepared from defatted whole seed flour by sodium hydroxide (K1, P1), after removal of polyphenol (K2, P2) and solubilisation by sodium sulphite (K3, P3). The solubilised protein was isoelectrically precipitated (pH-4.3) by HCl and then freeze-dried after washing with water. Amino acid profiling and SDS-PAGE of K1 and P1 were also performed. Proximate data show that, protein content was highest in P1108 isolates (P3) prepared by sodium sulphite (98.65%) and Water Holding Capacity was also high in P3 (395.54%). Oil Holding capacity was highest in P2 (445.62%) prepared after polyphenol removal. Effect of pH, NaCl concentration and temperature influenced solubility, emulsion activity index (EAI), emulsion stability (ES), foaming capacity (FC) and foaming stability (FS). Protein isolates had better functional properties than flour. Solubility was highest at pH 11 in P1 isolate (79.29%) and for 1% NaCl concentration the solubility in P2 was 30.06% and 77.5% at 50 °C. Both EAI and ES were highest at pH 11. Not much difference was observed in EAI at 0.1% and 1.0% NaCl concentration. FC and FS were high at pH 11 and pH 5, respectively. Kabuli isolates formed gel at 10% concentration, whereas K1 and K2 at 16%. Isolate structure was micrographed by SEM. Kabuli protein isolates had better nutritional and functional properties.