Evaluation studies on effects of pectin with different concentrations on the pasting, rheological and digestibility properties of corn starch.

In this paper, the effects of pectin (PE) with different concentrations on the pasting, rheological and digestibility properties of corn starch (CS) were evaluated. The Rapid Visco-Analyzer results showed that the peak viscosity was decreased with the concentrations of PE (0.5% and 1.0%) and then increased when the concentration of PE exceeded 2.0%. PE resulted in lower breakdown and setback values of CS. Rheological results revealed that the CS and CS-PE mixtures exhibited a pseudoplastic and shear-thinning behavior. The storage modulus (G') and loss modulus (G″) of CS were increased with increasing PE concentrations from 2.0% to 10.0%. PE resulted in a decrease in the starch susceptibility to α-amylase and promoted a remarkable reduction (P < 0.05) in the fraction of rapidly digested starch. The hydrolysis kinetic analysis suggested a decelerating effect of pectin on the hydrolysis rate of CS with lower values of equilibrium hydrolysis percentage (C∞) and kinetic constant (k).