Understanding the Inhibitory Mechanism of Exogenous Protein on Enzymatic Preparation of Resistant Starch

Abstract

Enzymatic synthesis of resistant starch strongly depends on the food composition and their interaction with exogenous/endogenous proteins during preparation process. Therefore, the present study systematically investigates the inhibitory effect of egg albumin on pancreatic‐α‐amylase for synthesis of resistant starch from maize flour. The maximum inhibitory concentration of egg albumin is 5 mg mL−1 with % inhibition of 95.15% for pancreatic‐α‐amylase. Lineweaver burk plot reveals that Vmax is constant with and without addition of egg albumin. Whereas Km is increased in presence of albumin to achieve the same Vmax. Increase in the substrate concentration (Km) from 5 to 25 mg mL−1 leads to a decrease in enzyme inhibition. Moreover, the resistant starch content of enzymatically prepared resistant starch with and without albumin as compared to gelatinized maize starch (control) is increased. Scanning electron micrograph reveals interaction of egg albumin with maize starch as thread like aggregation. FTIR and XRD analysis reveal the increase in crystallinity of enzymatically treated maize starch against control. Moreover, egg albumin is negatively associated with enzymatic hydrolysis by preventing its access to maize starch granule and act as a competitive inhibitor. As a result of this interaction decrease in resistant starch yield from maize starch is investigated by enzymatic treatment.