Effect of High-Hydrostatic Pressure and Temperature on Rheological Characteristics of Glycomacropeptide

Abstract

The influences of high pressure and temperature on the rheological characteristics of glycomacropeptide (GMP) were studied using a controlled rate rheometer. GMP dispersions at a concentration of 12.5% (w/w) were subjected to high pressure from 100 to 400MPa for 30min and temperature from 20 to 80°C for 15min followed by rheological measurements at a shear rate ranged between 0 and 200s−1. Shear stress-shear rate data of both pressure and heat induced GMP samples fitted Herschel-Bulkley model well with yield stress. It exhibited shear-thinning behavior with flow behavior index ranged between 0.882 and 0.996. Consistency coefficient and apparent viscosity increased with pressure up to 300MPa while those parameters decreased at 400MPa. The rheology of GMP was influenced by temperature. The consistency coefficient and apparent viscosity at 100s−1 obeyed the Arrhenius relationship with activation energies ranged between 8.17 to 12.38kJ/mol. Lower activation energy signified lesser molecular aggregation or unfolding of protein molecules during thermal treatment of GMP.