Rheological properties of enzyme-treated mango pulp

Abstract

Mango pulp was treated with pectinase enzyme at different times (30–150 min) and temperatures (25–60 °C) of treatment, and at various concentrations of enzyme (0.005–0.095%). The effect of these enzyme treatment conditions on the rheological parameters (yield stress, flow behaviour index and consistency index) and the apparent viscosity, were determined employing a second order central composite rotatable design in combination with response surface methodology. The raw, as well as the enzyme-treated, mango pulp behaved as pseudoplastic liquid and possessed yield stress. The Herschel-Bulkley model fits well ( r ≥ 0.991, p ≤ 0.01) the shear rate and shear stress data. An increase in time and/or concentration of enzyme treatment is associated with an increase in the flow behaviour index. Apparent viscosity markedly decreased with an elevation in the concentration of the enzyme.