Rheological method for determination of critical concentration of pectin dispersion – A review

Abstract

Pectin critical concentration is a parameter that determines the effectiveness of pectin as a thickening and gelling agent. A lower critical concentration indicates the ease of a particular hydrocolloid to thicken the solution or form gel. From the industrial point of view, this is of interest as it entails a lower production cost. This review examines the critical advantages and limitations of various methods in determining the rheological-based critical concentration of pectin. The methods discussed in this work were based on dynamic viscosity flow pattern (η) plotted against shear rate (γ̇), apparent viscosity (η_app), zero shear viscosity (η₀), and consistency index (K) plotted against concentration (c), and specific viscosity (η_sp) plotted against the dimensionless number (c[η]). Empirically, these methods have been shown to successfully predict critical concentrations of pectin. However, models that can be used generally for each type of pectin flow are (1) η₀ plotted against c and (2) η_sp plotted against c[η]. Conclusively, this review provides information for industries and researchers to select a suitable method for analyzing the critical concentration of pectin where variations might be present due to different sources and methods for extraction.