Obtaining and Rheological Properties of Pectin Isolated Using Microwave Radiation

Abstract

Objective: А method has been developed for extracting modified pectin from plant raw materials by using microwave radiation at the stage of washing. Methods: The rheological properties of 5.0% aqueous solutions of apple pectin obtained by exposure to microwave radiation of various powers: 300, 450 and 600 W, as well as pectins obtained by the traditional method at temperatures of 25, 40, 55, 70°C were investigated. Results and Discussion: It is shown that the use of microwave radiation can improve the method of obtaining pectins by increasing the yield of pectins and regulating their structure and properties. The rheological properties of concentrated aqueous solutions of pectins obtained by exposure to microwave radiation of various powers have been studied. It is shown that all studied systems of pectin solutions are non-Newtonian fluids with a pseudoplastic type of viscous flow anomaly, determined by the values of the microwave energy. The values of the apparent activation energies of the viscous flow of solutions, which are an indirect characteristic of the strength of the structures of the system, have been estimated. Data was obtained on the structure and changes in the structure of their concentrated solutions under the action of external forces and temperature in the course of a viscous flow. Conclusions: It is shown that the power values оf microwave radiation are the main factor determining the structure of molecular matrices of pectins and the structure of their concentrated aqueous solutions.