A method for estimating glass transition temperature of powders by discoloration of Betanin under temperature-programmed heating conditions

Abstract

A simple and cheap method for estimating the glass transition temperature (Tg) of powders was proposed. This involved measuring the discoloration process of a dye added to the powders under temperature-programmed heating conditions. The method was applied to evaluate the Tg values of mixtures of maltodextrin and fructose, containing betanin, a natural dye. The Tg values obtained by this method almost agreed with those calculated by the Couchman and Karasz equation using the Tg values for constituents in the mixture, thus indicating the validity of the method.