Glass transition temperature mapping using magnetic resonance imaging

Representation of a system using an average glass transition temperature (T -g) value will become inadequate if the system is not sufficiently homogene ous in terms of physical structure and chemical composition. Many food syst ems are heterogeneous, and therefore a nonuniform distribution of T-g value s is expected. In this exploratory article, the basis for determination of T-g using nuclear magnetic resonance (NMR) techniques is discussed, and a m agnetic resonance imaging (MRI) method is proposed for determining the spat ial distribution of T-g in food systems. The T-g maps for maltodextrin and bread samples, obtained using this method, are presented.