DIELECTRIC RELAXATION BEHAVIOUR OF RAFFINOSE PENTAHYDRATE IN THE LIQUID AND GLASSY STATES

G. RUDERMAN; I.G. MOGILNER; J.R. GRIGERA

Montevideo, Uruguay

Conferencia; ICBP 2007; 2007

Thermal, mechanical and dynamic properties of concentrated sugar-water mixtures, and their temperature dependence, have become subjects of interest, because they govern the storage stability and processing characteristics of a wide variety of food and pharmaceutical products. In view of the high water sugar mole ratio of its stable pentahydrate, the  thrisaccharide raffinose appears most relevant. The literature describing such systems is limited. The present work was undertaken with the aim of contributing to an improved characterisation of the binary water-raffinose system. The  dielectric permittivity of raffinose pentahydrate has been studied in the supercooled liquid and glassy regions, in the frequency range 300Hz to 7MHz. At least two relaxation processes were identified. Both were Cole-Cole type. One of them resulted in a non-Arrhenius process. The other, was assumed to follow an Arrhenius equation and an (apparent) activation energy of 77.5kJ/mol was estimated.