Glass - and freezing transition of supercooled water confined in mesoporous materials and biological systems

Abstract

The behaviour of water confined e.g. in artificial meso- or nanoporous silica materials is intensively discussed in literature. In this paper, we present the results of Dynamic Mechanical Analysis measurements of water confined in biological systems (foods like e.g. bread, apple, turkey bone, etc.) as a function of temperature and frequency and compare them with results of water confined in artificial mesopores. Two types of cooling/heating protocols were used: slow (2 K/min) cooling/heating runs and quenching the samples from room temperature to 100 K prior to slow heating up to room temperature. We found striking similarities between the behaviour of water confined in mesoporous silica and biological systems, both, in the vicinity of the glass transition as well as in the freezing/melting transition region. The obtained results are discussed, using artificial meso- or nanoporous materials as a model system for advancing our understanding of the freezing and glass transition of water confined in foods and other biological systems.