Differential thermal analysis of frozen food systems II. Micro‐scale studies on egg white, cod and celery

Publisher Website
Google Scholar
Abstract
Summary: The freezability of water in a few representative food materials has been studied by differential thermal analysis (D.T.A.) and differential scanning calorimetry (D.S.C.) on a micro‐scale over the temperature range down to — 180°C. The materials were studied both in their original state and after extraction of low molecular weight water‐soluble constituents. In the case of egg white the effect of heat‐denaturation was also examined. Values are given for the amounts of unfreezable water in these various materials determined by the method described in the first paper in this series. In addition to the thermo‐dynamic irregularities attendant on thawing, other thermal irregularities were found to occur in each material, both in samples containing freezable water and in those at moisture contents below the limit of unfreezable water. The latter irregularities are interpreted as being due to changes in the condition of water within the unfreezable fraction, the constituent water of which is therefore considered to exhibit at least two different degrees of molecular mobility.