Modification of glass transition temperature through carbohydrates additions: effect upon colour and anthocyanin pigment stability in frozen strawberry juices

This work forms part of a collaborative research project between members of the EU Concerted Action CT 96-1180 "The preservation of frozen food quality and safety throughout the distribution chain". The objective was to investigate how added carbohydrates affect the colour stability of frozen strawberry juices stored at high temperature, i.e. above T(g') the glass transition temperature of the maximally freeze concentrated phase. Differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and de conductivity measurements were used to determine T(g'). It was found that there was no clear relationship between the anthocyanin loss and the amplitude of the difference between the storage temperature and T(g') the glass transition temperature of strawberry juices. (C) 1999 Canadian Institute of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.