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 qualit y and safety throughout the distribution chain". The objective was to inves tigate how added carbohydrates affect the colour stability of frozen strawb erry juices stored at high temperature, i.e. above T-g' the glass transitio n temperature of the maximally freeze concentrated phase. Differential scan ning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and de conductivity measurements were used to determine T-g'. It was found that th ere was no clear relationship between the anthocyanin loss and the amplitud e of the difference between the storage temperature and T-g' the glass tran sition temperature of strawberry juices. (C) 1999 Canadian Institute of Foo d Science and Technology. Published by Elsevier Science Ltd. All rights res erved.