The roe of rainbow trout was investigated with respect to the effects of maturation and technological steps on the differential scanning calorimetric (DSC) curves of yolk proteins. The DSC curves were markedly effected during the first phase of maturation, while on the whole almost no changes were visible in the later stage. DSC curves measured on yolk proteins of rainbow trout were clearly discernible from those of milt and muscle proteins of same species. Applying different technological treatments on the roe it became clear that freezing and frozen storage have only a minor influence on thermal behaviour of yolk proteins. On the other hand, lightly salting, heating on 90degreesC and high pressure processing (thawing) change the DSC curves markedly indicating a stronger denaturation of yolk proteins by these treatments. However. compared to the muscle proteins of rainbow trout the influence of high pressure was less. DSC curves of yolk proteins are influenced by fish species. However, it seemed not possible to use them for discrimination of species of the same family. (C) 2003 Elsevier B.V. All rights reserved.