Rheological study of giant squid surimi (Dosidicus gigas) made by two methods with different cryoprotectants added

摘要

Two new methods were designed for making surimi from giant squid (Dosidicus gigas) muscle. The first is based on protein precipitation at the isoelectric point (type A), and the second on washing with an acid solution (type B). Chemical analyses (e.g. protein solubility, electrophoretic profile), structural analyses (scanning electronic microscopy) and above all rheological analyses were carried out. Small amplitude oscillatory tests were performed to evaluate the influence of these two methods on the viscoelasticity and gel-forming ability of squid surimi. The results showed that method B preserves the functionality of the myofibrillar proteins better, thus making for a better gel structure than method A. Moreover, the addition of different cryoprotectants (sorbitol + sucrose, sorbitol + trehalose, trehalose alone), resulted in essential differences between the two kinds of surimi. In surimi A, trehalose favoured less initial protein aggregation and hence a thermorheologically stable structure, with a better gelation profile than sorbitol + sucrose or sorbitol + trehalose, in surimi, suwari-gels and definitive-gels alike. However, in B samples the influence of different cryoprotectants was not discernible.