Linear viscoelasticity and microstructure of heat-induced crayfish protein isolate gels

Linear dynamic viscoelastic properties have been used to evaluate the influence of heat processing on the microstructure of crayfish protein isolate (CFPI) in order to explore the potentials of crayfish in the production of surimi-like gel products. CFPI dispersions have been subjected to a temperature cycle that consisted of a constant heating rate temperature ramp and a rapid cooling step, following the transitions taking place in the system through the evolution of G' and G '', under different CFPI concentrations and pH Values. The influence of CFPI concentration and pH on linear viscoelasticity functions of CFPI aqueous systems before and after thermal processing has also been analysed. Occurrence of a gel-like behaviour has been found for CFPI dispersions. The mechanical spectra of CFPI gels have revealed a remarkable enhancement in gel strength by thermal processing. An apparent gel network enhancement has also been found by increasing the CFPI content or reducing the pH, excepting at the isoelectric point. The strong dependence of microstructure on pH found for thermally processed CFPI gels has been confirmed by Electron Microscopy. (C) 2008 Elsevier Ltd. All rights reserved.