M. Thiebaud et al., BIOCHEMICAL CHARACTERISTICS OF THE PROTEI N CONSTITUENTS OF CRAB ANALOGS PREPARED BY EXTRUSION-COOKING, Sciences des aliments, 15(1), 1995, pp. 59-74
This study concerns an experimental crab analog (0.63 w:w water, 0.23
w:w protein) and a commercial crab analog (0.82 w:w water, 0.14 w:w pr
otein), both prepared by extrusion cooking of mixes containing Alaska
pollack surimi and egg white powder. Protein solubility was studied at
pH 8.0 and 10.6 in the presence of various dissociating agents. Solub
le protein extracts were analyzed by SDS-PAG-Electrophoresis. Results
were compared to those from an experimental heat-induced gel (kamaboko
type), having the same composition as the experimental crab analog. T
he heat-induced gel appears to be mainly stabilized by non-covalent in
teractions (hydrophobic, hydrogen and electrostatic). Myosin heavy cha
ins, which participate to the formation of soluble high molecular weig
ht aggregates, may be directly involved in the gel network. The solubi
lization of protein constituents from both extruded analogs requires s
trong dissociating conditions. Electrophoregrams show extensive molecu
lar rearrangements of both myofibrillar and egg white proteins. The in
tensity of the extrusion process appears to be responsible for reactio
ns such as hydrolysis and/or polymerization of polypeptide chains. Pro
tein texturization by extrusion cooking probably involves the formatio
n of numerous intermolecular covalent bonds (disulfide, probably isope
ptide, but not lysinoalanine).