Synthesis and properties of fish protein‐based hydrogel

The novel use of fish protein (FP) in the manufacture of a superabsorbent hydrogel was investigated. Following the introduction of a large number of hydrophilic groups into fish protein by modification with ethylenediaminetetraacetic dianhydride (EDTAD), proteins were cross‐linked by sulfhydryl‐disulfide interchange reaction between the endogenous sulfhydryl groups and disulfide bonds to produce an insoluble gel structure. The water uptake of 76% EDTAD‐modified FP hydrogel was 540 g water/g dry gel at 214 × g , and it depended on pH and ionic strength of the solution. The structural changes in proteins consequent to modification were also investigated. EDTAD‐FP hydrogels had increased rigidity after glutaraldehyde treatment but displayed diminished water uptake characteristics.