Histological changes in collagen related to textural development of prawn meat during heat processing

Heat processing enhanced firmness and degree of shrinkage deformation of kuruma prawn Penaeus japonicus meat. In histological experiments, most collagen fiber in perimysium, epimysium, and subcuticular connective tissue maintained structures after heat-processing in hot water at 70 degrees C for 30 min. Crude collagen fiber fractions (residues after alkali extraction, RS-AL) prepared from the muscle were measured for hot-water solubility and compared with the RS-AL from the muscle of carp Cyprinus carpio, Collagen in the RS-AL of prawn muscle had very low hot-water solubility (about 23.5% at 70 degrees C) compared with that of carp. These results suggested that collagen had important functions in promoting thermal shrinkage and hardening of prawn meat and in maintaining mechanical strength of heat-processed meat.