Muscle Ultrastructural Changes in Freshwater Prawns, Macrobrachium rosenbergii during Iced Storage

Deheaded and whole prawns ( Macrobrachium rosenbergii ) were stored up to 10 days on ice. Myofibrils, extracted from the first abdominal segment, were prepared for incubations at different ionic strengths (0.1 to 0.3 M) and subsequent SDS‐gel electrophoresis, while other samples were prepared intact for transmission election microscopy. Elevated ionic strengths in vitro increased the solubilization of specific myofibrillar proteins (such as myosin heavy chain); this effect was especially pronounced in prawns stored whole. Proteolysis was indicated in samples from whole prawns by the appearance of a family of proteins ranging in molecular weight from 65 kD to 180 kD. Loss of myofibrillar integrity was apparent by day 10, with losses more pronounced in whole prawns than in deheaded prawns.