Investigations on head drooping In head-on processed prawns

Abstract

Head drooping is the major quality problem associated with processing of headon prawns. The head drooping in head on prawns refers to the condition of oozing out of hepatopancreatic juice resulting from the breakage of the arthrodial membrane, which connects cephalothoraz of prawn to abdomen dorsally. The susceptibility of prawns to head drooping depends on the stability of the arthrodial membrane which in turn is determined by its biochemical composition. In this connection various biochemical constituents of the arthrodial membrane such as protein, phospholipid, moisture, calcium and cholesterol were analysed for two specied of prawn, Penaeus indicus and Penaeus monodon under three size groups (30/40, 50/60, and 70/80 pieces /kg). The activities of various hydrolytic enzymes of the hepatopancreas were also studied. The various biochemical constituets showed significant difference between species. Within the same species a size wise variation in the constituents of the arthrodial membrane and enzyme activity of hepatopancreas was observed. The various unit process such as hauling time, ice storage durations, freezing methods, cold storage durations and thawing methods were studied individually for their influence on head drooping. The study shows that the major determinants of head drooping in prawns are the biochemical composition of the arthrodial membrane and the easiness with which the hydrolytic enzymes of the hepatopancreas are released on postmortem handling and processing.