Thumbnail Image

Theses

Browse

1994 - 19963
Reset filters
Subject: Fisheries × End date: 1997 × Start date: 1994 ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemOpen Access
    Investigations on head drooping In head-on processed prawns
    (Department of Processing Technology, College of Fisheries, Panangad, 1994) Jose, V T; KAU; Sherief, P M
    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.
  • Thumbnail Image
    ThesisItemOpen Access
    Vitamin C requirement and its deficiency syndromes in Macrobrachium Rosenberg II juveniles
    (Department of Aquaculture, College of Fisheries, Panangad, 1996) Gijo Ittoop; KAU; Sebastain, M J
    An experiment was conducted to study the influence of dietary vitamin e on growth, survival, food conversion ratio, moulting rate and whole body ascorbic acid content of juvenile Macrobrachium rosenbergii, to determine the optimum dietary requirement of vitamin e and to characterise the deficiency syndromes, if any. Juvenile prawns kept under defined environmental conditions were fed casein based semipurified diets containing eight levels of vitamin C. CVC - F 90, a hydrogenated vegetable oil coated form of vitamin C with 90% available ascorbic acid was used as the vitamin source. Growth, survival, food conversion ratio, moulting rate and whole body ascorbic acid content were found to be significantly affected by dietary vitamin C (P≤ 0.01). Below a level of 75 mg CVC - F 90 per kg of dry diet, deficiency syndromes like poor growth, survival and food conversion, incomplete moulting and black lesions at the tip of walking legs were noticed. The maximum weight gain of 194.92% was obtained with a dietary level of 150 mg eve - F 90 per kg dry diet. Non-linear regression estimate based on percentage weight gain showed the optimum requirement to be 200.3 mg CVC - F 90 per kg dry diet which is equivalent to 182.97 mg AAE / kg dry diet. The tissue ascorbic acid level seemed to reflect dietary levels of Vitamin C. About 15 µ gm tissue ascorbic acid / g was required for maximum growth and survival.
  • Thumbnail Image
    ThesisItemOpen Access
    Studies on the effect of purging the freshwater prawn Macrobrahium rosenbergii in extending its iced storage life
    (Department of Processing Technology, College of Fisheries, Panangad, 1995) Sudhir, B; KAU; Krishnakumar, S
    In this study the effect of purging the prawn Macrobrachiumrosenbergiito improve its quality during iced storage was studied. Various biochemical and sensory changes that occurred during iced storage was observed. Experiments were done both for headless and headon prawns. For the headless prawns the treatments were (1) freshwater purged, and (2) purged and further chlorine dipped and the purging time was 5 hrs in a 500 litre tank. For the headon prawns purging in running water in a 5000 litre tank for 18 hrs was done. Both experiments were done with a control of unpurged prawns. The headless prawns kept longer than the head on product style more so perhaps due to the effect of beheading. Analysis of variance for alpha amino nitrogen, TVB, NPN, pH and sensory evaluation showed significant difference between purged and unpurged samples in the headon product sytle, the purged sample being of better quality. Similar results were not evident in the case of headless scampi. Longer duration of purging for 18 hrs or longer seems to have an influence on quality. For the headon prawns the acid insoluble ash showed a significant difference between treatments indicating the success in flushing the gut contents by purging. Sensory evaluation showed that headless and headon prawns were acceptable for more than 10 and 7 days respectively. Mushiness was not observed in the headless prawns but started from the third day for the headon control and the fifth day for the purged prawn. In headon prawn presence of black vein was reduced considerably by purging. Thus it was seen that there was an improvement in the general quality of the prawn due to purging.