Standardization of polyphosphate treatment for tiny prawns (Parapenaeopsis stylifera) with special reference to its rehydration capacity and organoleptic quality

In the present study, an attempt was made to explore the benefits of polyphosphate for enhancement of dried prawn (Parapenaeopsis stylifera) quality commercially known as "sode" in Maharashtra coast. Dip treatment in polyphosphate solution at different concentrations (viz., 3, 5, 7 and 10%) was given to pealed and no deveined P. stylifera for different durations (viz., 1, 2, 3, 4 and 5 min). Treated prawns were dried and subjected to rehydration capacity test and organoleptic evaluation. Among the different treatments, rehydration capacity was found to increase with the increased duration and concentration of treatment. Tiny prawns treated with sodium tripolyphosphate solution at the rate of 5% concentration for 5 minutes showed an increase in pH from acidic to alkaline, and had better quality with respect to rehydration capacity and textural attributes as compared to other concentrations and durations of polyphosphate treatment.

Phosphate treatment of frozen prawns. Pt 2. Frozen storage characteristics of prawn meat treated with polyphosphates

This communication reports the changes in physical, organoleptic and biochemical characteristics of prawn meat dip-treated with alkaline and neutral solutions of polyphosphates during frozen storage. Results are presented on changes in thawed and cooked yields, water extractable nitrogen, non-protein nitrogen, free amino-nitrogen, salt solubility, myosin and moisture in the muscle and loss of soluble nitrogenous constituents in thaw drip during frozen storage up to seven months. The salt solubility remained unchanged during storage in samples treated with neutral polyphosphate solutions and the organoleptic quality was superior to control sample. It is concluded that dip treatment with neutralized solutions of tripolyphosphate not only maintains correct drained weight and improves cooked yield during prolonged frozen storage but also protects the frozen product from denaturation as measured by the salt solubility of the proteins.

The effect of vitamins C and E on some of growth factors of cultured Acipenser ruthenus

The effect of vitamins C and E on some of growth factors of cultured Acipenser ruthenus was studied in this thesis. For this purpose diets supplemented with a combination of 100 and 400 mg/kg vitamin C, L-ascorbyl-2-polyphosphate and 100 and 400 mg/kg vitamin E, D-alpha-tocopherol,were each fed to sterlet in 2 replications for 15 weeks. Fifteen fish with average weight of 350.92±14.28 gr were distributed to each of 18 tanks after adaptation with experimental diet. After 5 weeks, there were significant differences in RBC, ESR, HCT and differential counting of white blood cells among the treatments (P<0.05), but there was no significant difference in the amount of WBC among the treatments (P>0.05). After 10 weeks, there were significant differences in the amounts of Monocytes, Lymphocytes and Eosinophils (P<0.05), but there was no significant differences in the amount of other hematologic factors (P>0.05). At the end of the experiment (15th week) only WBC, RBC, Monocyte, lymphocyte and neutrophil showed significant differences between the treatments (P<0.05) and other hematologic factors did not show any significant differences between the treatments (P>0.05). The results of biochemical indices analysis showed significant differences (P<0.05) among treatments for all of the parameters for 5th weeks, total protein and glucose for 10th week and only cholesterol for 15th week. The carcass analysis at the end of experiment showed that only the amount of carbohydrate, protein and ash were significantly difference between the treatments (P<0.05). The results of growth parameters at the end of 3th, 9th, 12th and 15th week showed significant differences between the treatments (P<0.05), but at the end of 6th week only GR was significantly different between the treatments (P<0.05). After concerning acute stress test including reduce water volume, cutting the aeration for 30 minutes at the end of experiment, cortisol and glucose significantly increased (P<0.05) compared with prestress period, but the lowest response to the stressor was observed in fish fed by E400 C 400 mg/kg. On the other hand the survival was 100% during the experiment and no mortality was occurred during this period. Results of this study indicate that Vitamins C and E can have remarkable effects on hematological, biochemical and growth indices in different growth periods. So regarding the effects of vitamin C and E on some growth indices, it seems that the diet containing E400 C 100 mg/kg can be considered as the optimum diet in the rearing condition for this weigth range of fish.