Peer Reviewed Journal Articles (Inter.) (B&N)

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Browsing Peer Reviewed Journal Articles (Inter.) (B&N) by Author "Ammu, K."

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    Biochemical and nutritional changes in fish protein during drying
    (1995) Raghunath, M.R.; Sankar, T.V.; Ammu, K.; Devadasan, K.
    Biochemical and nutritional changes in the muscle proteins of a lean marine fish Nempizerra japordeus during drying at 50, 60 and 70‘t were investigated. Solubility of proteins in water, 0-6 m NaCI, 1-5 M urea, it m urea and 10 g litre-1 sodium dodecyl sulphate (SDS1 decreased as drying progressed at all three temperatures; most of the decrease occurring in the initial 4 h of drying. SDS-polyacrylamide gel electrophoresis of 1.5 M urea, 8 m urea and SOS extracts showed that higher molecular weight (MW) protein fractions were more sensitive to drying and disappeared much earlier from electropherograms than the lower MW protein fractions. Residual Solubility of proteins near the pH range of 4 6 was found to increase during drying, but solubility at acid and alkaline pH was adversely affected. Decrease of solubility by drying was more affected at acid pH, especially at higher temperatures than at alkaline pH. Sulphydryl groups registered a regular and sharp decrease with drying except at 50°C, where initially an increase was observed. Apart from disulphide and hydrophobic bonds, free amino groups also appear to be involved in denaturation reactions during drying. Pepsin digestibility of fish muscle decreased slightly during drying but a clear relationship with drying temperature was not evident. Highly significant differences in proteins between protein efficiency ratio (PER), net protein utilisation (NPU) and biological value were observed between the drying temperatures. The PER and NPU of fish dried at 60°C were significantly higher than those dried at 50 or 70°C.
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    Lipase activity in different tissues of four species of fish: rohu (Labeo rohita Hamilton), oil sardine (Sardinella longiceps Linnaeus), mullet (Liza subviridis Valenciennes) and Indian mackerel (Rastrelliger kanagurta Cuvier)
    (Wiley, 2003) Nayak, J.; Nair, P.G.V.; Ammu, K.; Mathew, S.
    Lipase activity in stomach and pyloric caeca, liver, intestine and red muscle of rohu (Labeo rohita Hamilton), oil sardine (Sardinella longiceps Linnaeus), mullet (Liza subviridis Valenciennes) and Indian mackerel (Rastrelliger kanagurta Cuvier) was studied. Distinct differences in lipolytic activity in different tissues of these fish were observed. Rohu showed the highest activity in all tissues in comparison with the other three species of fish. Among the three size groups of mullet, medium-sized mullet showed higher activity than the other two groups in all tissues except intestine. Rohu hepatopancreatic lipase exhibited more hydrolytic activity on fish oil than rohu intestinal lipase.
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    A study on the intestinal lipase of Indian major carp Labeo rohita
    (Asian Fisheries Society, Manila, Phillipines, 2004) Nayak, J.; Nair, P.G.V.; Mathew, S.; Ammu, K.
    Lipase from rohu(Labeo rohita, Cyprinidae) intestine was extracted, fractionated with ammonium sulphate and purified on Sephadex G100 column. It was found that the specific activity increased 3.6 times after ammonium sulphate precipitation and Sephadex G-100 Chromatography of crude extract. Lipase activity at different levels of ammonium sulphate showed lower activity. Fractions precipitated with 80% saturated ammonium sulphate has the maximum activity and no activity was detected in the filtrate from this fraction. Lipase was found to have optimum activity at temperature 45 degree C and at pH 7.0. The amino acid composition of the enzyme showed that lipase had high amount of polar amino acids than non polar amino acid content.