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Moncef Nasri - One of the best experts on this subject based on the ideXlab platform.
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Hepatoprotective and nephroprotective effects of sardinelle (Sardinella aurita) protein hydrolysate against ethanol-induced oxidative stress in rats.
Environmental science and pollution research international, 2016Co-Authors: Zeineb Kamoun, Moncef Nasri, Ali Bougatef, Alya Sellami Kamoun, Rim Marrakchi Kharrat, Houssem Youssfi, Tahia Boudawara, Mouna Chakroun, Najiba ZeghalAbstract:Ethanol consumption-induced oxidative stress that is a major etiological factor has been proven to play important roles in organs’ injury. In the present study, we investigated the protective effect of fish protein hydrolysate prepared from the heads and viscera of sardinelle (Sardinella aurita) (SPH) against the toxicity of ethanol on the liver and kidney of adult male rats. Animals were divided into four groups of six animals each: group C served as control, group Eth received 30 % ethanol solution at the dose of 3 g/kg body weight, group SPH received only 7.27 mg of SPH/kg body weight, and group Eth-SPH received ethanol and SPH simultaneously at the doses of 30 % and 7.27 mg/kg body weight, respectively. All groups were treated by gavage way for 15 days. Ethanol treatment decreased the defense enzymatic system including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), which increased after the co-administration of SPH. Malondialdehyde (MDA) and toxicity biomarker levels such as aspartate transaminase (AST) and alanine transaminase (ALT) and alcaline phosphatase (ALP) and gamma-glutamyl transaminase (GGT) activities were enhanced after chronic ethanol treatment and reduced by co-treatment with SPH. The histological examination of the liver and kidney confirmed biochemical changes in ethanol-treated rats and demonstrated the protective role of SPH.
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Composition, functional properties and in vitro antioxidant activity of protein hydrolysates prepared from sardinelle (Sardinella aurita) muscle
Journal of Food Science and Technology, 2014Co-Authors: Hayet Ben Khaled, Naourez Ktari, Olfa Ghorbel-bellaaj, Mourad Jridi, Imen Lassoued, Moncef NasriAbstract:Composition, functional properties and in vitro antioxidative activities of protein hydrolysates prepared from muscle of sardinelle ( Sardinella aurita ) were investigated. Sardinelle protein hydrolysates (SPH) were obtained by treatment with crude enzyme preparations from Bacillus pumilus A1 (SPHA1), Bacillus mojavensis A21 (SPHA21) and crude enzyme extract from sardinelle ( Sardinella aurita ) viscera (SPHEE). The protein hydrolysates SPHA1, SPHA21 and SPHEE contained high protein content 79.1%, 78.25% and 74.37%, respectively. The protein hydrolysates had an excellent solubility and possessed interfacial properties, which were governed by their concentrations. The antioxidant activities of protein hydrolysates at different concentrations were evaluated using various in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power assay, chelating activity, β-carotene bleaching and DNA nicking assay. All protein hydrolysates showed varying degrees of antioxidant activity. SPHA21 had the highest DPPH radical scavenging activity (89% at 6 mg/ml) and higher ability to prevent bleaching of β-carotene than SPHA1 and SPHEE ( p
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A heat-stable Cu/Zn superoxide dismutase from the viscera of sardinelle (Sardinella aurita): purification and biochemical characterization
Biologia, 2014Co-Authors: Hayet Ben Khaled, Naourez Ktari, Moncef Nasri, Noomen Hmidet, Rayda Siala, Ahmed Bayoudh, Sofiane GhorbelAbstract:Superoxide dismutase (SOD) is an enzyme that protects against oxidative stress from superoxide radicals in living cells. This enzyme was extracted from sardinelle (Sardinella aurita) viscera, purified and characterized. The Cu/Zn-SOD was purified to homogeneity by the three-step procedure consisting of the heating at 65°C for 15 min, precipitation with ammonium sulphate (30–60%, w/v) and Sephadex G-100 gel filtration with a 7.17-fold increase in specific activity. The molecular weight of the native enzyme was estimated to be 40 kDa by G-125 gel filtration on HPLC column and that of the subunit mass, deduced by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, was 20 kDa. Thus the native enzyme appeared to be a homodimer. The optimum pH and temperature for the purified SOD activity were determined to be pH 7.0 and 40°C, respectively. It retained more than 85% of its initial activity after 1 h of incubation at 50°C. The enzyme had a broad stability pH range of 6.0–9.0. The N-terminal sequence of the purified enzyme was VLKAVCVLKGTGEVT. This sequence exhibited a high degree of sequence similarity with other fish Cu/Zn SODs.
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Composition, functional properties and in vitro antioxidant activity of protein hydrolysates prepared from sardinelle (Sardinella aurita) muscle
Journal of food science and technology, 2011Co-Authors: Hayet Ben Khaled, Naourez Ktari, Olfa Ghorbel-bellaaj, Mourad Jridi, Imen Lassoued, Moncef NasriAbstract:Composition, functional properties and in vitro antioxidative activities of protein hydrolysates prepared from muscle of sardinelle (Sardinella aurita) were investigated. Sardinelle protein hydrolysates (SPH) were obtained by treatment with crude enzyme preparations from Bacillus pumilus A1 (SPHA1), Bacillus mojavensis A21 (SPHA21) and crude enzyme extract from sardinelle (Sardinella aurita) viscera (SPHEE). The protein hydrolysates SPHA1, SPHA21 and SPHEE contained high protein content 79.1%, 78.25% and 74.37%, respectively. The protein hydrolysates had an excellent solubility and possessed interfacial properties, which were governed by their concentrations. The antioxidant activities of protein hydrolysates at different concentrations were evaluated using various in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power assay, chelating activity, β-carotene bleaching and DNA nicking assay. All protein hydrolysates showed varying degrees of antioxidant activity. SPHA21 had the highest DPPH radical scavenging activity (89% at 6 mg/ml) and higher ability to prevent bleaching of β-carotene than SPHA1 and SPHEE (p < 0.05). However, SPHEE exhibited the highest metal chelating activity (89% at 1 mg/ml) and the strongest protection against hydroxyl radical induced DNA breakage (p < 0.05).
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A novel aspartic protease from the viscera of Sardinelle (Sardinella aurita): Purification and characterisation
Food Chemistry, 2011Co-Authors: Hayet Ben Khaled, Olfa Ghorbel-bellaaj, Noomen Hmidet, Kemel Jellouli, Nedra El-hadj Ali, Sofiane Ghorbel, Moncef NasriAbstract:Abstract A novel aspartic protease was extracted from the defatted viscera of sardinelle ( Sardinella aurita ) and purified, with a 9.5-fold increase in specific activity and 23.3% recovery. The molecular weight of the purified enzyme was estimated to be 17 kDa by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). The purified enzyme appeared as a single band on native-PAGE. The optimum pH and temperature for protease activity were around 3.0 and 40 °C, respectively. The enzyme showed pH stability between 2.0 and 5.0 and retained more than 50% of its activity after heating for 30 min at 50 °C. The enzyme lost 90% of its activity after incubation with pepstatin A at room temperature, but was not inhibited by soybean trypsin inhibitor or phenylmethylsulfonyl fluoride. Its K m value was determined to be 0.73 × 10 −4 M using haemoglobin as a substrate. The N-terminal 12 amino acid sequence of the purified acidic protease was R V I I E D X D Q F C T. This sequence showed low homology with aspartic peptidases of several other species of fish, suggesting that the enzyme is a new aspartic protease.
Jaime E. Valls - One of the best experts on this subject based on the ideXlab platform.
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CARACTERIZACIÓN FÍSICA Y QUÍMICA DE LA SARDINA (Sardinella aurita) Physical and Chemical Characterization of the Sardine (Sardinella aurita)
2010Co-Authors: Jaime E. Valls, Ana ParedesAbstract:El objetivo del presente estudio fue la evaluacion de los parametros fisicos y quimicos en sardinas (Sardinella aurita) recien capturadas, durante los meses de mayo, junio y julio. Los parametros evaluados fueron: analisis proximal (humedad, proteina, grasa y ceniza), hierro, calcio, fosforo, cloruros, mercurio, cadmio, plomo, pH, acido lactico (AL), bases volatiles totales (BVT), trimetilamina (TMA), solubilidad de proteinas en soluciones salinas (SPs), liquido exprimible (LE), color (L, a y b), degradacion de nucleotidos, valor K%, Hx/Ino, aminas biogenas y perfil de acidos grasos. Los resultados mas relevantes son los siguientes: el analisis proximal mostro diferencias significativas entre los meses evaluados (P 0,05) entre los meses. El valor K obtenido (12,05 a 24,12) y el bajo contenido de aminas biogenas son indicativos tambien de una materia prima con alto grado de frescura. El perfil de acidos grasos mostro una alta proporcion de acidos poliinsaturados (31,58 a 37,00%), especialmente de los acidos eicosapentaenoico (14,19 a 16,06%) y docosahexaenoico (12,00 a 15,80%), lo cual puede ser beneficioso para consumo humano y para la prevencion de algunas enfermedades. Todos los valores determinados (fisicos y quimicos) pueden ser considerados como representativos y tipicos para esta especie de sardina (Sardinella aurita) recien capturada, unido a una correcta manipulacion y almacenamiento en hielo.
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Physical and Chemical Characterization of the Sardine (Sardinella aurita)
2010Co-Authors: Jaime E. Valls, Ana ParedesAbstract:El objetivo del presente estudio fue la evaluacion de los parametros fisicos y quimicos en sardinas (Sardinella aurita) recien capturadas, durante los meses de mayo, junio y julio. Los parametros evaluados fueron: analisis proximal (humedad, proteina, grasa y ceniza), hierro, calcio, fosforo, cloruros, mercurio, cadmio, plomo, pH, acido lactico (AL), bases volatiles totales (BVT), trimetilamina (TMA), solubilidad de proteinas en soluciones salinas (SPs), liquido exprimible (LE), color (L, a y b), degradacion de nucleotidos, valor K%, Hx/Ino, aminas biogenas y perfil de acidos grasos. Los resultados mas relevantes son los siguientes: el analisis proximal mostro diferencias significativas entre los meses evaluados (P 0,05) entre los meses. El valor K obtenido (12,05 a 24,12) y el bajo contenido de aminas biogenas son indicativos tambien de una materia prima con alto grado de frescura. El perfil de acidos grasos mostro una alta proporcion de acidos poliinsaturados (31,58 a 37,00%), especialmente de los acidos eicosapentaenoico (14,19 a 16,06%) y docosahexaenoico (12,00 a 15,80%), lo cual puede ser beneficioso para consumo humano y para la prevencion de algunas enfermedades. Todos los valores determinados (fisicos y quimicos) pueden ser considerados como representativos y tipicos para esta especie de sardina (Sardinella aurita) recien capturada, unido a una correcta manipulacion y almacenamiento en hielo.
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caracterizacion fisica y quimica de la sardina Sardinella aurita
Revista Científica, 2010Co-Authors: Jaime E. Valls, Ana ParedesAbstract:El objetivo del presente estudio fue la evaluacion de los parametros fisicos y quimicos en sardinas (Sardinella aurita) recien capturadas, durante los meses de mayo, junio y julio. Los parametros evaluados fueron: analisis proximal (humedad, proteina, grasa y ceniza), hierro, calcio, fosforo, cloruros, mercurio, cadmio, plomo, pH, acido lactico (AL), bases volatiles totales (BVT), trimetilamina (TMA), solubilidad de proteinas en soluciones salinas (SPs), liquido exprimible (LE), color (L, a y b), degradacion de nucleotidos, valor K%, Hx/Ino, aminas biogenas y perfil de acidos grasos. Los resultados mas relevantes son los siguientes: el analisis proximal mostro diferencias significativas entre los meses evaluados (P 0,05) entre los meses. El valor K obtenido (12,05 a 24,12) y el bajo contenido de aminas biogenas son indicativos tambien de una materia prima con alto grado de frescura. El perfil de acidos grasos mostro una alta proporcion de acidos poliinsaturados (31,58 a 37,00%), especialmente de los acidos eicosapentaenoico (14,19 a 16,06%) y docosahexaenoico (12,00 a 15,80%), lo cual puede ser beneficioso para consumo humano y para la prevencion de algunas enfermedades. Todos los valores determinados (fisicos y quimicos) pueden ser considerados como representativos y tipicos para esta especie de sardina (Sardinella aurita) recien capturada, unido a una correcta manipulacion y almacenamiento en hielo.
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evaluacion fisica y quimica de la sardina Sardinella aurita durante su almacenamiento en hielo
2009Co-Authors: Alejandra B Delgado, Jaime E. Valls, Aníbal GonzálezAbstract:The present study evaluated the changes of physical and chemical parameters (pH, lactic acid, total volatile bases (TVB) and trimethylamine (TMA) in three lots: I (june), II (july) and III (November) of sardine (Sardinella aurita), subjected to refrigeration in isothermic box with ice (4o C) under two conditions: whole (WS) and eviscerated-behead (ES) for 20 days. The initial values of pH for the three lots varied between 5.8 - 6.3. Lots I and II registered a decrease during the initial time and then it increased to reach close initials values. While III the pH increase from first day. With regard to the content of lactic acid, for the three lots similar initial values were obtained (36-38 μmol/g) reaching different values to the end of the storage: 14-19 μmol/g, 21-26 and 2-3 for I, II and III lots respectively. In this experience the capture time and the storage conditions did not exercise influences in the variations of the pH and lactic acid (P>0.05). The measurements of TVB (mg N/100 g) and TMA (mg N/100 g) did not reflect to be good indicative of deterioration degree for none of the three lots, however their values were between acceptable freshness levels reported by the literature during the whole period of study.
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evaluacion de aminas biogenas microbiologica y sensorial de sardina Sardinella aurita durante su almacenamiento en hielo
2009Co-Authors: Alejandra B Delgado, Jaime E. Valls, Elisabetta TomeAbstract:The present study evaluated the changes of sensorial parameters, microbiological examinations (aerobic mesophiles, psychrotrophs and histamines-producers bacteria) and formation of biogenic amines in three lots: I (June), II (July) and III (November) of sardine (Sardinella aurita). Each lot was subjected to refrigeration in isothermic box with ice (4°C), under two conditions: whole (WS) and eviscerated-behaed (ES) for 20 days. The microbiological result show a low mesophilic initial count (103 UFC/g) in these lots, which increased until reaching final values of 105 UFC/g. While psychrophilic microorganisms began lo increase from sixth day of storage (103 UFC/g) and reached up lo 107 UFC/g at the end of study, for both conditions. The histamine-forming bacteria count were low, during all the experiences (≤ 10-103 UFC/g). The results of sensorial evaluation indicated a good freshness grade from the beginning until the second day of storage; between 3-13 days sardines conserved a good quality and later from 14 days until storage ended (20 d) they were considered with low quality. These stages were observed in both storage conditions, however better quality was determinate in eviscerated-behead. The sensorial evaluation was most suitable lo measure sardine freshness and stability.
Hayet Ben Khaled - One of the best experts on this subject based on the ideXlab platform.
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A heat-stable Cu/Zn superoxide dismutase from the viscera of sardinelle (Sardinella aurita): purification and biochemical characterization
Biologia, 2014Co-Authors: Hayet Ben Khaled, Naourez Ktari, Moncef Nasri, Noomen Hmidet, Rayda Siala, Ahmed Bayoudh, Sofiane GhorbelAbstract:Superoxide dismutase (SOD) is an enzyme that protects against oxidative stress from superoxide radicals in living cells. This enzyme was extracted from sardinelle (Sardinella aurita) viscera, purified and characterized. The Cu/Zn-SOD was purified to homogeneity by the three-step procedure consisting of the heating at 65°C for 15 min, precipitation with ammonium sulphate (30–60%, w/v) and Sephadex G-100 gel filtration with a 7.17-fold increase in specific activity. The molecular weight of the native enzyme was estimated to be 40 kDa by G-125 gel filtration on HPLC column and that of the subunit mass, deduced by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, was 20 kDa. Thus the native enzyme appeared to be a homodimer. The optimum pH and temperature for the purified SOD activity were determined to be pH 7.0 and 40°C, respectively. It retained more than 85% of its initial activity after 1 h of incubation at 50°C. The enzyme had a broad stability pH range of 6.0–9.0. The N-terminal sequence of the purified enzyme was VLKAVCVLKGTGEVT. This sequence exhibited a high degree of sequence similarity with other fish Cu/Zn SODs.
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Composition, functional properties and in vitro antioxidant activity of protein hydrolysates prepared from sardinelle (Sardinella aurita) muscle
Journal of food science and technology, 2011Co-Authors: Hayet Ben Khaled, Naourez Ktari, Olfa Ghorbel-bellaaj, Mourad Jridi, Imen Lassoued, Moncef NasriAbstract:Composition, functional properties and in vitro antioxidative activities of protein hydrolysates prepared from muscle of sardinelle (Sardinella aurita) were investigated. Sardinelle protein hydrolysates (SPH) were obtained by treatment with crude enzyme preparations from Bacillus pumilus A1 (SPHA1), Bacillus mojavensis A21 (SPHA21) and crude enzyme extract from sardinelle (Sardinella aurita) viscera (SPHEE). The protein hydrolysates SPHA1, SPHA21 and SPHEE contained high protein content 79.1%, 78.25% and 74.37%, respectively. The protein hydrolysates had an excellent solubility and possessed interfacial properties, which were governed by their concentrations. The antioxidant activities of protein hydrolysates at different concentrations were evaluated using various in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power assay, chelating activity, β-carotene bleaching and DNA nicking assay. All protein hydrolysates showed varying degrees of antioxidant activity. SPHA21 had the highest DPPH radical scavenging activity (89% at 6 mg/ml) and higher ability to prevent bleaching of β-carotene than SPHA1 and SPHEE (p < 0.05). However, SPHEE exhibited the highest metal chelating activity (89% at 1 mg/ml) and the strongest protection against hydroxyl radical induced DNA breakage (p < 0.05).
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A novel aspartic protease from the viscera of Sardinelle (Sardinella aurita): Purification and characterisation
Food Chemistry, 2011Co-Authors: Hayet Ben Khaled, Olfa Ghorbel-bellaaj, Noomen Hmidet, Kemel Jellouli, Nedra El-hadj Ali, Sofiane Ghorbel, Moncef NasriAbstract:Abstract A novel aspartic protease was extracted from the defatted viscera of sardinelle ( Sardinella aurita ) and purified, with a 9.5-fold increase in specific activity and 23.3% recovery. The molecular weight of the purified enzyme was estimated to be 17 kDa by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). The purified enzyme appeared as a single band on native-PAGE. The optimum pH and temperature for protease activity were around 3.0 and 40 °C, respectively. The enzyme showed pH stability between 2.0 and 5.0 and retained more than 50% of its activity after heating for 30 min at 50 °C. The enzyme lost 90% of its activity after incubation with pepstatin A at room temperature, but was not inhibited by soybean trypsin inhibitor or phenylmethylsulfonyl fluoride. Its K m value was determined to be 0.73 × 10 −4 M using haemoglobin as a substrate. The N-terminal 12 amino acid sequence of the purified acidic protease was R V I I E D X D Q F C T. This sequence showed low homology with aspartic peptidases of several other species of fish, suggesting that the enzyme is a new aspartic protease.
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Purification and characterization of three trypsin isoforms from viscera of sardinelle (Sardinella aurita)
Fish physiology and biochemistry, 2010Co-Authors: Hayet Ben Khaled, Nabil Souissi, Kemel Jellouli, Sofiane Ghorbel, Ahmed Barkia, Moncef NasriAbstract:Three trypsin isoforms A, B and C were purified to homogeneity from the viscera of sardinelle (Sardinella aurita). Purification was achieved by ammonium sulfate precipitation (20–70% (w/v)), Sephadex G-100 gel filtration and Mono Q-Sepharose anion-exchange chromatography. The molecular weights of these purified enzymes were estimated to be 28.8 kDa by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). Based on the native PAGE and casein-zymography, each purified trypsin appeared as a single band. Trypsins A and C exhibited the maximal activity at 55°C, while trypsin B at 50°C. All isoforms showed the same optimal pH (pH 9.0) using Nα-benzoyl-dl-arginine-p-nitroanilide (BAPNA) as a substrate. The three trypsins were stable at temperatures below 40°C and over a broad pH range (7.0–11.0). The activities of the three isoforms were strongly inhibited by soybean trypsin inhibitor and phenylmethylsulfonyl fluoride, a serine protease inhibitor, and partially inhibited by ethylenediaminetetraacetic acid, a metalloenzyme inhibitor. Kinetic constants of trypsins A, B and C for BAPNA were evaluated at 25°C and pH 9.0. The values of Km and kcat were 0.125, 0.083 and 0.10 mM, and 2.24, 1.21 and 5.76 s−1, respectively. The N-terminal sequences of the first 10 amino acids were “I V G G Y E C Q K Y” for trypsin A and “I V G G Y E A Q S Y” for trypsins B and C. These sequences showed highly homology to other fish trypsins.
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Isolation and characterisation of trypsin from sardinelle (Sardinella aurita) viscera
Journal of the Science of Food and Agriculture, 2008Co-Authors: Hayet Ben Khaled, Nabil Souissi, Ali Bougatef, Yosra Triki-ellouz, Rafik Balti, Moncef NasriAbstract:BACKGROUND: In Tunisia, sardinelle (Sardinella aurita) catches totalled about 13 300 t in 2002. During processing, solid wastes including heads and viscera are generated, representing about 30% of the original raw material. Viscera, one of the most important by-products of the fishing industry, are recognised as a potential source of digestive enzymes, especially proteases with high activity over a wide range of pH and temperature conditions. This paper describes the purification procedure and some biochemical characterisation of trypsin from S. aurita viscera. RESULTS: Trypsin from the viscera of sardinelle (S. aurita) was purified by fractionation with ammonium sulphate, Sephadex G-75 gel filtration, Sepharose mono Q anion exchange chromatography, ultrafiltration and a second Sephadex G-75 gel filtration, resulting in a 5.42-fold increase in specific activity and 6.1% recovery. The molecular weight of the purified enzyme was estimated to be 24 kDa using size exclusion chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified enzyme showed esterase-specific activity on N-α-benzoyl-L-arginine ethyl ester (BAEE) that was four times greater than its amidase-specific activity on N-α-benzoyl-DL-arginine-p-nitroanilide (BAPNA). The optimal pH and temperature for enzyme activity were pH 8 and 55 °C respectively using BAEE as a substrate. The trypsin kinetic constants Km and kcat on BAPNA were 1.67 mmol L−1 and 3.87 s−1 respectively, while the catalytic efficiency kcat/Km was 2.31 s−1 L mmol−1. CONCLUSION: Trypsin was purified from sardinelle (S. aurita) viscera. Biochemical characterisation of S. aurita trypsin showed that this enzyme can be used as a possible biotechnological tool in the fish-processing and food industries. Copyright © 2008 Society of Chemical Industry
Olfa Ghorbel-bellaaj - One of the best experts on this subject based on the ideXlab platform.
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Composition, functional properties and in vitro antioxidant activity of protein hydrolysates prepared from sardinelle (Sardinella aurita) muscle
Journal of Food Science and Technology, 2014Co-Authors: Hayet Ben Khaled, Naourez Ktari, Olfa Ghorbel-bellaaj, Mourad Jridi, Imen Lassoued, Moncef NasriAbstract:Composition, functional properties and in vitro antioxidative activities of protein hydrolysates prepared from muscle of sardinelle ( Sardinella aurita ) were investigated. Sardinelle protein hydrolysates (SPH) were obtained by treatment with crude enzyme preparations from Bacillus pumilus A1 (SPHA1), Bacillus mojavensis A21 (SPHA21) and crude enzyme extract from sardinelle ( Sardinella aurita ) viscera (SPHEE). The protein hydrolysates SPHA1, SPHA21 and SPHEE contained high protein content 79.1%, 78.25% and 74.37%, respectively. The protein hydrolysates had an excellent solubility and possessed interfacial properties, which were governed by their concentrations. The antioxidant activities of protein hydrolysates at different concentrations were evaluated using various in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power assay, chelating activity, β-carotene bleaching and DNA nicking assay. All protein hydrolysates showed varying degrees of antioxidant activity. SPHA21 had the highest DPPH radical scavenging activity (89% at 6 mg/ml) and higher ability to prevent bleaching of β-carotene than SPHA1 and SPHEE ( p
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Composition, functional properties and in vitro antioxidant activity of protein hydrolysates prepared from sardinelle (Sardinella aurita) muscle
Journal of food science and technology, 2011Co-Authors: Hayet Ben Khaled, Naourez Ktari, Olfa Ghorbel-bellaaj, Mourad Jridi, Imen Lassoued, Moncef NasriAbstract:Composition, functional properties and in vitro antioxidative activities of protein hydrolysates prepared from muscle of sardinelle (Sardinella aurita) were investigated. Sardinelle protein hydrolysates (SPH) were obtained by treatment with crude enzyme preparations from Bacillus pumilus A1 (SPHA1), Bacillus mojavensis A21 (SPHA21) and crude enzyme extract from sardinelle (Sardinella aurita) viscera (SPHEE). The protein hydrolysates SPHA1, SPHA21 and SPHEE contained high protein content 79.1%, 78.25% and 74.37%, respectively. The protein hydrolysates had an excellent solubility and possessed interfacial properties, which were governed by their concentrations. The antioxidant activities of protein hydrolysates at different concentrations were evaluated using various in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power assay, chelating activity, β-carotene bleaching and DNA nicking assay. All protein hydrolysates showed varying degrees of antioxidant activity. SPHA21 had the highest DPPH radical scavenging activity (89% at 6 mg/ml) and higher ability to prevent bleaching of β-carotene than SPHA1 and SPHEE (p < 0.05). However, SPHEE exhibited the highest metal chelating activity (89% at 1 mg/ml) and the strongest protection against hydroxyl radical induced DNA breakage (p < 0.05).
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A novel aspartic protease from the viscera of Sardinelle (Sardinella aurita): Purification and characterisation
Food Chemistry, 2011Co-Authors: Hayet Ben Khaled, Olfa Ghorbel-bellaaj, Noomen Hmidet, Kemel Jellouli, Nedra El-hadj Ali, Sofiane Ghorbel, Moncef NasriAbstract:Abstract A novel aspartic protease was extracted from the defatted viscera of sardinelle ( Sardinella aurita ) and purified, with a 9.5-fold increase in specific activity and 23.3% recovery. The molecular weight of the purified enzyme was estimated to be 17 kDa by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). The purified enzyme appeared as a single band on native-PAGE. The optimum pH and temperature for protease activity were around 3.0 and 40 °C, respectively. The enzyme showed pH stability between 2.0 and 5.0 and retained more than 50% of its activity after heating for 30 min at 50 °C. The enzyme lost 90% of its activity after incubation with pepstatin A at room temperature, but was not inhibited by soybean trypsin inhibitor or phenylmethylsulfonyl fluoride. Its K m value was determined to be 0.73 × 10 −4 M using haemoglobin as a substrate. The N-terminal 12 amino acid sequence of the purified acidic protease was R V I I E D X D Q F C T. This sequence showed low homology with aspartic peptidases of several other species of fish, suggesting that the enzyme is a new aspartic protease.
R. Guzman - One of the best experts on this subject based on the ideXlab platform.
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Unexpected reproductive strategy of Sardinella aurita off the coast of Venezuela
Marine Biology, 1997Co-Authors: Pierre Fréon, Jeremy Mendoza, M. El Khattabi, R. GuzmanAbstract:Biological sampling of Spanish sardine (Sardinella aurita Valenciennes, 1847) off the coast of Venezuela from 1956 to 1989 was used to study the reproductive strategy and migration pattern of the population. Whereas in many pelagic fishes the energy re-allocation necessary for reproduction usually occurs optimally at the end of the upwelling season when planktonic production reaches a maximum, in the present study a 5 mo delay was observed. This suggests that energy was stored as lipids early in the season and released later via metabolism for gamete production. Major reproduction did not occur in an area and at a time when offshore transport and turbulence were low, which is also unusual for a pelagic fish species. These results are discussed in terms of the life cycle of the Spanish sardine and its possible migratory patterns. The reproductive strategy of this population apparently gives priority to optimising food availability for the offspring and not to preventing eggs and larvae being transported offshore. The presence of “retention” areas could explain this unexpected strategy.
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VPA estimates of fishing mortality and exploited biomass from Sardinella aurita catch-at-length data in eastern Venezuela
1994Co-Authors: Jeremy Mendoza, Pierre Fréon, R. GuzmanAbstract:In this study, length-frequency data on Spanish sardine (Sardinella aurita) from northeastern Venezuela were analyzed for the period 1967-1989. Average growth parameters for the von Bertalanffy equation were established as L sub( infinity )= 26.6 cm (TL) and K = 1.26 year super(-1). The number of recruits to the fishing area, estimated from length-structured Virtual Population Analysis, varied from 10 super(9) at the end of the 1980s. Exploited biomass estimates for the same period varied from less than 20,000 t in the first year to more than 100,000 in 1989. Both recruitment and exploited biomass showed different seasonal patterns between 1976-1983 and 1984-1988. Despite some uncertainty regarding these estimates, it is considered that major population tendencies are adequately represented by this analysis