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Papers
Journal of The Science of Food and Agriculture , 2003
Alkaline phosphatase (EC 3.1.3.1) extracted from Escherichia coli ATCC27257 was immobilised by co... more Alkaline phosphatase (EC 3.1.3.1) extracted from Escherichia coli ATCC27257 was immobilised by co-flocculation with soil humates in the presence of Ca2+. The effects of time, temperature, pH and concentration of enzyme and support on immobilisation were studied. Between 58 and 92% of the added phosphatase was strongly bound to the humates, depending on the conditions of immobilisation used. Some characteristics of the humate–phosphatase complexes and of the free enzyme were compared. The enzymatic complexes showed values of Km (2.22 mM) and activation energy (33.4 kJ mol−1) similar to those of the free enzyme (2.00 mM and 27.6 kJ mol−1). The pH/activity profiles revealed no change in terms of shape or optimum pH (10.5) upon immobilisation of alkaline phosphatase. However, the immobilised enzyme showed maximal activity in the range of 80–100 °C, while the free enzyme had its highest activity at 60 °C. The thermal stability of alkaline phosphatase was enhanced by complexation to the soil humates.© 2003 Society of Chemical Industry
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Food Chemistry , 2008
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Journal of Biotechnology , 2007
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International Journal of Food Science and Technology , 2004
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International Biodeterioration & Biodegradation , 2001
In order to optimize the enzymatic hydrolysis of three celluloses (carboxymethyl cellulose, powde... more In order to optimize the enzymatic hydrolysis of three celluloses (carboxymethyl cellulose, powdered cellulose and microgranular cellulose), the effect of varying enzyme and substrate concentration, temperature and pH was studied. The best experimental conditions found ...
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International Dairy Journal , 2007
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Journal of Chemical Technology and Biotechnology , 2004
Fractional factorial screening design and response surface methodology were applied to optimize t... more Fractional factorial screening design and response surface methodology were applied to optimize the entrapment of glucose oxidase in liposomes by the dehydration–rehydration vesicle (DRV) method. Phosphatidylcholine from different sources, cholesterol:phosphatidylcholine (Ch:PC) and enzyme:lipid (E:L) ratios, buffer pH, sonication frequency and trehalose concentration were the parameters selected for this study. The type of phosphatidylcholine was found to be the most important factor followed by the trehalose concentration, Ch:PC ratio, sonication frequency and E:L ratio. The pH did not play an important role in the response. By treating liposomes with trehalose, as cryoprotectant, the activity of entrapped enzyme decreased by 16%. Two of the factors (cholesterol:phosphatidylcholine and enzyme:lipid ratios) were further studied in a 32 central composite design. The optimized liposomal formulation with an entrapment efficiency of 24% was obtained for egg yolk PC with Ch:PC and E:L ratios of 0.95 and 14.69, respectively, at pH 6 and applying a sonication frequency of 150 W. Copyright © 2004 Society of Chemical Industry
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Biocatalysis and Biotransformation , 2000
... NATIVIDAD ORTEGA, MARIA D. BUST0 and MANUEL PEREZ-MATEOS* ... dilution with 0.1 N sodium acet... more ... NATIVIDAD ORTEGA, MARIA D. BUST0 and MANUEL PEREZ-MATEOS* ... dilution with 0.1 N sodium acetate buffer) using the Somogyi-Nelson method (Nelson, 1944) and the glucose content was assayed after the glucose-oxidase method (Raabo and Terkildsen, 1960). ...
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Food Chemistry , 2007
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Journal of The Science of Food and Agriculture , 2010
BACKGROUND: This study was designed to evaluate and compare antioxidant capacity and radical scav... more BACKGROUND: This study was designed to evaluate and compare antioxidant capacity and radical scavenging activity of naringin and its aglycone by different in vitro assays. The effects of flavanones on lipid peroxidation, glutathione (GSH) oxidation and DNA cleavage were also assessed.RESULTS: The results showed that naringenin exhibited higher antioxidant capacity and hydroxyl and superoxide radical scavenger efficiency than naringin. Our results evidenced that glycosylation attenuated the efficiency in inhibiting the enzyme xanthine oxidase and the aglycone could act like a more active chelator of metallic ions than the glycoside. Additionally, naringenin showed a greater effectiveness in the protection against oxidative damage to lipids in a dose-dependent manner. Both flavanones were equally effective in reducing DNA damage. However, they show no protective effect on oxidation of GSH.CONCLUSION: The data obtained support the importance of characterizing the ratio naringin/naringenin in foods when they are evaluated for their health benefits. Copyright © 2010 Society of Chemical Industry
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Computers & Operations Research , 2007
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This paper deals with the assembly line balancing problem considering incompatibilities between t... more This paper deals with the assembly line balancing problem considering incompatibilities between the tasks with the aim of: first minimizing the number of workstations, and then minimizing the cycle time for the minimum number of workstations. In order to solve the problem we propose the use of a greedy randomized adaptive search procedure obtained from the application of some classic heuristics based on priority rules, and a genetic algorithm that searches for the solution in the heuristic space. A computational experience is included to illustrate the performance of the proposed approach
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Journal of The Science of Food and Agriculture , 2003
Alkaline phosphatase (EC 3.1.3.1) extracted from Escherichia coli ATCC27257 was immobilised by co... more Alkaline phosphatase (EC 3.1.3.1) extracted from Escherichia coli ATCC27257 was immobilised by co-flocculation with soil humates in the presence of Ca2+. The effects of time, temperature, pH and concentration of enzyme and support on immobilisation were studied. Between 58 and 92% of the added phosphatase was strongly bound to the humates, depending on the conditions of immobilisation used. Some characteristics of the humate–phosphatase complexes and of the free enzyme were compared. The enzymatic complexes showed values of Km (2.22 mM) and activation energy (33.4 kJ mol−1) similar to those of the free enzyme (2.00 mM and 27.6 kJ mol−1). The pH/activity profiles revealed no change in terms of shape or optimum pH (10.5) upon immobilisation of alkaline phosphatase. However, the immobilised enzyme showed maximal activity in the range of 80–100 °C, while the free enzyme had its highest activity at 60 °C. The thermal stability of alkaline phosphatase was enhanced by complexation to the soil humates.© 2003 Society of Chemical Industry
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Food Chemistry , 2008
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Journal of Biotechnology , 2007
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International Journal of Food Science and Technology , 2004
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International Biodeterioration & Biodegradation , 2001
In order to optimize the enzymatic hydrolysis of three celluloses (carboxymethyl cellulose, powde... more In order to optimize the enzymatic hydrolysis of three celluloses (carboxymethyl cellulose, powdered cellulose and microgranular cellulose), the effect of varying enzyme and substrate concentration, temperature and pH was studied. The best experimental conditions found ...
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International Dairy Journal , 2007
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Journal of Chemical Technology and Biotechnology , 2004
Fractional factorial screening design and response surface methodology were applied to optimize t... more Fractional factorial screening design and response surface methodology were applied to optimize the entrapment of glucose oxidase in liposomes by the dehydration–rehydration vesicle (DRV) method. Phosphatidylcholine from different sources, cholesterol:phosphatidylcholine (Ch:PC) and enzyme:lipid (E:L) ratios, buffer pH, sonication frequency and trehalose concentration were the parameters selected for this study. The type of phosphatidylcholine was found to be the most important factor followed by the trehalose concentration, Ch:PC ratio, sonication frequency and E:L ratio. The pH did not play an important role in the response. By treating liposomes with trehalose, as cryoprotectant, the activity of entrapped enzyme decreased by 16%. Two of the factors (cholesterol:phosphatidylcholine and enzyme:lipid ratios) were further studied in a 32 central composite design. The optimized liposomal formulation with an entrapment efficiency of 24% was obtained for egg yolk PC with Ch:PC and E:L ratios of 0.95 and 14.69, respectively, at pH 6 and applying a sonication frequency of 150 W. Copyright © 2004 Society of Chemical Industry
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Biocatalysis and Biotransformation , 2000
... NATIVIDAD ORTEGA, MARIA D. BUST0 and MANUEL PEREZ-MATEOS* ... dilution with 0.1 N sodium acet... more ... NATIVIDAD ORTEGA, MARIA D. BUST0 and MANUEL PEREZ-MATEOS* ... dilution with 0.1 N sodium acetate buffer) using the Somogyi-Nelson method (Nelson, 1944) and the glucose content was assayed after the glucose-oxidase method (Raabo and Terkildsen, 1960). ...
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Food Chemistry , 2007
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Journal of The Science of Food and Agriculture , 2010
BACKGROUND: This study was designed to evaluate and compare antioxidant capacity and radical scav... more BACKGROUND: This study was designed to evaluate and compare antioxidant capacity and radical scavenging activity of naringin and its aglycone by different in vitro assays. The effects of flavanones on lipid peroxidation, glutathione (GSH) oxidation and DNA cleavage were also assessed.RESULTS: The results showed that naringenin exhibited higher antioxidant capacity and hydroxyl and superoxide radical scavenger efficiency than naringin. Our results evidenced that glycosylation attenuated the efficiency in inhibiting the enzyme xanthine oxidase and the aglycone could act like a more active chelator of metallic ions than the glycoside. Additionally, naringenin showed a greater effectiveness in the protection against oxidative damage to lipids in a dose-dependent manner. Both flavanones were equally effective in reducing DNA damage. However, they show no protective effect on oxidation of GSH.CONCLUSION: The data obtained support the importance of characterizing the ratio naringin/naringenin in foods when they are evaluated for their health benefits. Copyright © 2010 Society of Chemical Industry
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Computers & Operations Research , 2007
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This paper deals with the assembly line balancing problem considering incompatibilities between t... more This paper deals with the assembly line balancing problem considering incompatibilities between the tasks with the aim of: first minimizing the number of workstations, and then minimizing the cycle time for the minimum number of workstations. In order to solve the problem we propose the use of a greedy randomized adaptive search procedure obtained from the application of some classic heuristics based on priority rules, and a genetic algorithm that searches for the solution in the heuristic space. A computational experience is included to illustrate the performance of the proposed approach
Bookmarks Related papers Mentions View impact
Bookmarks Related papers Mentions View impact
Bookmarks Related papers Mentions View impact
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