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Nadia Innocente - One of the best experts on this subject based on the ideXlab platform.
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hplc profile and dynamic surface properties of the Proteose peptone fraction from bovine milk and from whey protein concentrate
International Dairy Journal, 2011Co-Authors: Nadia Innocente, Marialuisa Biasutti, Christophe BleckerAbstract:Abstract Extraction of Proteose–Peptones (PPs) was carried out from fresh milk, from milk after prolonged incubation (12 days at 37 °C) and from two different whey protein concentrates (WPCs). The high performance liquid chromatography profiles of these extracts were compared. PPs eluted as three chromatographic peaks, which increased during milk incubation. The PP extracts from WPCs showed a number of peaks that are attributable to small peptides belonging to the Proteose–peptone fraction and probably derive from proteolysis during storage of WPC. The dynamic properties at the air–water interface of the PP extracts were investigated by the drop-volume method. The PPs extracted from fresh milk showed the lowest values and a more rapid reduction in surface tension. PPs from WPCs were found to be effective as surfactants, even though a less marked reduction in surface tension compared with PPs from milk samples was shown.
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Aroma retention capacity of different whey protein concentrates.
Milchwissenschaft-milk Science International, 2009Co-Authors: Nadia Innocente, Marialuisa Biasutti, G. MarchesiniAbstract:Some commercial whey protein concentrates (WPCs) were analyzed in order to determine the composition and relative content of the various whey protein fractions. The retention capacity of a homologous series of ester compounds (ethyl acetate, isoamyl acetate and ethyl hexanoate) was investigated in model systems and the data were also compared with those measured in the presence of β-lactoglobulin. The flavour/matrix interactions were studied using headspace solid-phase microextraction combined with gas-chromatography (HS-SPME-GC). The results showed that the WPCs considered differed in terms of protein, fat and lactose content. Moreover, the WPCs were also different as regards the relative content of single whey protein fractions (β-lactoglobulin, α-lactalbumin, immunoglobulins, Proteose-Peptones). These differences had a great effect on the aroma retention capacity. The WPCs showed aroma retention properties only for more hydrophobic ester compounds. The higher retention value for ethyl hexanoate measured in one of the WPCs was probably due to the higher fat content in this sample. Finally, no statistically significant retention property was found in the WPC sample that has been modified by thermal denaturation during manufacture to improve gelling properties.
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Proteose-peptone whey fraction as emulsifier in ice-cream preparation
International Dairy Journal, 2002Co-Authors: Nadia Innocente, D. Comparin, C. CorradiniAbstract:In the light of the results obtained from previous studies, which demonstrated the potential emulsifying and foaming capabilities of the Proteose-peptone fraction of milk, the efficacy of the functional properties of these protein components when used as ingredients in ice-cream preparation was studied. In order to compare the characteristics of ice-cream obtained from mixes containing added Proteose-Peptones with those of ice-cream produced without emulsifiers or with the addition of mono and diglycerides of fatty acids, analyses were conducted to evaluate the viscosity, the amount of incorporated air, the resistance to melting, as well as sensory characteristics. In every case, the ice-cream containing Proteose-Peptones as functional ingredients, exhibited similar if not better characteristics compared to those of the ice-cream containing classical commercial emulsifiers. As regards rheological properties, the experimental ice-cream mix with added Proteose-Peptones had a moderately higher consistency index compared to the commercial mix with mono and diglycerides. Finally, no effect of the Proteose-Peptones fraction on ice-cream flavour was observed.
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emulsifying properties of the total fraction and the hydrophobic fraction of bovine milk Proteose Peptones
International Dairy Journal, 1998Co-Authors: Nadia Innocente, Christophe Blecker, C. Corradini, Michel PaquotAbstract:Since Proteose-peptone is a mixture of heterogeneous proteins and peptides, its functional properties have not yet been fully understood. The present study was undertaken to elucidate the emulsifying properties of Proteose-Peptones and a parallel evaluation was performed of the emulsifying activity of the total fraction prepared from bulk skimmed milk by precipitation with ammonium sulphate and of the most hydrophobic fraction purified by hydrophobic interaction fast protein liquid chromatography. A turbidimetric technique was used and the absorbance value at 500 nm was then directly used as the emulsifying activity index. The results obtained confirmed the good emulsifying activity of this protein fraction of the whey and demonstrated the considerable influence of the concentration on the capacity of the Proteose-Peptones to stabilize a model oil-in-water emulsion. Moreover, at all the concentrations examined, the purified component 3 showed a higher emulsifying activity than the total unpurified fraction.
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Dynamic Surface Properties of the Proteose-Peptone Fraction of Bovine Milk
Journal of Dairy Science, 1998Co-Authors: Nadia Innocente, Cesare Corradini, Christophe Blecker, Michel PaquotAbstract:Proteose-peptone is a heat-stable and acid-soluble protein fraction of milk that has important functional properties. Component 3, which is the most hydrophobic fraction, appears to be largely responsible for the physicochemical properties of Proteose-Peptones and for their important biological role in milk. In this study, total Proteose-peptone was prepared from bulk skim milk by precipitation with ammonium sulfate, and the hydrophobic fraction was purified by FPLC® (Pharmacia Fine Chemicals, Uppsala, Sweden). The drop volume method was used to investigate the dynamic surface activity of total Proteose-peptone and component 3 of Proteose-peptone at the air-water interface and at the oil-water interface. In general, Proteose-Peptones are good surfactants at both interfaces. Of all Proteose-Peptones, component 3 causes a more rapid reduction of interfacial tension in both interfaces. A system for measuring film balance was used to obtain more information about the surface and mechanical properties of Proteose-peptone monolayers. We deduced from the compression isotherms that component 3 of Proteose-peptone and total Proteose-peptone films spread at the air-water interface present different mechanical properties.
Laurent François - One of the best experts on this subject based on the ideXlab platform.
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Mécanismes de la protéolyse dans le lait lors de l'inflammation de la glande mammaire chez la vache laitière (activité des protéases leucocytaires et des protéases bactériennes (cas d'Escherichia coli))
2006Co-Authors: Haddadi Kahina, Laurent FrançoisAbstract:La mammite est la pathologie la plus fréquente chez la vache laitière, affectant toute la filière laitière du producteur jusqu'au transformateur. L'objectif de ce travail est l'étude de l'incidence des facteurs endogènes (cellules somatiques, système plasmine-plasminogène) et des facteurs exogènes (bactéries) sur la caséinolyse. Ceci a été rendu possible grâce à des modèles expérimentaux de mammite in vivo à E. coli ou à LPS, et au modèle in vitro d'inoculation d'E. coli dans du lait cru. La protéolyse dans le modèle in vivo à E. coli a permis d'établir une séquentialité de protéolyse où les cellules somatiques et les bactéries interviendraient entre 3 et 216 h PI, et une phase entre 15 et 33 h PI où la plasmine serait prédominante. Plusieurs fractions peptidiques appartenant à la fraction protéose Peptones, sont présentes pendant la phase aigue de l'inflammation, dont deux peptides d'origine cellulaire. Dans ce modèle le rôle bactérien dans les mécanismes de la protéolyse est difficilement appréhendable. L'étude in vitro de la protéolyse d'origine bactérienne avec le modèle E. coli/lait a montré une interaction entre les bactéries, les protéases bactériennes et le système plasmine-plasminogène. Le second modèle in vitro protéases d'E. coli/caséines a quant à lui permis d'établir un ordre préférentiel de dégradation des caséines. Le modèle in vivo à LPS a montré que l'activité de la gélatinase dans la fraction constituée de cellules matures est plus importante que dans la fraction constituée de cellules immaturesMastitis is a frequently occurring pathological condition that is widely reported in dairy cow, affecting the whole field. The aim of this work is to investigate the endogenous proteolysis that includes mostly proteases of leukocytes and plasmin-plasminogen system in comparison with exogenous bacterial incidence on proteolysis of casein. The result of this study was possible owing to the feasibility of in vivo experimental mastitis using E. coli or endotoxin from E. coli and in vitro inoculation of E. coli strain in raw milk. Proteolysis in E. coli in vivo model enabled proteolysis sequentiality to be achieved. Both somatic cell count and bacteria were involved. Between 3 and 216 h PI; from 15 to 33 h PI the plasmin role was preponderant. During inflammation, many peptide fractions including two of cellular origin were present in the Proteose-Peptones fraction. The role of E. coli in milk proteolysis, however remains to be elucidated. In vitro study of bacterial proteolysis with E. coli / milk model demonstrated an interaction between bacteria, bacterial proteases and the plasmin-plasminogen system. The second model involving E. coli proteases/casein highlighted a preferential order of caseinolysis. Furthermore, LPS experimental mastitis showed that the gelatinase activity associated with mature blood PMN is more notable than in the immature blood PMNNANCY/VANDOEUVRE-INPL (545472102) / SudocSudocFranceF
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Protéolyse et redistribution des protéines entre différentes fractions azotées après traitement du lait par hautes pressions
2004Co-Authors: Nabhan, Mohamad Ammar, Laurent FrançoisAbstract:Les traitements thermiques induisent souvent des modifications indésirables dans les aliments qui pourraient être évitées par l'adoption de stratégies de traitement minimum du produit. Parmi ces traitements, les hautes pressions sont une technique déjà commercialisées à petite échelle par l'industrie alimentaire. La combinaison pression/température induit la dénaturation de la beta-lactogiobuline et entraîne la formation d'agrégats composés principalement de beta-lactogiobuline, de kappa-caséine et d'alpha-lactalbumine et minoritairement d'alphas1-caséine. Le traitement diminue l'activité plasminique et induire un déplissement irréversible d'alpha-lactalbumine à pH 7 et une quantité importante se trouve dans la fraction protéose- Peptones. Pour assurer la stabilité de la microflore naturelle du lait pendant 21 jours, le lait doit être traité au moins à 400 1 MPa et à des températures relativement extrêmes. Pour éliminer complètement les germes pathogènes et assurer une absence de survie pendant un stockage de 21 jours, un traitement d'au moins 500 MPa et 55ʿC pendant 5 est nécessaire. Le lait pressurisé présente une odeur, un goût, une couleur et une texture différents du lait pasteurisé et aucune préférence, pour un lait, n'est enregistrée.The thermal treatments induce frequently undesirable modifications in foods that could be avoided by the use of minimum treatment strategies. Among these treatments, high pressures are already commercialized by the alimentary industry. Pressure/temperature combination induced denaturation of beta-lactogiobulin and the formation of aggregates composed principally of beta-lactogiobulin, kappa-casein and of aipha-lactaibumin and of alphas1-casein at a lesser extent. The treatment reduce plasmin activity and induce an irreversible unfolding of aipha-lactaibumin at pH 7.0 and a significant quantity was recovered in Proteose-Peptones fraction. To ensure the stability of natural microflora of milk during 21 days, milk must be treated at least 400 MPa and at comparatively extreme temperature. To eliminate completely the studied pathogen bacteria and ensure no surviving during 21 days, a treatment of at least 500 MPa and 55ʿC for 5 min minimum is necessary. Our results show that pressurized milks present an odor, a taste, a color and a texture different of pasteurized milk. Although different, the jury do not mark preference to any milk tested.NANCY/VANDOEUVRE-INPL (545472102) / SudocSudocFranceF
Michel Paquot - One of the best experts on this subject based on the ideXlab platform.
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emulsifying properties of the total fraction and the hydrophobic fraction of bovine milk Proteose Peptones
International Dairy Journal, 1998Co-Authors: Nadia Innocente, Christophe Blecker, C. Corradini, Michel PaquotAbstract:Since Proteose-peptone is a mixture of heterogeneous proteins and peptides, its functional properties have not yet been fully understood. The present study was undertaken to elucidate the emulsifying properties of Proteose-Peptones and a parallel evaluation was performed of the emulsifying activity of the total fraction prepared from bulk skimmed milk by precipitation with ammonium sulphate and of the most hydrophobic fraction purified by hydrophobic interaction fast protein liquid chromatography. A turbidimetric technique was used and the absorbance value at 500 nm was then directly used as the emulsifying activity index. The results obtained confirmed the good emulsifying activity of this protein fraction of the whey and demonstrated the considerable influence of the concentration on the capacity of the Proteose-Peptones to stabilize a model oil-in-water emulsion. Moreover, at all the concentrations examined, the purified component 3 showed a higher emulsifying activity than the total unpurified fraction.
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Dynamic Surface Properties of the Proteose-Peptone Fraction of Bovine Milk
Journal of Dairy Science, 1998Co-Authors: Nadia Innocente, Cesare Corradini, Christophe Blecker, Michel PaquotAbstract:Proteose-peptone is a heat-stable and acid-soluble protein fraction of milk that has important functional properties. Component 3, which is the most hydrophobic fraction, appears to be largely responsible for the physicochemical properties of Proteose-Peptones and for their important biological role in milk. In this study, total Proteose-peptone was prepared from bulk skim milk by precipitation with ammonium sulfate, and the hydrophobic fraction was purified by FPLC® (Pharmacia Fine Chemicals, Uppsala, Sweden). The drop volume method was used to investigate the dynamic surface activity of total Proteose-peptone and component 3 of Proteose-peptone at the air-water interface and at the oil-water interface. In general, Proteose-Peptones are good surfactants at both interfaces. Of all Proteose-Peptones, component 3 causes a more rapid reduction of interfacial tension in both interfaces. A system for measuring film balance was used to obtain more information about the surface and mechanical properties of Proteose-peptone monolayers. We deduced from the compression isotherms that component 3 of Proteose-peptone and total Proteose-peptone films spread at the air-water interface present different mechanical properties.
Haddadi Kahina - One of the best experts on this subject based on the ideXlab platform.
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Mécanismes de la protéolyse dans le lait lors de l'inflammation de la glande mammaire chez la vache laitière : activité des protéases leucocytaires et des protéases bactériennes (cas d'Escherichia coli)
HAL CCSD, 2006Co-Authors: Haddadi KahinaAbstract:Mastitis is a frequently occurring pathological condition that is widely reported in dairy cow, affecting the whole field. The aim of this work is to investigate the endogenous proteolysis that includes mostly proteases of leukocytes and plasmin-plasminogen system in comparison with exogenous bacterial incidence on proteolysis of casein. The result of this study was possible owing to the feasibility of in vivo experimental mastitis using E. coli or endotoxin from E. coli and in vitro inoculation of E. coli strain in raw milk. Proteolysis in E. coli in vivo model enabled proteolysis sequentiality to be achieved. Both somatic cell count and bacteria were involved. Between 3 and 216 h PI; from 15 to 33 h PI the plasmin role was preponderant. During inflammation, many peptide fractions including two of cellular origin were present in the Proteose-Peptones fraction. The role of E. coli in milk proteolysis, however remains to be elucidated. In vitro study of bacterial proteolysis with E. coli / milk model demonstrated an interaction between bacteria, bacterial proteases and the plasmin-plasminogen system. The second model involving E. coli proteases/casein highlighted a preferential order of caseinolysis. Furthermore, LPS experimental mastitis showed that the gelatinase activity associated with mature blood PMN is more notable than in the immature blood PMNLa mammite est la pathologie la plus fréquente chez la vache laitière, affectant toute la filière laitière du producteur jusqu'au transformateur. L'objectif de ce travail est l'étude de l'incidence des facteurs endogènes (cellules somatiques, système plasmine-plasminogène) et des facteurs exogènes (bactéries) sur la caséinolyse. Ceci a été rendu possible grâce à des modèles expérimentaux de mammite in vivo à E. coli ou à LPS, et au modèle in vitro d'inoculation d'E. coli dans du lait cru. La protéolyse dans le modèle in vivo à E. coli a permis d'établir une séquentialité de protéolyse où les cellules somatiques et les bactéries interviendraient entre 3 et 216 h PI, et une phase entre 15 et 33 h PI où la plasmine serait prédominante. Plusieurs fractions peptidiques appartenant à la fraction protéose Peptones, sont présentes pendant la phase aiguë de l'inflammation, dont deux peptides d'origine cellulaire. Dans ce modèle le rôle bactérien dans les mécanismes de la protéolyse est difficilement appréhendable. L'étude in vitro de la protéolyse d'origine bactérienne avec le modèle E. coli/lait a montré une interaction entre les bactéries, les protéases bactériennes et le système plasmine-plasminogène. Le second modèle in vitro protéases d'E. coli/caséines a quant à lui permis d'établir un ordre préférentiel de dégradation des caséines. Le modèle in vivo à LPS a montré que l'activité de la gélatinase dans la fraction constituée de cellules matures est plus importante que dans la fraction constituée de cellules immature
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Mécanismes de la protéolyse dans le lait lors de l'inflammation de la glande mammaire chez la vache laitière (activité des protéases leucocytaires et des protéases bactériennes (cas d'Escherichia coli))
2006Co-Authors: Haddadi Kahina, Laurent FrançoisAbstract:La mammite est la pathologie la plus fréquente chez la vache laitière, affectant toute la filière laitière du producteur jusqu'au transformateur. L'objectif de ce travail est l'étude de l'incidence des facteurs endogènes (cellules somatiques, système plasmine-plasminogène) et des facteurs exogènes (bactéries) sur la caséinolyse. Ceci a été rendu possible grâce à des modèles expérimentaux de mammite in vivo à E. coli ou à LPS, et au modèle in vitro d'inoculation d'E. coli dans du lait cru. La protéolyse dans le modèle in vivo à E. coli a permis d'établir une séquentialité de protéolyse où les cellules somatiques et les bactéries interviendraient entre 3 et 216 h PI, et une phase entre 15 et 33 h PI où la plasmine serait prédominante. Plusieurs fractions peptidiques appartenant à la fraction protéose Peptones, sont présentes pendant la phase aigue de l'inflammation, dont deux peptides d'origine cellulaire. Dans ce modèle le rôle bactérien dans les mécanismes de la protéolyse est difficilement appréhendable. L'étude in vitro de la protéolyse d'origine bactérienne avec le modèle E. coli/lait a montré une interaction entre les bactéries, les protéases bactériennes et le système plasmine-plasminogène. Le second modèle in vitro protéases d'E. coli/caséines a quant à lui permis d'établir un ordre préférentiel de dégradation des caséines. Le modèle in vivo à LPS a montré que l'activité de la gélatinase dans la fraction constituée de cellules matures est plus importante que dans la fraction constituée de cellules immaturesMastitis is a frequently occurring pathological condition that is widely reported in dairy cow, affecting the whole field. The aim of this work is to investigate the endogenous proteolysis that includes mostly proteases of leukocytes and plasmin-plasminogen system in comparison with exogenous bacterial incidence on proteolysis of casein. The result of this study was possible owing to the feasibility of in vivo experimental mastitis using E. coli or endotoxin from E. coli and in vitro inoculation of E. coli strain in raw milk. Proteolysis in E. coli in vivo model enabled proteolysis sequentiality to be achieved. Both somatic cell count and bacteria were involved. Between 3 and 216 h PI; from 15 to 33 h PI the plasmin role was preponderant. During inflammation, many peptide fractions including two of cellular origin were present in the Proteose-Peptones fraction. The role of E. coli in milk proteolysis, however remains to be elucidated. In vitro study of bacterial proteolysis with E. coli / milk model demonstrated an interaction between bacteria, bacterial proteases and the plasmin-plasminogen system. The second model involving E. coli proteases/casein highlighted a preferential order of caseinolysis. Furthermore, LPS experimental mastitis showed that the gelatinase activity associated with mature blood PMN is more notable than in the immature blood PMNNANCY/VANDOEUVRE-INPL (545472102) / SudocSudocFranceF
Christophe Blecker - One of the best experts on this subject based on the ideXlab platform.
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hplc profile and dynamic surface properties of the Proteose peptone fraction from bovine milk and from whey protein concentrate
International Dairy Journal, 2011Co-Authors: Nadia Innocente, Marialuisa Biasutti, Christophe BleckerAbstract:Abstract Extraction of Proteose–Peptones (PPs) was carried out from fresh milk, from milk after prolonged incubation (12 days at 37 °C) and from two different whey protein concentrates (WPCs). The high performance liquid chromatography profiles of these extracts were compared. PPs eluted as three chromatographic peaks, which increased during milk incubation. The PP extracts from WPCs showed a number of peaks that are attributable to small peptides belonging to the Proteose–peptone fraction and probably derive from proteolysis during storage of WPC. The dynamic properties at the air–water interface of the PP extracts were investigated by the drop-volume method. The PPs extracted from fresh milk showed the lowest values and a more rapid reduction in surface tension. PPs from WPCs were found to be effective as surfactants, even though a less marked reduction in surface tension compared with PPs from milk samples was shown.
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emulsifying properties of the total fraction and the hydrophobic fraction of bovine milk Proteose Peptones
International Dairy Journal, 1998Co-Authors: Nadia Innocente, Christophe Blecker, C. Corradini, Michel PaquotAbstract:Since Proteose-peptone is a mixture of heterogeneous proteins and peptides, its functional properties have not yet been fully understood. The present study was undertaken to elucidate the emulsifying properties of Proteose-Peptones and a parallel evaluation was performed of the emulsifying activity of the total fraction prepared from bulk skimmed milk by precipitation with ammonium sulphate and of the most hydrophobic fraction purified by hydrophobic interaction fast protein liquid chromatography. A turbidimetric technique was used and the absorbance value at 500 nm was then directly used as the emulsifying activity index. The results obtained confirmed the good emulsifying activity of this protein fraction of the whey and demonstrated the considerable influence of the concentration on the capacity of the Proteose-Peptones to stabilize a model oil-in-water emulsion. Moreover, at all the concentrations examined, the purified component 3 showed a higher emulsifying activity than the total unpurified fraction.
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Dynamic Surface Properties of the Proteose-Peptone Fraction of Bovine Milk
Journal of Dairy Science, 1998Co-Authors: Nadia Innocente, Cesare Corradini, Christophe Blecker, Michel PaquotAbstract:Proteose-peptone is a heat-stable and acid-soluble protein fraction of milk that has important functional properties. Component 3, which is the most hydrophobic fraction, appears to be largely responsible for the physicochemical properties of Proteose-Peptones and for their important biological role in milk. In this study, total Proteose-peptone was prepared from bulk skim milk by precipitation with ammonium sulfate, and the hydrophobic fraction was purified by FPLC® (Pharmacia Fine Chemicals, Uppsala, Sweden). The drop volume method was used to investigate the dynamic surface activity of total Proteose-peptone and component 3 of Proteose-peptone at the air-water interface and at the oil-water interface. In general, Proteose-Peptones are good surfactants at both interfaces. Of all Proteose-Peptones, component 3 causes a more rapid reduction of interfacial tension in both interfaces. A system for measuring film balance was used to obtain more information about the surface and mechanical properties of Proteose-peptone monolayers. We deduced from the compression isotherms that component 3 of Proteose-peptone and total Proteose-peptone films spread at the air-water interface present different mechanical properties.
