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Harjinder Singh - One of the best experts on this subject based on the ideXlab platform.
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Nature's complex emulsion: The fat Globules of milk
Food Hydrocolloids, 2017Co-Authors: Harjinder Singh, Sophie GallierAbstract:Abstract The milk fat Globule in milk represents a unique emulsion system designed by Nature to deliver energy, essential fatty acids and lipid-soluble nutrients to the neonate. The fat Globules range from 0.1 to 15 μm in diameter and are stabilised by milk fat Globule membrane (MFGM) which is composed of phospholipids, various glycoproteins, enzymes and cholesterol. Extensive knowledge on the intracellular origin, composition and structure of fat Globules and MFGM has been accumulated over the last 30 years. Recently, it has been speculated that the MFGM has profound effects on the accessibility of the triglycerides for lipase-catalysed digestion. This has initiated a large number of studies on the digestion of milk fat Globules in various dairy systems involving both in vitro and in vivo human digestion models. In addition, the identification of health-beneficial components of MFGM has led to increasing interest in developing MFGM as a food ingredient with unique functional properties and health benefits. This review focuses on recent knowledge on composition and structure of fat Globules, the MFGM, and the behaviour of fat Globules during gastro-intestinal digestion. MFGM ingredients and their applications are briefly discussed.
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proteolysis of milk fat Globule membrane proteins during in vitro gastric digestion of milk
Journal of Dairy Science, 2011Co-Authors: Aiqian Ye, Harjinder SinghAbstract:The influence of gastric proteolysis on the physicochemical characteristics of milk fat Globules and the proteins of the milk fat Globule membrane (MFGM) in raw milk and cream was examined in vitro in simulated gastric fluid (SGF) containing various pepsin concentrations at pH 1.6 for up to 2 h. Apparent flocculation of the milk fat Globules occurred in raw milk samples incubated in SGF containing pepsin, but no coalescence was observed in either raw milk samples or cream samples. The changes in the particle size of the fat Globules as a result of the flocculation were dependent on the pepsin concentration. Correspondingly, the physical characteristics of the fat Globules and the composition of the MFGM proteins in raw milk changed during incubation in SGF containing pepsin. The major MFGM proteins were hydrolyzed at different rates by the pepsin in the SGF; butyrophilin was more resistant than xanthine oxidase, PAS 6, or PAS 7. Peptides with various molecular weights, which altered with the time of incubation and the pepsin concentration, were present at the surfaces of the fat Globules.
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Effect of the fat Globule membrane on in vitro digestion of milk fat Globules with pancreatic lipase.
International Dairy Journal, 2010Co-Authors: Aiqian Ye, Harjinder SinghAbstract:The rate and extent of in vitro lipid digestion in raw and recombined milk were investigated by determining the release of fatty acids in simulated intestinal fluid containing pancreatic lipase. Changes in the Globule size, surface charge and microstructure of fat Globules during digestion were examined. In the absence of bile extract, the rate of lipid digestion was slower in raw milk than in recombined milk, suggesting that the composition of the milk fat Globule membrane influences the rate of lipid hydrolysis in milk. Flocculation of fat Globules occurred in the early stages of digestion; the Globules then coalesced to form large particles, from within which triacylglycerols were removed. However, in the presence of bile extract, the changes in the size and microstructure of the fat Globules during digestion were different. Bile extract may therefore affect physicochemical interactions of fat Globules and hence alter the lipolysis during the digestion.
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Controlling milk protein interactions to enhance the reconstitution properties of whole milk powders — A minireview
Dairy Science & Technology, 2010Co-Authors: Harjinder Singh, Aiqian YeAbstract:Les poudres de lait séché par atomisation sont largement utilisées dans les produits laitiers recombinés et les aliments transformés. Les interactions des composants spécifiques du lait, comme les micelles de caséines, les protéines sériques et les Globules gras, conditionnent le comportement du lait au cours du traitement et les propriétés fonctionnelles de la poudre dans différentes applications. La fabrication de poudres de lait implique traitements thermiques, évaporation, homogénéisation et séchage par atomisation. L’effet principal du traitement thermique est la dénaturation des protéines sériques et leur association avec les micelles de caséine. Au cours de l’évaporation, la taille des micelles de caséine augmente, principalement à cause de l’agrégation de certaines micelles et de l’association accrue des protéines sériques avec les micelles. Au cours de la fabrication de poudre de lait entier, il y a également des changements considérables dans la taille des Globules gras du lait et dans la composition protéique de leur membrane. Cette composition modifiée et la réactivité conséquente de la membrane des Globules gras jouent un rôle important dans la détermination des propriétés fonctionnelles des poudres de lait entier, en particulier leurs propriétés de reconstitution. Spray-dried milk powders are widely used in recombined milk products and processed foods. The interactions of the specific components in milk, i.e. casein micelles, whey proteins and fat Globules, dictate how milk will behave during processing and the functional properties of the powder in different applications. The manufacture of milk powders involves heat treatments, evaporation, homogenisation and spray drying. The major effect of heat treatment is the denaturation of whey proteins and their association with casein micelles. During evaporation, the casein micelle size increases due mainly to the aggregation of some of the micelles and increased association of the whey proteins with the micelles. During whole milk powder manufacture, there are also considerable changes in the size of fat Globules and the protein composition of the milk fat Globule membrane (MFGM). This modified composition and the consequent reactivity of the MFGM play a major role in determining the functionality of whole milk powders, in particular its reconstitution properties.
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Effect of the fat Globule membrane on in vitro digestion of milk fat Globules with pancreatic lipase
International Dairy Journal, 2010Co-Authors: Aiqian Ye, Jian Cui, Harjinder SinghAbstract:The rate and extent of in vitro lipid digestion in raw and recombined milk were investigated by determining the release of fatty acids in simulated intestinal fluid containing pancreatic lipase. Changes in the Globule size, surface charge and microstructure of fat Globules during digestion were examined. In the absence of bile extract, the rate of lipid digestion was slower in raw milk than in recombined milk, suggesting that the composition of the milk fat Globule membrane influences the rate of lipid hydrolysis in milk. Flocculation of fat Globules occurred in the early stages of digestion; the Globules then coalesced to form large particles, from within which triacylglycerols were removed. However, in the presence of bile extract, the changes in the size and microstructure of the fat Globules during digestion were different. Bile extract may therefore affect physicochemical interactions of fat Globules and hence alter the lipolysis during the digestion. © 2010 Elsevier Ltd.
Christelle Lopez - One of the best experts on this subject based on the ideXlab platform.
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Organization of lipids in milks, infant milk formulas and various dairy products: role of technological processes and potential impacts
Dairy Science and Technology, 2015Co-Authors: Christelle Lopez, Chantal Cauty, Fanny Guyomarc’hAbstract:The microstructure of milk fat in processed dairy products is poorly known despite its importance in their functional, sensorial and nutritional properties. However, for the last 10 years, several research groups including our laboratory have significantly contributed to increasing knowledge on the organization of lipids in situ in dairy products. This paper provides an overview of recent advances on the organization of lipids in the milk fat Globule membrane using microscopy techniques (mainly confocal microscopy and atomic force microscopy). Also, this overview brings structural information about the organization of lipids in situ in commercialized milks, infant milk formulas and various dairy products (cream, butter, buttermilk, butter serum and cheeses). The main mechanical treatment used in the dairy industry, homogenization, decreases the size of milk fat Globules, changes the architecture (composition and organization) of the fat/water interface and affects the interactions between lipid droplets and the protein network (concept of inert vs active fillers). The potential impacts of the organization of lipids and of the alteration of the milk fat Globule membrane are discussed, and technological strategies are proposed, in priority to design biomimetic lipid droplets in infant milk formulas.
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fat Globules selected from whole milk according to their size different compositions and structure of the biomembrane revealing sphingomyelin rich domains
Food Chemistry, 2011Co-Authors: Christelle Lopez, Olivia Menard, Florence Rousseau, Nadine Leconte, Jacques Fauquant, Valerie Briardbion, Eric Beaucher, Benoit RobertAbstract:Abstract Milk fat Globules are unique delivery systems for biologically active molecules in the gastrointestinal tract. However, their properties have not yet been fully investigated. In this study, we performed a comparative analysis of the polar lipid and fatty acid compositions of milk fat Globules as a function of their size and investigated the structure of the milk fat Globule membrane (MFGM). An optimised process of microfiltration was used to select the small milk fat Globule (SMFG; 1.6 μm) fractions and the large milk fat Globule (LMFG; 6.6 μm) fractions from the same initial whole milks (4.2 μm). The SMFG-fractions contained significantly (i) higher amounts of polar lipids, 8.9 ± 0.9 vs 2.7 ± 0.3 mg/g fat for LMFG-fractions and 6.3 ± 0.5 mg/g fat for whole milks, (ii) lower relative proportions of phosphatidylcholine and sphingomyelin in the MFGM, (iii) higher amounts of C12:0, C14:0, C16:0, C18:1 trans , C18:2 c9 tr11, and lower amounts of C18:0 and C18:1 c9 than did LMFG-fractions and whole milks. Whatever the size of native milk fat Globules, the biophysical characterisation performed in-situ , using confocal laser scanning microscopy, showed heterogeneities in the MFGM. The lateral segregation of sphingomyelin in rigid liquid-ordered domains, surrounded by the fluid matrix of glycerophospholipids in the liquid-disordered phase, was revealed. The heterogeneous distribution of glycolipids and glycoproteins was also observed in the MFGM. A new model for the structure of the MFGM is proposed and discussed. The physical, chemical and biological consequences, (i) of the differences in milk fat Globule compositions according to their size and (ii) of the specific structure of the MFGM due to sphingomyelin remain to be elucidated.
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buffalo vs cow milk fat Globules size distribution zeta potential compositions in total fatty acids and in polar lipids from the milk fat Globule membrane
Food Chemistry, 2010Co-Authors: Olivia Menard, Sarfraz Ahmad, Florence Rousseau, Frederic Gaucheron, Valerie Briardbion, Christelle LopezAbstract:Although buffalo milk is the second most produced milk in the world, and of primary nutritional importance in various parts of the world, few studies have focused on the physicochemical properties of buffalo milk fat Globules. This study is a comparative analysis of buffalo and cow milk fat Globules. The larger size of buffalo fat Globules, 5 vs. 3.5 lm, was related to the higher amount of fat in the buffalo milks: 73.4 ± 9.9 vs. 41.3 ± 3.7 g/kg for cow milk. Buffalo milks contained significantly lower amount of polar lipids expressed per gram of lipids (0.26% vs. 0.36%), but significantly higher amount of polar lipids per litre of milk (+26%). Buffalo and cow milk fat Globule membranes contain the same classes of polar lipids; phosphatidylethanolamine, sphingomyelin (SM) and phosphatidylcholine (PC) being the main constituents. A significant higher percentage of PC and lower percentage of SM were found for buffalo milks. The fatty acid analysis revealed that saturated fatty acids, mainly palmitic acid, trans fatty acids, linolenic acid (x3) and conjugated linolenic acid were higher in buffalo milk than in cow milk. Such results will contribute to the improvement of the quality of buffalo milk-based dairy products.
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lipid rafts in the bovine milk fat Globule membrane revealed by the lateral segregation of phospholipids and heterogeneous distribution of glycoproteins
Food Chemistry, 2010Co-Authors: Christelle Lopez, Marienoelle Madec, Rafael JimenezfloresAbstract:This study reveals the lateral organisation of the milk fat Globule membrane (MFGM). Using confocal laser scanning microscopy (CLSM) and a lipid soluble molecule, an exogenous phospholipid and two lectins as fluorescent probes we located triacylglycerols in the core of fat Globules and investigated the organisation of the polar lipids and glycoproteins of the MFGM, in situ in milk. Lipid rafts corresponding to the lateral segregation of sphingolipids in liquid-ordered phases surrounded by liquid-disordered domains composed by the glycerophospholipids were observed in the MFGM. These lipid rafts which correspond to rigid sphingolipid-rich domains have a circular shape at room temperature. CLSM experiments revealed that glycoproteins and glycolipids are heterogeneously distributed around fat Globules and that they are not located in the lipid rafts. The characterisations performed by in depth thin sectioning of fat Globules and in dynamic as a function of time revealed chemical and structural heterogeneities in the MFGM. Schematic 3D and 2D representations of the MFGM are proposed and discussed. The physiological and nutritional consequences of the lateral organisation of polar lipids and glycoproteins in the MFGM are discussed but remain to be elucidated.
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Buffalo vs. cow milk fat Globules: Size distribution, zeta-potential, compositions in total fatty acids and in polar lipids from the milk fat Globule membrane
Food Chemistry, 2010Co-Authors: Olivia Menard, Valérie Briard-bion, Sarfraz Ahmad, Florence Rousseau, Frederic Gaucheron, Christelle LopezAbstract:Although buffalo milk is the second most produced milk in the world, and of primary nutritional importance in various parts of the world, few studies have focused on the physicochemical properties of buffalo milk fat Globules. This study is a comparative analysis of buffalo and cow milk fat Globules. The larger size of buffalo fat Globules, 5 vs. 3.5 μm, was related to the higher amount of fat in the buffalo milks: 73.4 ± 9.9 vs. 41.3 ± 3.7 g/kg for cow milk. Buffalo milks contained significantly lower amount of polar lipids expressed per gram of lipids (0.26% vs. 0.36%), but significantly higher amount of polar lipids per litre of milk (+26%). Buffalo and cow milk fat Globule membranes contain the same classes of polar lipids; phosphatidylethanolamine, sphingomyelin (SM) and phosphatidylcholine (PC) being the main constituents. A significant higher percentage of PC and lower percentage of SM were found for buffalo milks. The fatty acid analysis revealed that saturated fatty acids, mainly palmitic acid, trans fatty acids, linolenic acid (ω3) and conjugated linolenic acid were higher in buffalo milk than in cow milk. Such results will contribute to the improvement of the quality of buffalo milk-based dairy products. © 2009 Elsevier Ltd. All rights reserved.
Olivia Menard - One of the best experts on this subject based on the ideXlab platform.
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fat Globules selected from whole milk according to their size different compositions and structure of the biomembrane revealing sphingomyelin rich domains
Food Chemistry, 2011Co-Authors: Christelle Lopez, Olivia Menard, Florence Rousseau, Nadine Leconte, Jacques Fauquant, Valerie Briardbion, Eric Beaucher, Benoit RobertAbstract:Abstract Milk fat Globules are unique delivery systems for biologically active molecules in the gastrointestinal tract. However, their properties have not yet been fully investigated. In this study, we performed a comparative analysis of the polar lipid and fatty acid compositions of milk fat Globules as a function of their size and investigated the structure of the milk fat Globule membrane (MFGM). An optimised process of microfiltration was used to select the small milk fat Globule (SMFG; 1.6 μm) fractions and the large milk fat Globule (LMFG; 6.6 μm) fractions from the same initial whole milks (4.2 μm). The SMFG-fractions contained significantly (i) higher amounts of polar lipids, 8.9 ± 0.9 vs 2.7 ± 0.3 mg/g fat for LMFG-fractions and 6.3 ± 0.5 mg/g fat for whole milks, (ii) lower relative proportions of phosphatidylcholine and sphingomyelin in the MFGM, (iii) higher amounts of C12:0, C14:0, C16:0, C18:1 trans , C18:2 c9 tr11, and lower amounts of C18:0 and C18:1 c9 than did LMFG-fractions and whole milks. Whatever the size of native milk fat Globules, the biophysical characterisation performed in-situ , using confocal laser scanning microscopy, showed heterogeneities in the MFGM. The lateral segregation of sphingomyelin in rigid liquid-ordered domains, surrounded by the fluid matrix of glycerophospholipids in the liquid-disordered phase, was revealed. The heterogeneous distribution of glycolipids and glycoproteins was also observed in the MFGM. A new model for the structure of the MFGM is proposed and discussed. The physical, chemical and biological consequences, (i) of the differences in milk fat Globule compositions according to their size and (ii) of the specific structure of the MFGM due to sphingomyelin remain to be elucidated.
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buffalo vs cow milk fat Globules size distribution zeta potential compositions in total fatty acids and in polar lipids from the milk fat Globule membrane
Food Chemistry, 2010Co-Authors: Olivia Menard, Sarfraz Ahmad, Florence Rousseau, Frederic Gaucheron, Valerie Briardbion, Christelle LopezAbstract:Although buffalo milk is the second most produced milk in the world, and of primary nutritional importance in various parts of the world, few studies have focused on the physicochemical properties of buffalo milk fat Globules. This study is a comparative analysis of buffalo and cow milk fat Globules. The larger size of buffalo fat Globules, 5 vs. 3.5 lm, was related to the higher amount of fat in the buffalo milks: 73.4 ± 9.9 vs. 41.3 ± 3.7 g/kg for cow milk. Buffalo milks contained significantly lower amount of polar lipids expressed per gram of lipids (0.26% vs. 0.36%), but significantly higher amount of polar lipids per litre of milk (+26%). Buffalo and cow milk fat Globule membranes contain the same classes of polar lipids; phosphatidylethanolamine, sphingomyelin (SM) and phosphatidylcholine (PC) being the main constituents. A significant higher percentage of PC and lower percentage of SM were found for buffalo milks. The fatty acid analysis revealed that saturated fatty acids, mainly palmitic acid, trans fatty acids, linolenic acid (x3) and conjugated linolenic acid were higher in buffalo milk than in cow milk. Such results will contribute to the improvement of the quality of buffalo milk-based dairy products.
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Buffalo vs. cow milk fat Globules: Size distribution, zeta-potential, compositions in total fatty acids and in polar lipids from the milk fat Globule membrane
Food Chemistry, 2010Co-Authors: Olivia Menard, Valérie Briard-bion, Sarfraz Ahmad, Florence Rousseau, Frederic Gaucheron, Christelle LopezAbstract:Although buffalo milk is the second most produced milk in the world, and of primary nutritional importance in various parts of the world, few studies have focused on the physicochemical properties of buffalo milk fat Globules. This study is a comparative analysis of buffalo and cow milk fat Globules. The larger size of buffalo fat Globules, 5 vs. 3.5 μm, was related to the higher amount of fat in the buffalo milks: 73.4 ± 9.9 vs. 41.3 ± 3.7 g/kg for cow milk. Buffalo milks contained significantly lower amount of polar lipids expressed per gram of lipids (0.26% vs. 0.36%), but significantly higher amount of polar lipids per litre of milk (+26%). Buffalo and cow milk fat Globule membranes contain the same classes of polar lipids; phosphatidylethanolamine, sphingomyelin (SM) and phosphatidylcholine (PC) being the main constituents. A significant higher percentage of PC and lower percentage of SM were found for buffalo milks. The fatty acid analysis revealed that saturated fatty acids, mainly palmitic acid, trans fatty acids, linolenic acid (ω3) and conjugated linolenic acid were higher in buffalo milk than in cow milk. Such results will contribute to the improvement of the quality of buffalo milk-based dairy products. © 2009 Elsevier Ltd. All rights reserved.
Aiqian Ye - One of the best experts on this subject based on the ideXlab platform.
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proteolysis of milk fat Globule membrane proteins during in vitro gastric digestion of milk
Journal of Dairy Science, 2011Co-Authors: Aiqian Ye, Harjinder SinghAbstract:The influence of gastric proteolysis on the physicochemical characteristics of milk fat Globules and the proteins of the milk fat Globule membrane (MFGM) in raw milk and cream was examined in vitro in simulated gastric fluid (SGF) containing various pepsin concentrations at pH 1.6 for up to 2 h. Apparent flocculation of the milk fat Globules occurred in raw milk samples incubated in SGF containing pepsin, but no coalescence was observed in either raw milk samples or cream samples. The changes in the particle size of the fat Globules as a result of the flocculation were dependent on the pepsin concentration. Correspondingly, the physical characteristics of the fat Globules and the composition of the MFGM proteins in raw milk changed during incubation in SGF containing pepsin. The major MFGM proteins were hydrolyzed at different rates by the pepsin in the SGF; butyrophilin was more resistant than xanthine oxidase, PAS 6, or PAS 7. Peptides with various molecular weights, which altered with the time of incubation and the pepsin concentration, were present at the surfaces of the fat Globules.
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Effect of the fat Globule membrane on in vitro digestion of milk fat Globules with pancreatic lipase.
International Dairy Journal, 2010Co-Authors: Aiqian Ye, Harjinder SinghAbstract:The rate and extent of in vitro lipid digestion in raw and recombined milk were investigated by determining the release of fatty acids in simulated intestinal fluid containing pancreatic lipase. Changes in the Globule size, surface charge and microstructure of fat Globules during digestion were examined. In the absence of bile extract, the rate of lipid digestion was slower in raw milk than in recombined milk, suggesting that the composition of the milk fat Globule membrane influences the rate of lipid hydrolysis in milk. Flocculation of fat Globules occurred in the early stages of digestion; the Globules then coalesced to form large particles, from within which triacylglycerols were removed. However, in the presence of bile extract, the changes in the size and microstructure of the fat Globules during digestion were different. Bile extract may therefore affect physicochemical interactions of fat Globules and hence alter the lipolysis during the digestion.
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Controlling milk protein interactions to enhance the reconstitution properties of whole milk powders — A minireview
Dairy Science & Technology, 2010Co-Authors: Harjinder Singh, Aiqian YeAbstract:Les poudres de lait séché par atomisation sont largement utilisées dans les produits laitiers recombinés et les aliments transformés. Les interactions des composants spécifiques du lait, comme les micelles de caséines, les protéines sériques et les Globules gras, conditionnent le comportement du lait au cours du traitement et les propriétés fonctionnelles de la poudre dans différentes applications. La fabrication de poudres de lait implique traitements thermiques, évaporation, homogénéisation et séchage par atomisation. L’effet principal du traitement thermique est la dénaturation des protéines sériques et leur association avec les micelles de caséine. Au cours de l’évaporation, la taille des micelles de caséine augmente, principalement à cause de l’agrégation de certaines micelles et de l’association accrue des protéines sériques avec les micelles. Au cours de la fabrication de poudre de lait entier, il y a également des changements considérables dans la taille des Globules gras du lait et dans la composition protéique de leur membrane. Cette composition modifiée et la réactivité conséquente de la membrane des Globules gras jouent un rôle important dans la détermination des propriétés fonctionnelles des poudres de lait entier, en particulier leurs propriétés de reconstitution. Spray-dried milk powders are widely used in recombined milk products and processed foods. The interactions of the specific components in milk, i.e. casein micelles, whey proteins and fat Globules, dictate how milk will behave during processing and the functional properties of the powder in different applications. The manufacture of milk powders involves heat treatments, evaporation, homogenisation and spray drying. The major effect of heat treatment is the denaturation of whey proteins and their association with casein micelles. During evaporation, the casein micelle size increases due mainly to the aggregation of some of the micelles and increased association of the whey proteins with the micelles. During whole milk powder manufacture, there are also considerable changes in the size of fat Globules and the protein composition of the milk fat Globule membrane (MFGM). This modified composition and the consequent reactivity of the MFGM play a major role in determining the functionality of whole milk powders, in particular its reconstitution properties.
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Effect of the fat Globule membrane on in vitro digestion of milk fat Globules with pancreatic lipase
International Dairy Journal, 2010Co-Authors: Aiqian Ye, Jian Cui, Harjinder SinghAbstract:The rate and extent of in vitro lipid digestion in raw and recombined milk were investigated by determining the release of fatty acids in simulated intestinal fluid containing pancreatic lipase. Changes in the Globule size, surface charge and microstructure of fat Globules during digestion were examined. In the absence of bile extract, the rate of lipid digestion was slower in raw milk than in recombined milk, suggesting that the composition of the milk fat Globule membrane influences the rate of lipid hydrolysis in milk. Flocculation of fat Globules occurred in the early stages of digestion; the Globules then coalesced to form large particles, from within which triacylglycerols were removed. However, in the presence of bile extract, the changes in the size and microstructure of the fat Globules during digestion were different. Bile extract may therefore affect physicochemical interactions of fat Globules and hence alter the lipolysis during the digestion. © 2010 Elsevier Ltd.
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Behaviour of homogenized fat Globules during the spray drying of whole milk
International Dairy Journal, 2007Co-Authors: Aiqian Ye, Skelte G Anema, Harjinder SinghAbstract:The changes in milk fat Globule size and fat Globule surface proteins of both low-preheated and high-preheated concentrated milks, which were homogenized at low or high pressure prior to spray drying using a disc atomization drier, were examined. The average fat Globule size (d32) of the spray-dried milk powders was smaller than that of the corresponding concentrates, but a small proportion of very large Globules (4-80 ??m) was also formed during spray drying. As a consequence, total surface protein (mg protein g-1 fat) increased due to the adsorption of casein micelles at the fat Globule surface during spray drying. Confocal micrographs of the powders showed some apparent spreading of the fat on the surface of the powder particles, particularly when the concentrates were homogenized at low pressure. These results indicate disruption of the milk fat Globules during spray drying, which consequently causes changes in the fat Globule surface protein layer. ?? 2006 Elsevier Ltd. All rights reserved.
Florence Rousseau - One of the best experts on this subject based on the ideXlab platform.
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fat Globules selected from whole milk according to their size different compositions and structure of the biomembrane revealing sphingomyelin rich domains
Food Chemistry, 2011Co-Authors: Christelle Lopez, Olivia Menard, Florence Rousseau, Nadine Leconte, Jacques Fauquant, Valerie Briardbion, Eric Beaucher, Benoit RobertAbstract:Abstract Milk fat Globules are unique delivery systems for biologically active molecules in the gastrointestinal tract. However, their properties have not yet been fully investigated. In this study, we performed a comparative analysis of the polar lipid and fatty acid compositions of milk fat Globules as a function of their size and investigated the structure of the milk fat Globule membrane (MFGM). An optimised process of microfiltration was used to select the small milk fat Globule (SMFG; 1.6 μm) fractions and the large milk fat Globule (LMFG; 6.6 μm) fractions from the same initial whole milks (4.2 μm). The SMFG-fractions contained significantly (i) higher amounts of polar lipids, 8.9 ± 0.9 vs 2.7 ± 0.3 mg/g fat for LMFG-fractions and 6.3 ± 0.5 mg/g fat for whole milks, (ii) lower relative proportions of phosphatidylcholine and sphingomyelin in the MFGM, (iii) higher amounts of C12:0, C14:0, C16:0, C18:1 trans , C18:2 c9 tr11, and lower amounts of C18:0 and C18:1 c9 than did LMFG-fractions and whole milks. Whatever the size of native milk fat Globules, the biophysical characterisation performed in-situ , using confocal laser scanning microscopy, showed heterogeneities in the MFGM. The lateral segregation of sphingomyelin in rigid liquid-ordered domains, surrounded by the fluid matrix of glycerophospholipids in the liquid-disordered phase, was revealed. The heterogeneous distribution of glycolipids and glycoproteins was also observed in the MFGM. A new model for the structure of the MFGM is proposed and discussed. The physical, chemical and biological consequences, (i) of the differences in milk fat Globule compositions according to their size and (ii) of the specific structure of the MFGM due to sphingomyelin remain to be elucidated.
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buffalo vs cow milk fat Globules size distribution zeta potential compositions in total fatty acids and in polar lipids from the milk fat Globule membrane
Food Chemistry, 2010Co-Authors: Olivia Menard, Sarfraz Ahmad, Florence Rousseau, Frederic Gaucheron, Valerie Briardbion, Christelle LopezAbstract:Although buffalo milk is the second most produced milk in the world, and of primary nutritional importance in various parts of the world, few studies have focused on the physicochemical properties of buffalo milk fat Globules. This study is a comparative analysis of buffalo and cow milk fat Globules. The larger size of buffalo fat Globules, 5 vs. 3.5 lm, was related to the higher amount of fat in the buffalo milks: 73.4 ± 9.9 vs. 41.3 ± 3.7 g/kg for cow milk. Buffalo milks contained significantly lower amount of polar lipids expressed per gram of lipids (0.26% vs. 0.36%), but significantly higher amount of polar lipids per litre of milk (+26%). Buffalo and cow milk fat Globule membranes contain the same classes of polar lipids; phosphatidylethanolamine, sphingomyelin (SM) and phosphatidylcholine (PC) being the main constituents. A significant higher percentage of PC and lower percentage of SM were found for buffalo milks. The fatty acid analysis revealed that saturated fatty acids, mainly palmitic acid, trans fatty acids, linolenic acid (x3) and conjugated linolenic acid were higher in buffalo milk than in cow milk. Such results will contribute to the improvement of the quality of buffalo milk-based dairy products.
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Buffalo vs. cow milk fat Globules: Size distribution, zeta-potential, compositions in total fatty acids and in polar lipids from the milk fat Globule membrane
Food Chemistry, 2010Co-Authors: Olivia Menard, Valérie Briard-bion, Sarfraz Ahmad, Florence Rousseau, Frederic Gaucheron, Christelle LopezAbstract:Although buffalo milk is the second most produced milk in the world, and of primary nutritional importance in various parts of the world, few studies have focused on the physicochemical properties of buffalo milk fat Globules. This study is a comparative analysis of buffalo and cow milk fat Globules. The larger size of buffalo fat Globules, 5 vs. 3.5 μm, was related to the higher amount of fat in the buffalo milks: 73.4 ± 9.9 vs. 41.3 ± 3.7 g/kg for cow milk. Buffalo milks contained significantly lower amount of polar lipids expressed per gram of lipids (0.26% vs. 0.36%), but significantly higher amount of polar lipids per litre of milk (+26%). Buffalo and cow milk fat Globule membranes contain the same classes of polar lipids; phosphatidylethanolamine, sphingomyelin (SM) and phosphatidylcholine (PC) being the main constituents. A significant higher percentage of PC and lower percentage of SM were found for buffalo milks. The fatty acid analysis revealed that saturated fatty acids, mainly palmitic acid, trans fatty acids, linolenic acid (ω3) and conjugated linolenic acid were higher in buffalo milk than in cow milk. Such results will contribute to the improvement of the quality of buffalo milk-based dairy products. © 2009 Elsevier Ltd. All rights reserved.