ABSTRACT According to food safety agencies, Western consumers need to adjust their lipid intake a... more ABSTRACT According to food safety agencies, Western consumers need to adjust their lipid intake and opt for polyunsaturated fats—more specifically, those containing n-3 fatty acids. However, these fats tend to oxidize during technological operations, storage, and digestion. The resulting products of lipid oxidation lead to the development of off-flavors that decrease the food acceptability of the products. They also could contribute to the development of pathologies, such as chronic inflammation, metabolic syndrome, and colon cancer (Awada et al., 2012; Guéraud et al., 2010; Kanazawa et al., 2002; Pillon et al., 2009; Zarrouki et al., 2007). In many enriched-food formulations, polyunsaturated lipids are organized in the form of oil droplets that are dispersed in a more or less hydrated matrix, so-called oil-in-water (O/W) emulsions. Hydrated matrices, such as dairy products, meat products, dressings, and soups, are also viewed as O/W emulsions. O/W emulsions can be delivery intermediates used during the formulation process to incorporate the healthy oils in the foods more easily than the original oils and fats. Additionally, they are the basis for many cosmetic, pharmaceutical, and medical applications, as for instance parenteral emulsions. Consequently, model oil-in- water emulsions have been widely used in recent years to better understand the mechanisms that control their physical and chemical stabilities. In this chapter, we will first introduce recent findings that address the role of the interfacial layer and emulsifiers in oxidation. Then, we present recent results of our laboratory in this area. We have focused on emulsions stabilized by monolayers of food-grade emulsifiers, and we propose new concepts for the role of proteins and lateral interface homogeneity in the development of oxidation.
Journal of the American Oil Chemists' Society, 1998
Volatile compounds from oxidized pork muscle phospholipids (PL) were analyzed by a purge-and-trap... more Volatile compounds from oxidized pork muscle phospholipids (PL) were analyzed by a purge-and-trap method. Total volatile compounds were highly correlated with thiobarbituric acid-reactive substances, mainly as a consequence of alkanals. Major compounds of the 32 identified substances were alkanals (6023 ng nonane equivalents/mg PL), followed by 2-alkenals (514 ng nonane eq/mg PL) and 2,4-alkadienals (368 ng nonane eq/mg PL). Hexanal
... Some authors find no effect of the droplet size distribution on the partition coefficients of... more ... Some authors find no effect of the droplet size distribution on the partition coefficients of aroma compounds ( [Druaux et al., 1996] , [Le Thanh et al., 1992] , [Miettinen et al., 2002] and [Rabe et al., 2003] ) while others do find a change in partition or release, depending on droplet ...
Proteins are widely used as emulsifiers in food emulsions. Model emulsions, designed to study emu... more Proteins are widely used as emulsifiers in food emulsions. Model emulsions, designed to study emulsifying properties of proteins and their conformation at the interfaces often contain a hydrocarbon as apolar phase instead of natural triglycerides as found in food products. Yet, some results indicate that the protein conformation at the interface depends on the nature of the apolar phase. Front-surface fluorescence spectroscopy was used to evidence differences in the structure of bovine serum albumin (BSA) adsorbed at the interface of emulsions prepared with different apolar phases: an hydrocarbon (n-dodecane), a synthetic medium-chain triglyceride (miglyol) and a natural vegetable oil (sunflower oil). Emulsions had similar size distributions of oil droplets. Front-surface fluorescence emission spectra of tryptophanyl residues of the protein (Trp) in emulsions, creams and serums varied as a function of the nature of hydrophobic phase. In emulsions and creams, wavelength of the maximum fluorescence intensities was blue-shifted as compared to the BSA solution. The shift was larger in creams than in emulsions and in samples containing dodecane than with the other apolar phases. Fourth derivative spectra of emulsions and creams exhibited two peaks assigned, respectively, to Trp located in hydrophilic and hydrophobic environments. The peaks were slightly red-shifted in the presence of sunflower oil as compared to miglyol and dodecane and the relative intensity of the "hydrophobic peak" was higher in dodecane. The effects were greater in creams than in emulsions. Fluorescence intensity of Trp was the highest in the serums of emulsions prepared with dodecane as compared to serums issued from sunflower oil and miglyol emulsions. Thus, proportion of adsorbed protein was lower in dodecane emulsions than with the other apolar phases. These results evidence that the mean environment of Trp was more hydrophobic in emulsions and creams than in solutions due to a displacement of some of the Trp of the protein to a more hydrophobic environment. Dodecane had the greatest impact on Trp environment (more hydrophobic) followed by miglyol and then by sunflower oil. This is likely due to differences in the conformation of the protein at the hydrocarbon-water interface as compared to the triacylglycerol-water ones. In addition, sunflower oil provoked a large decrease of Trp fluorescence intensity in emulsions and creams as compared to miglyol or dodecane. This could be due to contaminant quenchers in the oil or to interactions of the unsaturated fatty chains with the protein inducing quenching of the Trp. These observations should be related to the physical properties of the apolar phase and its molecular organization and interactions with the protein at the interface.
ABSTRACT This chapter reviews the use of emulsifiers in delivery systems and foods enriched in om... more ABSTRACT This chapter reviews the use of emulsifiers in delivery systems and foods enriched in omega-3 fatty acids. It begins by explaining the reasons why emulsifiers are required for formulation and stabilization of various multiphase systems, the focus being on oil-in-water emulsions, before going on to give an overview of the main classes of food-grade emulsifiers and their ability to stabilize emulsions and food formulations related to some of their molecular characteristics. The possible involvement of emulsifiers such as proteins and lecithins in delaying lipid oxidation is then presented, and the effects of emulsification and emulsifiers on flavour are also summarized. In conclusion, the potential for optimizing the bioavailability and the beneficial effects of polyunsaturated fatty acids through the control of lipid organization and the need for research in this area are underlined.
Proteins often stabilize food emulsions and are also able to promote or delay lipid oxidation in ... more Proteins often stabilize food emulsions and are also able to promote or delay lipid oxidation in complex systems. The purpose of this work was to investigate the relationship between metal ion availability and oxidative stability of oil-in-water emulsions stabilized by bovine serum albumin (BSA) or sodium caseinate (NaCas). Emulsions with similar and stable droplet size distributions were prepared with stripped sunflower oil (30 vol %) and protein solutions (20 g L(-)(1); pH = 6.5). In the absence of the water-soluble metal chelator EDTA, oxygen uptake, conjugated dienes, and volatile compounds developed faster in NaCas-stabilized emulsions than in those prepared with BSA. This effect is attributed to the chelating properties of NaCas and to electrostatic interactions that attract some metal ions at the interface where they could initiate lipid oxidation. When EDTA (100 muM) was present, oxidation was delayed to a greater extent in emulsions made with NaCas than in BSA stabilized emulsions. These conditions probably enabled NaCas to exert free-radical-scavenging activity.
Journal of the American Oil Chemists' Society, 2002
... Llamas for droplet size determinations, Isabelle Bronnec for her help in static headspace ana... more ... Llamas for droplet size determinations, Isabelle Bronnec for her help in static headspace analysis, and Nadine Mouhous-Riou and Vincent Ram-pon for their ... 7. Jacobsen, C., K. Hartvigsen, P. Lund, AS Meyer, J. Adler-Nissen, J. Holstborg, and G. Hølmer, Oxidation in Fish-Oil ...
... Lethuaut, Chantal Brossard Corresponding Author Contact Information , E-mail The Correspondin... more ... Lethuaut, Chantal Brossard Corresponding Author Contact Information , E-mail The Corresponding Author , Anne Meynier, Florence Rousseau, Geneviève ... Sweetness intensity of sucrose solutions decreased when lemon or licorice odour was simultaneously perceived by ortho ...
During digestion, lipids undergo modifications of their colloidal and molecular structures, which... more During digestion, lipids undergo modifications of their colloidal and molecular structures, which depend on the digestive conditions and the composition of the digestive juices. The aim of this work was to evaluate whether gastric pH and pepsin modulate the colloidal evolution and the bioacessibility of fatty acids of an oil-in-water emulsion stabilized by a protein during in vitro digestion. The fate of BSA-stabilized rapeseed oil-in-water emulsion during gastric phase at pH 2.5 or 4.0 with or without pepsin and its consequences on intestinal lipolysis was measured in the simulated gastric and duodenal conditions. The pH had limited impact but pepsin favoured flocculation and coalescence of the droplets, modulating the early stage of lipolysis but not its final extent.
ABSTRACT According to food safety agencies, Western consumers need to adjust their lipid intake a... more ABSTRACT According to food safety agencies, Western consumers need to adjust their lipid intake and opt for polyunsaturated fats—more specifically, those containing n-3 fatty acids. However, these fats tend to oxidize during technological operations, storage, and digestion. The resulting products of lipid oxidation lead to the development of off-flavors that decrease the food acceptability of the products. They also could contribute to the development of pathologies, such as chronic inflammation, metabolic syndrome, and colon cancer (Awada et al., 2012; Guéraud et al., 2010; Kanazawa et al., 2002; Pillon et al., 2009; Zarrouki et al., 2007). In many enriched-food formulations, polyunsaturated lipids are organized in the form of oil droplets that are dispersed in a more or less hydrated matrix, so-called oil-in-water (O/W) emulsions. Hydrated matrices, such as dairy products, meat products, dressings, and soups, are also viewed as O/W emulsions. O/W emulsions can be delivery intermediates used during the formulation process to incorporate the healthy oils in the foods more easily than the original oils and fats. Additionally, they are the basis for many cosmetic, pharmaceutical, and medical applications, as for instance parenteral emulsions. Consequently, model oil-in- water emulsions have been widely used in recent years to better understand the mechanisms that control their physical and chemical stabilities. In this chapter, we will first introduce recent findings that address the role of the interfacial layer and emulsifiers in oxidation. Then, we present recent results of our laboratory in this area. We have focused on emulsions stabilized by monolayers of food-grade emulsifiers, and we propose new concepts for the role of proteins and lateral interface homogeneity in the development of oxidation.
Journal of the American Oil Chemists' Society, 1998
Volatile compounds from oxidized pork muscle phospholipids (PL) were analyzed by a purge-and-trap... more Volatile compounds from oxidized pork muscle phospholipids (PL) were analyzed by a purge-and-trap method. Total volatile compounds were highly correlated with thiobarbituric acid-reactive substances, mainly as a consequence of alkanals. Major compounds of the 32 identified substances were alkanals (6023 ng nonane equivalents/mg PL), followed by 2-alkenals (514 ng nonane eq/mg PL) and 2,4-alkadienals (368 ng nonane eq/mg PL). Hexanal
... Some authors find no effect of the droplet size distribution on the partition coefficients of... more ... Some authors find no effect of the droplet size distribution on the partition coefficients of aroma compounds ( [Druaux et al., 1996] , [Le Thanh et al., 1992] , [Miettinen et al., 2002] and [Rabe et al., 2003] ) while others do find a change in partition or release, depending on droplet ...
Proteins are widely used as emulsifiers in food emulsions. Model emulsions, designed to study emu... more Proteins are widely used as emulsifiers in food emulsions. Model emulsions, designed to study emulsifying properties of proteins and their conformation at the interfaces often contain a hydrocarbon as apolar phase instead of natural triglycerides as found in food products. Yet, some results indicate that the protein conformation at the interface depends on the nature of the apolar phase. Front-surface fluorescence spectroscopy was used to evidence differences in the structure of bovine serum albumin (BSA) adsorbed at the interface of emulsions prepared with different apolar phases: an hydrocarbon (n-dodecane), a synthetic medium-chain triglyceride (miglyol) and a natural vegetable oil (sunflower oil). Emulsions had similar size distributions of oil droplets. Front-surface fluorescence emission spectra of tryptophanyl residues of the protein (Trp) in emulsions, creams and serums varied as a function of the nature of hydrophobic phase. In emulsions and creams, wavelength of the maximum fluorescence intensities was blue-shifted as compared to the BSA solution. The shift was larger in creams than in emulsions and in samples containing dodecane than with the other apolar phases. Fourth derivative spectra of emulsions and creams exhibited two peaks assigned, respectively, to Trp located in hydrophilic and hydrophobic environments. The peaks were slightly red-shifted in the presence of sunflower oil as compared to miglyol and dodecane and the relative intensity of the "hydrophobic peak" was higher in dodecane. The effects were greater in creams than in emulsions. Fluorescence intensity of Trp was the highest in the serums of emulsions prepared with dodecane as compared to serums issued from sunflower oil and miglyol emulsions. Thus, proportion of adsorbed protein was lower in dodecane emulsions than with the other apolar phases. These results evidence that the mean environment of Trp was more hydrophobic in emulsions and creams than in solutions due to a displacement of some of the Trp of the protein to a more hydrophobic environment. Dodecane had the greatest impact on Trp environment (more hydrophobic) followed by miglyol and then by sunflower oil. This is likely due to differences in the conformation of the protein at the hydrocarbon-water interface as compared to the triacylglycerol-water ones. In addition, sunflower oil provoked a large decrease of Trp fluorescence intensity in emulsions and creams as compared to miglyol or dodecane. This could be due to contaminant quenchers in the oil or to interactions of the unsaturated fatty chains with the protein inducing quenching of the Trp. These observations should be related to the physical properties of the apolar phase and its molecular organization and interactions with the protein at the interface.
ABSTRACT This chapter reviews the use of emulsifiers in delivery systems and foods enriched in om... more ABSTRACT This chapter reviews the use of emulsifiers in delivery systems and foods enriched in omega-3 fatty acids. It begins by explaining the reasons why emulsifiers are required for formulation and stabilization of various multiphase systems, the focus being on oil-in-water emulsions, before going on to give an overview of the main classes of food-grade emulsifiers and their ability to stabilize emulsions and food formulations related to some of their molecular characteristics. The possible involvement of emulsifiers such as proteins and lecithins in delaying lipid oxidation is then presented, and the effects of emulsification and emulsifiers on flavour are also summarized. In conclusion, the potential for optimizing the bioavailability and the beneficial effects of polyunsaturated fatty acids through the control of lipid organization and the need for research in this area are underlined.
Proteins often stabilize food emulsions and are also able to promote or delay lipid oxidation in ... more Proteins often stabilize food emulsions and are also able to promote or delay lipid oxidation in complex systems. The purpose of this work was to investigate the relationship between metal ion availability and oxidative stability of oil-in-water emulsions stabilized by bovine serum albumin (BSA) or sodium caseinate (NaCas). Emulsions with similar and stable droplet size distributions were prepared with stripped sunflower oil (30 vol %) and protein solutions (20 g L(-)(1); pH = 6.5). In the absence of the water-soluble metal chelator EDTA, oxygen uptake, conjugated dienes, and volatile compounds developed faster in NaCas-stabilized emulsions than in those prepared with BSA. This effect is attributed to the chelating properties of NaCas and to electrostatic interactions that attract some metal ions at the interface where they could initiate lipid oxidation. When EDTA (100 muM) was present, oxidation was delayed to a greater extent in emulsions made with NaCas than in BSA stabilized emulsions. These conditions probably enabled NaCas to exert free-radical-scavenging activity.
Journal of the American Oil Chemists' Society, 2002
... Llamas for droplet size determinations, Isabelle Bronnec for her help in static headspace ana... more ... Llamas for droplet size determinations, Isabelle Bronnec for her help in static headspace analysis, and Nadine Mouhous-Riou and Vincent Ram-pon for their ... 7. Jacobsen, C., K. Hartvigsen, P. Lund, AS Meyer, J. Adler-Nissen, J. Holstborg, and G. Hølmer, Oxidation in Fish-Oil ...
... Lethuaut, Chantal Brossard Corresponding Author Contact Information , E-mail The Correspondin... more ... Lethuaut, Chantal Brossard Corresponding Author Contact Information , E-mail The Corresponding Author , Anne Meynier, Florence Rousseau, Geneviève ... Sweetness intensity of sucrose solutions decreased when lemon or licorice odour was simultaneously perceived by ortho ...
During digestion, lipids undergo modifications of their colloidal and molecular structures, which... more During digestion, lipids undergo modifications of their colloidal and molecular structures, which depend on the digestive conditions and the composition of the digestive juices. The aim of this work was to evaluate whether gastric pH and pepsin modulate the colloidal evolution and the bioacessibility of fatty acids of an oil-in-water emulsion stabilized by a protein during in vitro digestion. The fate of BSA-stabilized rapeseed oil-in-water emulsion during gastric phase at pH 2.5 or 4.0 with or without pepsin and its consequences on intestinal lipolysis was measured in the simulated gastric and duodenal conditions. The pH had limited impact but pepsin favoured flocculation and coalescence of the droplets, modulating the early stage of lipolysis but not its final extent.
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