Interactions structures & functionalities team objectives

Interactions structures & functionalities team objectives. STLOpenday

β-Lactoglobulin-linoleate complexes: In vitro digestion and the role of protein in fatty acids uptake

peer-reviewedThe dairy protein β-lactoglobulin (BLG) is known to bind fatty acids such as the salt of the essential longchain fatty acid linoleic acid (cis,cis-9,12-octadecadienoic acid, n-6, 18:2). The aim of the current study was to investigate how bovine BLG-linoleate complexes, of various stoichiometry, affect the enzymatic digestion of BLG and the intracellular transport of linoleate into enterocyte-like monolayers. Duodenal and gastric digestions of the complexes indicated that BLG was hydrolyzed more rapidly when complexed with linoleate. Digested as well as undigested BLG-linoleate complexes reduced intracellular linoleate transport as compared with free linoleate. To investigate whether enteroendocrine cells perceive linoleate differently when part of a complex, the ability of linoleate to increase production or secretion of the enteroendocrine satiety hormone, cholecystokinin, was measured. Cholecystokinin mRNA levels were different when linoleate was presented to the cells alone or as part of a protein complex. In conclusion, understanding interactions between linoleate and BLG could help to formulate foods with targeted fatty acid bioaccessibility and, therefore, aid in the development of food matrices with optimal bioactive efficacyS. Le Maux is currently supported by a Teagasc Walsh Fellowship and the Department of Agriculture, Fisheries and Food (FIRM project 08/RD/TMFRC/650). We also acknowledge funding from IRCSET-Ulysses Travel Grant

Kinetics of heat-induced denaturation of whey proteins and characterization of protein aggregates in model infant formulas

In 2018, about 60% of world’s newborns received cow milk-based infant formulas (IF) instead of human milk (UNICEF). The process of manufacturing IF involves heat treatments altering the physicochemical properties of milk components, especially whey proteins (WP), and so the rheological properties of IF. The objective of the study was to investigate the impacts of thermal treatments on the denaturation of WP of IF, particularly for those mimicking the protein profile of human milk, and to characterize the heat-induced protein structures.Three model IF were produced with a caseins:WP ratio of 40:60 at 1.3% and 5.5% of total proteins, i.e. the protein contents at which are applied heat treatments during the manufacture of liquid or powder IF, respectively. Skimmed milk was mixed with a WP isolate, a mix of WP isolate and purified lactoferrin or a mix of both purified lactoferrin and α-lactalbumin in proportion similar to that in human milk. The kinetic of heat-induced denaturation of each WP was investigated between 67.5°C and 80°C by RP-HPLC. The heat-induced protein structures were studied by dynamic light scattering, electrophoresis and asymmetric flow field flow fractionation coupled with MALLS.The results revealed that the extent of denaturation of WP depended on the protein content and the nature of the WP within the IF. IF at 5.5% of proteins and containing β-lactoglobulin gelled for longer heating time at 80°C. At similar rate of total WP denaturation at 67.5°C and 80°C, the protein composition of the heat-induced aggregates changed between formulas, protein concentrations and heating temperatures but disulfide bonds were the main intermolecular links. The aggregates were larger and of fractal shape (dfapp=2.1) in formulas at 5.5% proteins whereas they were of spherical shape (dfapp=2.9) in formulas at 1.3% proteins.These results will give to industrials reliable data on the protein structures formed during the heat treatments of IF. The impact on digestibility will be subsequently investigated

Righting a Wrong: Woodrow Wilson, Warren G. Harding, and the Espionage Act Prosecutions

International audienc

Contribution of temporal dominance of sensations performed by modality (M-TDS) to the sensory perception of texture and flavor in semi-solid products: A case study on fat-free strawberry yogurts

This study aimed to perform Temporal Dominance of Sensations by modality (M-TDS) combined with a multi-intake approach to investigate texture and flavor perception in semi-solid products. Trained panelists (n = 15) evaluated fat-free strawberry yogurts enriched with functional proteins involving texture modifications. As yogurt is a semi-solid product, its in-mouth residence time is short. A multi-intake approach was therefore expected to give more reliable information about the sensory properties perceived by panelists. The two modalities of texture and flavor were analyzed separately to characterize the effect of added proteins. Trials were made according to an experimental design with two factors (protein type and concentration) and three levels each. Different statistical treatments, taking or not the temporality of attributes into account, were performed on standardized and non-standardized data. The implementation of M-TDS was essential to highlight differences of flavor perception in addition to the more evident texture modifications. The study of sensory trajectories evidenced that texture modifications, induced by the use of different whey proteins, slightly modified the perception of flavor and sweetness. The global flavor perception of the samples varied with the number of spoons, which particularly impacted the taste attributes. This study highlighted the importance of using M-TDS when studying texture and flavor in semi-solid products, and the relevance of the multi-intake approach to characterize flavor perception. This methodology enabled panelists to evidence both marked texture differences and subtler flavor modifications, and these useful data were emphasized by combining different statistical treatments

HeteroProtein Complex coacervates: mechanisms and potential applications

The application of fundamental physicochemical concepts for rational design of functional assemblies from food proteins constitute a response to the growing trend toward the development of new and innovative food products and also an opportunity to generate new protein-based supramolecular structures with new applications. Because of their omnipresence in food systems and their biodegradability, proteins are the focus of many attempts for their use as building blocks for such supramolecular structures. Controlled self- co-assembly of proteins can generate a variety of supramolecular structures that vary in shape, size and density (fibrils, spherulites, nanotubes, etc). For instance, well-defined microspheres called heteroprotein complex coacervates (HPCC) can be formed by control mixing of oppositely charged proteins.1 The objective of our research is to understand the mechanisms behind HPCC process from initial spontaneous molecular interaction to micro-scale characterization. In this communication, we will summarize our results on several binary protein systems and will show that co-assembly of proteins into complex coacervates (Figure) is a generic process that is, de facto, independent of the proteinamino-acid sequence. We will report on the requirements that drive such spontaneous coassembly:protein conformational state and flexibility, molar stoichiometry, total protein concentration, charge anisotropy, etc. The Research challenges and the promising uses of HPCC in food and non-food sectors (encapsulation of bioactives, design of edible films) will be discussed

HeteroProtein Complex coacervates: mechanisms and potential applications

The application of fundamental physicochemical concepts for rational design of functional assemblies from food proteins constitute a response to the growing trend toward the development of new and innovative food products and also an opportunity to generate new protein-based supramolecular structures with new applications. Because of their omnipresence in food systems and their biodegradability, proteins are the focus of many attempts for their use as building blocks for such supramolecular structures. Controlled self- co-assembly of proteins can generate a variety of supramolecular structures that vary in shape, size and density (fibrils, spherulites, nanotubes, etc). For instance, well-defined microspheres called heteroprotein complex coacervates (HPCC) can be formed by control mixing of oppositely charged proteins.1 The objective of our research is to understand the mechanisms behind HPCC process from initial spontaneous molecular interaction to micro-scale characterization. In this communication, we will summarize our results on several binary protein systems and will show that co-assembly of proteins into complex coacervates (Figure) is a generic process that is, de facto, independent of the protein amino-acid sequence. We will report on the requirements that drive such spontaneous coassembly: protein conformational state and flexibility, molar stoichiometry, total protein concentration, charge anisotropy, etc. The Research challenges and the promising uses of HPCC in food and non-food sectors (encapsulation of bioactives, design of edible films) will be discussed

Mineral-binding peptides from food

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Biopeptides of milk: caseinophosphopeptides and mineral bioavailability

The biological and physiological activities of milk proteins are partially attributed to several peptides encrypted in the protein molecules. These peptides can be liberated by enzymatic digestion in vitro and in vivo. Among the biologically active molecules, phosphorylated peptides (caseinophosphopeptides, CPP) are known to exert an effect on calcium metabolism but also on other minerals. While the existing discrepancy on the potential role of CPP on calcium availability has not been clarified, the results of our previous studies showed that a purified phosphopeptide (β(1- 25)) exhibits a positive effect on iron bioavailability in vivo. Here we report the main results on the efficiency of β(1-25) in the absorption and availability of iron as well as on the mechanism involved.[br/