Teses / dissertações sobre o tema "Protéines de lait ¹⁵N"
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Benhaddou, Soukaïna. "Étude de la biodisponibilité digestive et métabolique des protéines alimentaires après bypass gastrique". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASB005.
Texto completo da fonteBariatric surgery stands as the most effective treatment for morbid obesity, with the Roux-en-Y Gastric Bypass (RYGB) being a commonly employed procedure. Its efficacy in weight loss and the reduction of comorbidities has been extensively demonstrated. Despite its frequent association with protein deficiency, the consequences of RYGB on the digestive and metabolic availability of proteins remain poorly understood. This thesis aims to assess the effects of RYGB on the digestive and metabolic fate of dietary proteins, using a test meal containing ¹⁵N labeled milk proteins in both rats and humans. Rats were monitored for 1 or 3 months post-RYGB to evaluate its mid-term effects on the intestinal mucosa, digestibility, and metabolic availability of dietary proteins. This study showed that protein digestibility was not altered by RYGB, even though the intestinal mucosa is hypertrophied. A transient decrease in nitrogen retention in peripheral organs and a persistent increase in deamination of dietary amino acids (AA) were observed. In humans, the metabolic fate of proteins was assessed one month before and six months after RYGB in 4 patients over 9 included (NCT04934826). Three of them exhibit a mild to marked increase in AA catabolism. RYGB induced variable modifications in dietary nitrogen metabolism among individuals. This thesis demonstrated that RYGB alters the metabolic availability of proteins, mainly through an increase in postprandial catabolism of AA. In addition to these studies, the development of small intestinal organoids of rats was conducted to mimic intestinal modifications after RYGB. The organoids exhibit substantial variability (size, shape, and gene expression), with no differences observed between those derived from control rats and RYGB rats
Espina, V. "Fractionnement de protéines du lait par filtration dynamique". Phd thesis, Université de Technologie de Compiègne, 2009. http://tel.archives-ouvertes.fr/tel-00433359.
Texto completo da fonteEspina, Perez Valentina Soledad. "Fractionnement de protéines du lait par filtration dynamique". Compiègne, 2009. http://www.theses.fr/2009COMP1820.
Texto completo da fonteThis thesis focuses on milk proteins fractionation by dynamic filtration. A two-stage process has been proposed in order to separate milk proteins into three main fractions: casein micelles, A-Lactalbumin and A-Lactoglobulin. The first stage of the process consists in microfiltration of skim milk for separating casein micelles from whey proteins. The performances of two dynamic filtration modules: the Multi Shaft Disk (MSD) module and the rotating disk module have been compared. The results have shown that the MSD module presents high permeate flux, good whey proteins transmission and high casein micelles rejection. The second stage of the process is the separation of A-Lactalbumin from B-Lactoglobulin by ultrafiltration. The rotating disk module equipped with a disk with vanes and rotating at 2000 rpm, was used. The protein transmission and selectivity were constant during whey concentration. This is an advantage of dynamic filtration because in crossflow filtration protein transmission and selectivity decreased during whey concentration. The selectivities obtained with dynamic filtration, without changes in pH and ionic strength of the solution, were in the same range as those obtained with crossflow filtration after pH and ionic strength optimization
Saint-Eve, Anne. "Compréhension de la libération et de la perception des composés d'arôme en condition de consommation : cas du yaourt brassé aromatisé". Paris, Institut national d'agronomie de Paris Grignon, 2006. http://www.theses.fr/2006INAP0026.
Texto completo da fonteMatringe-Brunold, Elisabeth. "Propriétés fonctionnelles des protéines de lait et d'oeuf et de leurs mélanges". Dijon, 1993. http://www.theses.fr/1993DIJOS069.
Texto completo da fonteZuñiga, de Lopez Raquel. "Étude structurale et texturale de laits acidifiés par hydrolyse de Glucono-Delta-Lactone et contenant des polysaccharides". Vandoeuvre-les-Nancy, INPL, 1999. http://www.theses.fr/1999INPL071N.
Texto completo da fonteSaint-Sauveur, Diane. "Propriétés immunomodulantes des protéines et peptides du lactosérum". Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26519/26519.pdf.
Texto completo da fonteChamoux, Muriel. "Étude des propriétés biologiques de l'angiogénine bovine et mise en évidence d'un récepteur sur les cellules endothéliales de capillaires". Lille 1, 1991. http://www.theses.fr/1991LIL10109.
Texto completo da fonteHélary, Mylène. "Caractérisation de l'effet satiétogène des protéines et macanismes impliqués : application aux protéines laitières". Paris, AgroParisTech, 2009. http://www.theses.fr/2009AGPT0073.
Texto completo da fonteGoussard, Christophe. "Intolérance aux protéines du lait de vache (IPLV): une solution diététique, le lait hypoallergénique (exemple Nidal HAo)". Paris 5, 1990. http://www.theses.fr/1990PA05P047.
Texto completo da fonteAndoyo, Robi. "Complexes thermo-induits de protéines de lactosérum : comment interagissent-ils avec la caséine dans les gels acides de lait ?" Rennes, Agrocampus Ouest, 2014. http://www.theses.fr/2014NSARB251.
Texto completo da fonteIn this project, we aimed at evaluating the role of physical factors, such as size and number of the denatured whey protein particles, on the acid gelation of skim milk model systems. To do that, two approaches were used, i. E. Varying the concentration, or the size of the particles using emulsification or microfluidics. Although concentration, size and number are somehow linked, our results showed that higher gel firmness is reached when connectivity is enhanced, i. E. When numerous particles are present; and in the case of mixtures with casein micelles, when enough particles are present to connect micelles together. The effect of size was less evident. Clearly, decreasing size leads to an increase in number and we indeed observed that small whey protein particles were forming gels with higher firmness. However, the effect was not linear, which suggested that a threshold value exists where the connectivity is not only low (due to a low number of particles) but maybe destroyed (due to hindrance of big particles in the gel). Although the denatured whey protein aggregates quantitatively affect the gel’s firmness and connectivity, the mechanism of gelation of model milk seemed to be essentially driven by the casein micelle, since the mixed gel had qualitatively the same scaling behavior than the pure casein. This is in agreement with the observation that whey protein aggregates preferably interact with the surface of the casein micelles, yielding “modified” casein micelles, with little or no side-interaction between the whey protein aggregates
Forkwa, Germaine Enyoh. "Boissons fermentées de type yogourt à boire enrichies en protéines de lactosérum et en probiotiques". Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27736.
Texto completo da fonteThe aim of this project was to develop new fermented milk beverages from whey protein concentrates with attractive sensory properties. Other desired characteristics for these beverages were high protein concentration, high probiotic content and no use of additives (sugar, polysaccharides, colorants, artificial flavors). These drinks would have potential benefits on cardiovascular health, body weight and the well-being of consumers. Beverages containing 10% whey protein were obtained by fermenting whey protein concentrates (WPC) and/or whey protein isolates (WPI). Ten WPCs and two WPIs were evaluated for their ability to allow lactic fermentation by 2 types of mesophilic starter cultures. The medium with the best fermentation kinetics and the best organoleptic properties was selected. The impact of 7 thermophilic starter and 2 probiotic cultures on cell concentration and stability, post acidification and organoleptic properties was studied. The fermentations were adapted to generate products with at least 1 to 10 billion probiotics per serving. This project allowed the development of fermented beverages (drinking yogurt type) with 10% whey proteins and 2 billion probiotic bacteria per mL, exclusively from whey derivatives. Each 100 mL serving contained 200 billion probiotics and would be considered as a product with the highest probiotics counts on the Quebec market. These results could lead to the marketing of new products with high growth potential that respond to several market trends in the health food sector.
Mahmoudi, Najet. "Impact de la structure sur les propriétés interfaciales d'agrégats de protéines globulaires du lactosérum". Nantes, 2007. http://www.theses.fr/2007NANT2102.
Texto completo da fonteWhey proteins are widely used in the food industry for their emulsifying and foaming properties. The thermo-mechanical treatment during processing leads to aggregate formation whose role in the stabilization of dispersed systems is still poorly understood. In the present work, whey protein isolates have been subjected to thermal treatments, with or without shearing, in order to generate different types of aggregates. We have shown by light scattering and small angle neutron scattering as well as by cryo-transmission electron microscopy that aggregates formed without mechanical treatment have a fractal structure. The size and the fractal dimension of these aggregates depend on the ionic force and the protein concentration for neutral pH. Under shear, spherical structures of nanometric size have been observed. With dynamic drop tensiometry, Langmuir film balance studies and AFM the air-water interfacial layers have been characterized for the different aggregates types. It could be shown that the tension and dilatational elasticity properties depend on the presence of isolated proteins as well as on the size of the objects and their internal cohesion
Morand, Marion. "Des complexes protéiques thermo-induits fonctionnels : quelles interactions établissent-ils dans un gel acide laitier ?" Rennes, Agrocampus Ouest, 2011. http://www.theses.fr/2011NSARI063.
Texto completo da fonteIn the context of the acid gelation of milk, it is known that the heat treatment of milk at 85-95°C during several minutes increases the pH of gelation and yields more homogeneous, more elastic acid gels that also present less expulsion of serum than unheated milk. These new properties are attributed to the formation of heat-induced protein complexes. According to a recent hypothesis, these complexes interact with the casein micelle during heating or acidification. They functionalize the micelle, by modifying the colloidal interactions that account for its stability. However, these interactions are still not fully identified. The objective of this study was to evaluate the relationship between the physico-chemical properties of the complexes and the nature of the interactions that are established during acidification. The role of κ-casein involved in these complexes, as well as the role of hydrophobic or electrostatic interactions were tested. According to an original approach, each of these properties was widely modulated, without changes of the other properties. The consequences of these changes on the formation of the acid gel were measured using rheometry and confocal laser scanning microscopy. It was shown that the heat-induced complexes impose their functional properties of acid gelation to the casein micelle. During acidification, the reduction of the electrostatic repulsions between the complexes allows the particles to connect and to establish attractive interactions that induce destabilization of the milk and construction of the acid gel. Among these attractive interactions, hydrophobic interactions play a major role. These results shall participate to clarify the mechanisms of formation of acid milk gels
Queguiner, Claire. "Nouvelles propriétés fonctionnelles de protéines laitières obtenues par traitements thermomécaniques d'extrusion". Montpellier 2, 1992. http://www.theses.fr/1992MON20271.
Texto completo da fonteBoutouili, Ghania. "Variations de la composition protéique et minérale du lait de vache : incidences sur les intéractions minéraux-protéines et la valeur technologique". Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPLA003.
Texto completo da fonteDa, Silva Pinto Michele. "Chauffage et glycation des protéines du lait : agrégation et digestion in vitro". Rennes, Agrocampus Ouest, 2014. http://www.theses.fr/2013NSARB236.
Texto completo da fonteMilk proteins are important for their nutritional value and for their functional properties. Heat treatment is commonly used in dairy technology and in some cases milk is submitted to cumulative heat treatments. However, behavior of protein during heating depends on the physico-chemical conditions and also on the presence of other molecules (sugar, protein and lipid). We hypothesized that in addition of the well- known β-lactoglobulin (β Lg) / κ-casein (κ-CN) complexes, other kind of aggregates occur in heated milk. To gain information of the occurrence of such species, the aim of this work was to study the effects of a strong heat treatment (90 ºC with different holding times) using following model systems: purified β Lg and β-casein (β-CN), in presence of a reducing sugar (glucose) at neutral pH heated up to 24 h; and β-Lg with other milk proteins: αS2 casein (αS2 CN) and κ-CN at neutral pH. Furthermore, we studied the consequences on the in vitro simulated digestion of the produced aggregates. To characterize aggregates formed during heat-treatment and their breakdown, we use a series of techniques: gel electrophoresis (LDS-PAGE), thioflavin T essay, transmission electron microscopy, size exclusion chromatography, fluorescence, dynamic light scattering and hydrolysis kinetics. Our results revealed that high temperatures have favored the formation of covalent bonds, others than disulphide. β Lg fibrils were produced at neutral pH and glucose decreased aggregate formation. On the other hand, glucose enhances β-casein aggregation. About digestion, when we consider only Maillard Reaction, we show that proteolysis was impaired by glycosylation. When β-Lg was heated with αS2-CN or κ-CN, we observed that homo- or hetero- aggregates were formed. Finally, the digestion of the mixed aggregates did not change when different proteins were heated together; even a slight increase of susceptibility to proteolysis was noted. These fundamentals studies highlighted some possible protein/sugar and protein/protein interactions during heat treatment, and give more details on the possible chemical transformations that occur during severe or cumulative heat treatments. Further, information about digestion of the aggregates may assist future studies about allergenicity or availability of milk proteins
Chevalier, Laura. "Étude des interactions entre les protéines de lactosérum et les fibres du bleuet dans la formulation d'aliments enrichis en fibres et en protéines". Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/30958.
Texto completo da fonteFiber and protein are two nutrients highly desired by health-conscious consumers, however they cause texture and instability problems in the food products in which they are incorporated. In mixed systems, these two macromolecules may form complexes by electrostatic associative interactions under certain well-known conditions but far from food matrices and industrial reality. To date, there has been very little work on the application of protein-polysaccharide complexes in food products. In this thesis, interactions between whey proteins and blueberry puree, more specifically pectin, were studied in order to form protein-pectin complexes improving the functional properties of foods and beverages enriched in fiber and proteins. Firstly, purees of several blueberry cultivars were characterized, in particular in terms of fiber and pectin contents. Two cultivars were selected for the further work, namely Patriot for its larger production in Quebec and Polaris for its fiber richness. It was shown that the degree of methylation (DM) of their pectin can be decreased (< 50%) by applying a low-temperature blanching (LTB) onto the puree. A lower DM corresponds to a higher overall charge density, which may improve the pectin affinity toward proteins Then, whey protein isolate was added to non-heated and heated (LTB + pasteurization) purees. This time, blanching did not reduce DM and heating resulted in the solubilization of highly methylated pectin (DM > 70%). Regardless of the cultivar, insoluble protein-pectin complexes were formed at the acidic pH of blueberry (pH 3.5) in the non-heated puree and contributed to increase the viscosity of the resulting mixtures. In the heated puree, the high DM of pectin and the higher amount of soluble pectin probably decreased the pectin affinity toward proteins and increased the stability of the complexes. The non-heated mixtures that contained complexes were used to formulate smoothies and bars rich in fiber and protein. The final pasteurization of the smoothies enhanced complexation and reduced their particle size, which helped for reducing their viscosity, compared to the smoothies without whey proteins. For bars, complexes increased their initial hardness in particular because of a slower solubilization within the matrix, compared to bars without complexes. However, they contributed to slow kinetics of hardening over time, explained by a better stability of bar water activity and probably by a decrease in protein aggregation. All of this work demonstrated that a matrix composed of proteins added to blueberry puree is a functional ingredient that may be readily incorporated into formulations to produce foods and beverages rich in fiber and protein. These results show that the complexes formed between the proteins and the pectin in a puree have a significant impact on the textural and rheological properties of these products. They provide an original approach and new support for the industrial development of functional foods and beverages enriched with both fiber and protein.
Canabady-Rochelle, Laëtitia. "Équilibre en calcium dans les systèmes lactés - Étude des interactions calcium-protéines". Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL016N.
Texto completo da fonteCa equilibrium between soluble and colloidal phases was studied in milky systems (milk, Non Hydrolysed, NH, or Hydrolysed, H, soy milks). Calcium chloride supplementation (CC, 25 mmoles.kg-1) was followed by pH cycle (pHmin 5.5 or 3.5). pH, Ca2+, turbidity and apparent viscosity were recorded in situ. Ca equilibria were related to protein phase variations. Contrarily to milk, Ca2+ concentration was initially negligible in soy milks. Yet, whatever the milky system, Ca2+ increased upon CC addition and with acidification, and decreased during alkalinization. For reference milk, pH cycle to 5.5 was reversible neither on Ca2+ variations nor on protein phase contrarily to CC-milk. This could be due to the previous capture of Ca during supplementation, involving casein micelles reinforcement through Ca-protein interactions. For pH cycle to 5.5, acid-induced aggregation was partially and completely reversible upon alkalinization for NH and H-soy milks, respectively. Once CC addition, Ca-induced aggregation was irreversible and pH cycle had minor effects. Whatever the system, the irreversibility of phenomena was observed for pH cycle to 3.5. Ca-(milk or soy) protein interactions studied by ITC showed similar endothermic signals, probably due to the water release occurring upon interaction. Ca binding should rather be described as H+/Ca2+ exchange with respect to the electrostatic forces involved. Finally, Ca-binding sites were identified with FTIR spectroscopy. A decrease of the absorption energy in the amide I and II region and in the carboxylate region occurred upon CC-addition, with higher variations in soy milks
Nicodème, Muriel. "Identification d'une souche de Pseudomonas, bactérie psychrotrophe isolée de lait cru : Caractérisation de sa protéase extracellulaire et des sites d'hydrolyses sur les caséines bovines". Nancy 1, 2006. http://www.theses.fr/2006NAN10056.
Texto completo da fonteMilk storage at refrigeration temperature permits the growth of psychrotrophic microorganisms, mainly belonging to the genus Pseudomonas that can generally produce heat-resistant extracellular proteases, causing milk proteolysis during storage. The proteolytic psychrotrophic strain isolated from raw milk, Pseudomonas sp. LBSA1 produces a unique caseinolytic extracellular protease with an apparent molecular mass of 49 kDa with milk addition. Different factors, such as temperature, agitation, and addition of many components can affect its production. A polyphasic taxonomic study of the LBSA1 strain reveals that it is phylogenetically related to the species P. Poae, but, it has an original siderovar and then it could belong to a new Pseudomonas species. The protease of the strain LBSA1 was purified, the corresponding gene was sequenced; the enzyme is identified as a zinc metalloprotease of the serralysin family (E. C. 3. 4. 24. 40). It is active under broad pH values and that optimal temperature for activity is nearly 40°C. The protease presented a low temperature inactivation around 45°C but it showed a greater stability around 60-80°C. The bovine caseins are rapidly hydrolysed by the enzyme without a real specificity but whey proteins are resistant to the action of the protease
Naveed, ul Haque Muhammad. "Production de protéines dans le lait en réponse à des profils en acides aminés intestinaux chez la vache laitière à différents niveaux d'apport de protéines digestibles dans l'intestin : Efficacité globale d'utilisation des protéines et des acides aminés". Rennes, Agrocampus Ouest, 2012. http://www.theses.fr/2013NSARB230.
Texto completo da fonteDecreasing the supply of protein truly digestible in the small intestine (PDI) to dairy cows is a way to reduce nitrogen excretion in environment however it also decreases milk protein yield without increasing PDI supply. This is evident in the studies where Lysine (Lys) and Methonine (Met) were balanced n high PDI diets. Beyond Lys and Met, literature to see the effects of balancing other EAA on dairy cow’s performance is limited. Further, literature is inconsistent to conclude whether balancing the supply of EAA in low PDI diets could be equally effective as it proved to be in high PDI diets. Our objectives in this thesis were : 1) to refine the proposed ideal requirements of other EAA and to compare the increase in PDI efficiencies when diets were balanced with 2 (Lys, Met), 3 or all 9 EAA ; and 2) to see whether balancing EAA profile increase milk protein yield similarly at low vs. High PDI based diets and how mammary metabolism modifies with these changes. The results of these studies validate following requirements for EAA in dairy cows : 2. 5 % of PDI for Histidine 8. 9% of PDI for Leucine, 5. 2 % of PDI for Phenylalanine. PDI quality of diet based on corn-silage and soybean meal should account for Lys, Met, Histidine and Leucine concentrations. Balancing EAA profile increased PDI efficiency of conversion to milk by 7%-8% similarly in low vs. High PDI based diets. The increase in milk protein yield is a function of EAA uptake by mammary gland. In conclusion this research clearly demonstrate that balancing EAA profile of diet is an effective mean of decreasing PDI intake while maintaining milk protein yield at a similar level observed by providing high PDI based diets
Perreault, Véronique. "Contribution à la compréhension de la fonctionnalité des protéines du lactosérum dénaturées dans la matrice fromagère". Doctoral thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27782.
Texto completo da fonteLa transformation du lactosérum de fromagerie en concentré de protéines du lactosérum dénaturées (CPLD), pour recyclage dans une production fromagère subséquente, est maintenant pratique courante dans l’industrie à grande échelle au Canada. Bien que les CPLD puissent être utilisés comme ingrédients de remplacement de la matière grasse, vu les coûts élevés de la protéine laitière dans le contexte canadien, l’emploi de CPLD vise parfois plutôt à substituer en partie la caséine du lait dans le fromage. Le CPLD ayant servi à réaliser le présent projet représente un CPLD conçu en milieu industriel dans cette optique. De façon générale, l’introduction de CPLD dans le lait de fromagerie est associée à une rétention d’eau accrue dans le fromage et à des changements de texture, mais les mécanismes responsables de ces phénomènes demeurent à clarifier. Cette thèse avait pour but d’étudier et expliquer les conséquences de l’addition de CPLD au lait de fromagerie sur les propriétés physico-chimiques des gels présure et mécaniques du fromage. Une première étude a permis d’évaluer l’effet combiné des niveaux de CPLD et de gras dans le lait de fromagerie sur ses propriétés de coagulation par la présure et la capacité de contraction du gel. L’augmentation du niveau de substitution des protéines du lait par des protéines du CPLD a résulté en une diminution du taux de coagulation et de la rigidité du gel (module d’élasticité - G), ainsi qu’en une diminution de la capacité de contraction du gel. Un effet direct du CPLD sur ces propriétés, au-delà d’un effet attribué à la dilution des caséines, a été mis en évidence. En outre, cette étude a permis de confronter l’effet des agrégats de protéines du lactosérum dénaturées, considérés comme éléments de remplissage des gels, à l’effet d’un autre type d’éléments de remplissage soient les gouttelettes de gras : à fractions volumiques équivalentes, les résultats ont montré des impacts distincts sur les propriétés mécaniques des gels. Une seconde étude a permis d’évaluer l’effet des différentes fractions du CPLD sur les propriétés de coagulation du lait par la présure et la capacité de contraction du gel. Le CPLD a été fractionné par centrifugation et dialyse en trois composantes : agrégats sédimentables, composante non sédimentable et composante diffusible. La composante diffusible (minéraux solubles) n'a pas affecté les paramètres de coagulation et de contraction. Les agrégats sédimentables de même que la composante non sédimentable ont influencé négativement les propriétés de coagulation ainsi que la capacité de contraction du gel. Les résultats ont notamment suggéré que des complexes protéiques solubles (non sédimentables et non diffusibles) retrouvés dans le CPLD puissent interagir avec les micelles de caséine emprésurées et limiter la formation et la contraction du gel. Une troisième étude a permis d’évaluer l'effet du CPLD et de ses fractions sur la composition et les propriétés mécaniques du fromage. La centrifugation a été utilisée pour induire un gradient d'humidité dans le fromage, afin d’isoler la contribution directe du CPLD et de ses fractions aux propriétés mécaniques du fromage. Le rendement et la teneur en humidité du fromage ont augmenté et la rigidité du fromage (module complexe - G*) a diminué avec l’augmentation du niveau de substitution des protéines du lait par des protéines du CPLD dans le lait de fromagerie. Cependant, pour des fromages ayant une même teneur en humidité, l’augmentation du niveau de CPLD n'a pas eu d'effet direct sur les paramètres rhéologiques. Les agrégats sédimentables ont été principalement responsables de l'augmentation du rendement fromager avec l’utilisation de CPLD. Dans l'ensemble, la teneur en humidité a expliqué en grande partie la variation des propriétés rhéologiques du fromage en fonction de la fraction de CPLD. Toutefois, en éliminant l'effet de l'humidité, l'addition des agrégats sédimentables du CPLD a conduit à une augmentation de la rigidité du fromage. Par la mise en évidence de l’effet distinct de chacune des fractions du CPLD, au cours de la transformation du lait en fromage, ces travaux ont conduit à l’identification de mécanismes d’action expliquant l’impact de l’introduction de CPLD dans le lait de fromagerie sur les propriétés des gels présure et du fromage : des connaissances en appui au développement de CPLD de haute performance en fromagerie et à l’amélioration de la qualité du fromage enrichi de CPLD.
Transformation of cheese whey into denatured whey protein concentrate (DWPC) for recycling into a subsequent cheese production is now common practice in large-scale industry in Canada. Although DWPC can be used as a fat replacer, considering the high cost of dairy protein in the Canadian context, DWPC is sometimes used as a substitute for milk casein in cheese. The DWPC used to carry out this project consists in a DWPC designed for this purpose in an industrial context. The introduction of DWPC into cheese milk is generally associated with increased water retention in cheese and changes in texture, but the mechanisms responsible for these phenomena remain to be clarified. This thesis was aimed at studying and explaining the consequences of the addition of DWPC to cheese milk on the physicochemical properties of rennet gels and mechanical properties of cheese. A first study evaluated the combined effect of DWPC and fat concentrations in milk on the rennet-induced coagulation properties and gel contraction capacity. The increase in the substitution level of DWPC proteins for milk proteins in cheese milk resulted in a decrease in coagulation rate and gel rigidity (elastic modulus - G), as well as a decrease in gel contraction capacity. A direct effect of the DWPC on these properties was demonstrated beyond an effect attributed to casein dilution. Moreover, this study allowed to compare the effect of denatured whey protein aggregates to that of fat globules, while both elements are considered to be fillers in rennet gels. For equivalent volume fractions, the results clearly showed different impacts of these fillers on gel mechanical properties. A second study evaluated the effect of different fractions from the DWPC on the rennet-induced coagulation properties and gel contraction capacity. The DWPC was fractionated by centrifugation and dialysis into three components: sedimentable aggregates, non-sedimentable component and diffusible component. The diffusible component (soluble minerals) did not affect coagulation and contraction parameters. The sedimentable aggregates and the non-sedimentable component both negatively influenced the coagulation properties as well as gel contraction capacity. The results suggested that beyond the effect of sedimentable whey protein aggregates, soluble proteinaceous complexes (non-sedimentable and non-diffusible) found in the DWPC could interact with the renneted casein micelles and limit gel formation and contraction. A third study evaluated the effect of DWPC and its fractions on the composition and mechanical properties of cheese. Centrifugation was used to induce a moisture gradient in the cheese to isolate the direct contribution of the DWPC and its fractions to the mechanical properties of cheese. Cheese yield and moisture content increased and cheese rigidity (complex modulus - G*) decreased when the DWPC was substituted for milk proteins in milk. However, for cheeses with the same moisture content, the substitution of DWPC proteins for milk proteins had no direct effect on rheological parameters. The sedimentable aggregates were primarily responsible for the increase in cheese yield with the use of DWPC. Overall, moisture content explained to a large extent the variation in cheese rheological properties depending on the DWPC fraction. However, when the effect of moisture was removed, the addition of the DWPC sedimentable aggregates to milk led to an increase in cheese rigidity. By demonstrating the distinct effect of each of the DWPC fractions during the processing of milk into cheese, this work led to the identification of mechanisms that explain the impact of introducing DWPC in cheese milk on the properties of rennet gels and cheese. These knowledges could support the development of high-performance ingredients that increase whey proteins recovery in cheese and could help to improve the quality of DWPC-fortified cheese.
Bouchard, Dominique. "Étude des fonctions d'une protéine à motif Whey Acidic Protein : la HE4 humaine". Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23850/23850.pdf.
Texto completo da fonteCasimir, Georges. "Contribution à l'étude de l'allergie aux protéines de lait de vache chez l'enfant". Doctoral thesis, Universite Libre de Bruxelles, 1990. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213101.
Texto completo da fonteNabhan, Mohamad Ammar. "Protéolyse et redistribution des protéines entre différentes fractions azotées après traitement du lait par hautes pressions". Vandoeuvre-les-Nancy, INPL, 2004. http://www.theses.fr/2004INPL054N.
Texto completo da fonteThe 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 alpha-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 55°C 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
Grandpierre, Catherine Bergonier. "Immunogénicité et antigénicité de produits de substitution dans les intolérances aux protéines de lait de vache". Toulouse 3, 1991. http://www.theses.fr/1991TOU30271.
Texto completo da fonteLajnaf, Roua. "Propriétés techno-fonctionnelles du lait de dromadaire". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT067.
Texto completo da fonteCamel milk proteins isolates, prior to foaming properties, were studied as a function of pH and temperature of heat treatment. The purity of the extracted camel α-lactalbumin (α-La) and β-casein was estimated by combining different analytical methods such as high pressure liquid chromatography (HPLC) and SDS-PAGE electrophoresis.The increased temperature treatment changed the foaming properties of camel α-La solution and its ability to unfold at the air/water interface. At neutral pH, heat treatment was found to improve foamability, whereas at acid pH (4.3) this property decreased. Heat treatment caused changes in α-La surface charge and free thiol group concentration, which confirmed the pronounced aggregation of heated camel α-La solution. Otherwise, the foaming and interfacial properties of extracted bovine and camel β-casein showed that at neutral pH, maximum of foam volume was achieved by both camel and bovine β-caseins. This property decreased at acid pH because of the casein precipitation and the lower surface protein coverage. Findings indicated also that varying pH affected the physicochemical properties of the bovine and camel β-casein solutions by decreasing the surface negative charge and intrinsic fluorescence. These results were more pronounced on the bovine β-casein suggesting a higher acid-sensitivity of this protein when compared to its camel counterpart.The second part of this work investigated the foaming and adsorption behavior of camel proteins mixed systems compared to bovine systems including whey fraction, sodium caseinates (Na-cas) and α-La/β-casein mixed systems at different ratios. The results showed that, acid wheys gave better foams when compared to sweet whey for both milks, with higher values for the camel whey. This behavior was explained by the proximity of the isoelectric point (pI) of whey proteins (4.9–5.2), where proteins were found to carry the lowest negative charge as confirmed by the zeta potential measurements. Unlike whey fraction, camel and bovine Na-cas exhibited lowest foaming and interfacial properties near its pI because of the casein precipitation. Whereas, created foams were more stable at pH 5 than at pH 7 especially after a heat treatment. The heat treatment of 70 °C and 90 °C during 30 min affected also the physicochemical properties of the bovine and camel Na-cas by decreasing intrinsic fluorescence confirming also the pronounced caseins precipitation at pH 5 where caseins were found to carry the lowest negative charge as found by the zeta potential measurementsMixed solutions of the two isolated camel proteins (α-La and β-casein) at different ratios (100:0; 75:25; 50:50; 25:75; 0:100) give more foam with a higher β-casein amount in all camel and bovine mixtures. Good correlation was observed with the adsorption and the interfacial rheological properties of camel and bovine protein mixtures. Thus, the proteins adsorbed layers are mainly affected by the presence of β-casein molecules, which are suggested to be probably the most abundant protein at interface and the most efficient in reducing the interfacial properties. Whereas, globular proteins such as α-La and β-Lg are involved in the protein layer composition but could not compact well at the interface to ensure foams creation and stabilization because of their rigid molecular structure.This work therefore suggests new alternatives for the production of foam from proteins derived from dromedary milk, a dairy product characterized both by a high biological value but also by interesting functional properties of its proteins, in particular their surfactant power
Gaaloul, Sami. "Étude de la gélification et de l'incompatibilité thermodynamique de mélanges de protéines de lactosérum/kappa-carraghénane sous cisaillement". Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26067/26067.pdf.
Texto completo da fonteLacroix, Magali. "Variations qualitatives & quantitatives de l’apport en protéines laitières chez l’animal & l’homme : implications métaboliques". Paris, AgroParisTech, 2008. http://pastel.paristech.org/5227/01/These-manuscrit.pdf.
Texto completo da fonteVidal, Véronique. "Influence des modifications chimiques des protéines du lait sur leur aptitude à la coagulation". Montpellier 2, 2000. http://www.theses.fr/2000MON20034.
Texto completo da fonteGeagea, Hany. "Contrôle des phages dans le lactosérum : étude de leur protection par les protéines sériques et identification d'un déterminant génétique responsable de leur résistance thermique". Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/28377.
Texto completo da fonteThe incorporation of whey protein concentrates (WPC) into cheese is a risky process due to the potential contamination with thermo-resistant phages of lactic acid bacteria (LAB). Furthermore, whey proteins can protect phages during heat treatment, thereby increasing the above risk. The objectives of this work were to understand this protective effect and to identify genetic determinant(s) responsible for the thermal resistance of lactococcal phages. First, the effect of pH and time of heating on the inactivation of lactococcal thermo-resistant phage P1532 (Sk1virus/936 group) was measured, at 95 ºC, in WPC and in three individual major whey components. The molecular structure changes of the tested proteins were also monitored by Fourier transform infrared (FTIR) spectroscopy. Phage inactivation results indicated that acidic conditions of WPC favor the destruction of dairy phages by heat treatment. Moreover, it revealed that the protective effect of whey proteins was pH and time dependent and was not restricted to one component. FTIR spectra suggest that the protection is related to protein molecular structures and to the level of protein aggregates. Then, to further investigate this protection, we used lactoferrin (LF) as a whey protein model as a result of its unique physicochemical properties. We combined FTIR and circular dichroism (CD) spectroscopies to monitor the structural conformational changes of LF. Phage inactivation results revealed a strong protective effect of LF on P1532 phage at pH 5 but none at pH 7. Spectroscopic analysis showed that LF was unfolded after heating at pH 7, while it preserved its tertiary and secondary structures when heated at pH 5. In sum, there is a direct correlation between the thermal stability of whey proteins and their ability to protect P1532 phage from heat treatment. The results obtained in this respect offer new tools to minimize the impact of the protective effect on lactococcal phages. In order understand the thermal resistance of LAB phages, we aimed to identify genetic determinant(s) responsible for the thermal resistance of lactococcal phages. After challenging CB14 heat-sensitive phage (Sk1virus/936 group) to low and high temperatures, two phages with increased thermal resistance were selected. Sequencing of their genome revealed a 120 bp deletion in the gene coding for the tape measure protein (TMP). The TMP protein sequences of mutant phages were compared with their homologues in other wild-type L. lactis phages with a wide diversity in heat stability. Comparative analysis of TMP proteins of other lactococcal phages identified the same deletions in the extremely heat-stable phages P680 and P1532. We propose that the TMP is, in part, responsible for the heat stability of the highly predominant lactococcal phages of the Sk1virus group. Identifying this genetic determinant for Sk1virus heat stability is a first step to understand the emergence of this group of thermostable phages, and may lead to improved control strategies in the cheese industry
Derisbourg, Pierre. "Etude des récepteurs entérocytaires de la lactotransferrine humaine : 1 - caractérisation des récepteurs des cellules entérocytaires humaines HT 29 : 2 - étude du mécanisme d'endocytose de la lactotransferrine". Lille 1, 1990. http://www.theses.fr/1990LIL1A002.
Texto completo da fonteColsenet, Roxane. "Étude par RMN de la diffusion moléculaire : influence de la structure des protéines laitières à l'état liquide et gélifié". Nantes, 2005. http://www.theses.fr/2005NANT2111.
Texto completo da fonteNasser, Sarah. "Evolution des propriétés structurales et fonctionnelles des poudres de PPCN en lien avec l’état initial et les conditions de vieillissement". Electronic Thesis or Diss., Lille 1, 2017. http://www.theses.fr/2017LIL10224.
Texto completo da fonteDuring storage, the functional (rehydration) and sensory (color) properties of the milk protein powders can alter, especially when the casein content of the powder is high. Understanding the mechanisms of structural changes at the molecular level that are at the origin of those property changes of casein-concentrated powders represents an important challenge for the dairy industry and hence the objective of this thesis. For this purpose, powders of micellar casein (MC) with or without lactose were stored up to 12 months at 4, 20, 40 and 60 ° C. Evolutions of secondary structures, compound migrations, chemical modifications as well as the evolution of functional and sensory properties were determined experimentally.The analysis of the results demonstrated the possibility to predict i) the ageing trajectory of the MC powders stored at ambient temperature by applying accelerated aging conditions; ii) the total rehydration time using the experimental tests that we proposed.The secondary structural changes at the origin of protein destabilization as well as different chemical modifications (acetylation, deamidation, lactosylation, dephosphorylation) were identified according to the composition. It was established that the aggregation of the caseins on the particle surface slowed down their dispersion into the aqueous medium, resulting in an increase of rehydration time. Finally, it has been established that the absence of lactose does not prevent protein destabilization or formation of insoluble matter, but it does prevent browning
Gelebart, Perrine. "Modulation de la texture des gels acides laitiers par addition d'agrégats de protéines laitières". Thesis, Nantes, 2019. http://www.theses.fr/2019NANT4018/document.
Texto completo da fonteThe texture of dairy products is a key parameter influencing consumer choices. In yogurt-type acid systems, the addition of milk protein aggregates would allow the development of products with innovative textures containing only dairy ingredients. The aim of this work is thus to highlight and understand the texturizing mechanisms of acidified models dairy emulsions through protein aggregates of different compositions, morphologies and sizes, by comparing them with conventional systems supplemented with whey proteins. For this purpose, fatty dairy gels acidified with GDL were manufactured by varying the concentration of different types of aggregates. The addition of whey proteins and fractal aggregates increases the strength of the gels and reduces their syneresis. Whereas the addition of compact spherical and mixed (casein-whey protein) aggregates does not modify the texture. Aggregates have a role in the continuous phase. The development of the interfacial surface by increasing the homogenization pressure and the fat fraction can allow the adsorption of aggregates at the interface of the fat droplets and increase the firmness. The nature of the aggregates influences interactions formed with the casein network during acidification. Among the interactions formed, disulphide bridges between whey proteins or fractal aggregates and the network were highlighted. The large variety of texture obtained in these systems demonstrates that it is possible to create innovative and specific products, especially protein-rich ones, to target certain types of population
Pichard, Patrick. "Effets des protéines de différents produits laitiers sur les concentrations sériques du cholestérol et des lipoprotéines chez le rat : valeur nutritionnelle de ces protéines laitières". Paris 7, 1985. http://www.theses.fr/1985PA07F095.
Texto completo da fonteCollard-Bovy, Christine. "Dosage des protéines du lait par immunonéphélémétrie sur supports microparticulaires : : Mise au point et applications". Nancy 1, 1988. http://www.theses.fr/1988NAN10491.
Texto completo da fonteRouy, Emilien. "Activité de peptides issus d’hydrolysats de protéines de lait sur la physiologie des cellules osseuses". Thesis, Paris, AgroParisTech, 2013. http://www.theses.fr/2013AGPT0085.
Texto completo da fonteOsteoporosis is a disease mainly affecting women after menopause, characterized by a reduced bone mineralization and a deterioration of bone micro-architecture. The aim of this thesis is to identify a milk protein fraction able to stimulate bone formation. When added to a food product, this fraction could reduce bone loss. The first task of this project was to produce the milk protein fractions. Milk proteins (casein or whey proteins) were digested by enzymes and fractionated by filtration according to their molecular weight. The fractions obtained were then tested on primary cultures of bone cells. Some of the milk protein fractions tested were able to increase proliferation and differentiation of osteoblasts. Among these active fractions, the one obtained by digestion of casein by chymotrypsin followed by filtration through a 10 kDa filter have been selected to be tested on animals. This fraction is named CR10. To study the activity of CR10 in vivo, a protein-restricted mouse model has been developed. Our studies showed that a reduction of protein in the diet from 20% to 6% impaired bone formation when the diet was based on soy protein. When these protein-restricted mice ingested the CR10 fraction, no improvement of the BMD was reported, which means that the CR10 cannot exert its anabolic activity in vivo. However, if casein is given instead of soy or if PTH is injected to the mice, bone formation is increased. These results suggest that the CR10 is not a good candidate as an anabolic fraction. However, the positive effect of casein compared to soy could be exploited in future studies aimed at finding an osteoanabolic casein fraction
Demers, Mathieu Véronique. "Activité antimicrobienne d'un extrait peptidique issus d'un hydrolysat trypsique de protéines de lactosérum". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28671/28671.pdf.
Texto completo da fonteGaschina, Winfried. "Fractionnement de mélanges de macromolécules par diafiltration : exemple d'application aux protéi͏̈nes du lactoserum". Toulouse 3, 1994. http://www.theses.fr/1994TOU30057.
Texto completo da fonteMéthot-Hains, Stéphanie. "Caractérisation de l'impact des conditions opératoires sur l'efficience d'un procédé de concentration du lait par ultrafiltration". Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26825.
Texto completo da fonteThe milk proteins concentrates are widely used as a dairy ingredient for cheese milk standardization. Milk protein concentrates are generally produced by ultrafiltration (UF) using polymeric membranes with molecular weight cut-off of 10 kDa, until a volume concentration factor of 3.5X. To improve the efficiency of the UF process, this study aimed at characterizing the impact of operating mode (constant transmembrane pressure (465 and 672 kPa) and constant flux) and temperature (10C and 50C) on the UF system performances during skim milk concentration until a volume concentration factor of 3.5X. A pilot-scale filtration module equipped with a 10 kDa polyethersulfone UF membrane with an effective surface of 2,04 m2 was used. System performance was characterized by the permeation flux, membrane selectivity and the total energy consumption. Experiments demonstrated that the permeation flux was 1,9 times higher at 50C compared to 10C. The protein rejection was not significantly affected by the transmembrane pressure and the temperature (P< 0,05). The temperature had an impact in terms of calcium content, which was 12% higher in the retentate generated at 50°C compared to the one produced at 10C. The total energy consumption was higher during UF at 10°C (0,32±0,02 kWh/kg retentate) compared to 50°C (0,26±0,04 kWh/kg retentate). The results showed that the energy efficiency ratio (ratio of the permeation flux and total energy consumption) was optimal at low constant transmembrane pressure and 50°C. The experimental approach developed in this project provides tools to dairy processors to improve the eco-efficiency of their membrane separation systems.
Abi, Azar Rania. "Complexation des protéines laitières par les extraits de gousses vertes de caroubier : propriétés technologiques des coagulums obtenus". Paris, AgroParisTech, 2007. http://www.theses.fr/2007AGPT0023.
Texto completo da fonteThe preparation of a traditional dairy product named mekika is well known in some specific areas of Lebanon. The mekika is produced by coagulating milk with green carob pods extract. Our study is done in the concept of preservation of the culinary traditions of the country by giving scientific information needed to support this product and allow its manufacture at industrial scale. Our objective is to study the chemical reactions implied in milk coagulation and the technological characteristics of the dairy product obtained. The importance of this traditional technology is assessed by its comparison with other practices using classical techniques for milk coagulation as for example proteolytic enzymes such as chymosin. This study is conducted also on different types of milk including cow, ewe, sheep and camel milk
Fairise, Jean-François. "Effets des traitements thermiques du lait de vaches sur la structure de l'édifice micellaire de caséines et conséquences sur la qualité des gels obtenus par acidification et emprésurage". Dijon, 1999. http://www.theses.fr/1999DIJOS038.
Texto completo da fonteN'Ngue, Marie-Andrée. "L'alpha-lactalbumine : susceptibilité à la protéolyse liée aux changements conformationnels induits thermiquement : Recherche de peptides à activité anti-oxydante". Nancy 1, 2006. http://www.theses.fr/2006NAN10051.
Texto completo da fonteThe structural modifications of bovine a-lactalbumin, known for its resistance toward proteases, were studied at various temperatures (from 25 to 70°C) by circular dichroism and by proteolytic approach using a thermostable enzyme, thermolysin (EC 3. 4. 24. 27). The various peptides produced during the hydrolyses were identified by mass spectrometry. A-Lactalbumin, resistant toward the hydrolysis at 25°C, becomes sensible from 40°C, because it adopts a molten globule-like state (MG) while preserving its chelated calcium. The MG-like state is the main form at 70°C and the protein is completely hydrolysed for 1 min of incubation at this temperature. The 1-58 amino-terminal and 95-123 carboxy-terminal regions of a-lactalbumin in its MG-like state are quickly hydrolysed by thermolysin, whereas the central region, which includes the binding site of calcium, is more resistant toward the hydrolysis at 70°C. Peptides with antioxidant activity have been identified in thermolysic hydrolysates from bovine and equine a-lactalbumins. Their concentration that decreases by 50% the concentration of the 2,2'-azinobis(3-ethylbenzothiazolin-6-sulfonic acid) radical cation is lower than 10 mM. These antioxydant peptides, that are homologous for the two species, are in general short and contain within their sequences one or two aromatic amino acid residues or a disulphide bridge. To conclude, the hydrolysis of a-lactalbumin at high temperature by a thermostable protease makes it possible to generate peptides with antioxidant activity
Nabil, Samira. "Étude de la digestion gastro-intestinale in vitro d'un ingrédient de protéines du lactosérum enrichi en facteurs de croissance". Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27491/27491.pdf.
Texto completo da fonteCharton, Elise. "Lait humain vs. préparation pour nourrissons : digestibilité des protéines et impact sur l’axe microbiote-intestin-cerveau". Electronic Thesis or Diss., Rennes, Agrocampus Ouest, 2023. http://www.theses.fr/2023NSARB368.
Texto completo da fonteNowadays, a high rate of infants is still being fed infant formulas (IF) based on cow milk and subjected to several technological treatments. These substitutes aim to mimic as close as possible the human milk (HM). Despite of IF improvement, differences still exist between HM and IF in terms of composition and structure, and effects on health in infancy, and later on in adulthood. The objective of this work was to understand how the infant food modulated the dietary nitrogen digestibility and, in overall, how it shaped the microbiota-gut-brain axis. Two infant models were used and compared, the 16 to 21-day-old mini-piglet Yucatan and an in vitro dynamic digestion model parametered with term infant digestive conditions. Digestive contents and tissues were then analyzed using metagenomic (microbiota), histological and ex vivo permeability (intestinal physiology) approaches, gene expression and targeted-metabolomic approaches (intestine, brain and plasma). The results showed that the digestibility of nitrogen and at least extent, that of a few amino acids (Lys, Phe, Thr, Val, Ala, Pro and Ser) were different between HM and IF. The two digestion models (in vivo and in vitro) led to similar observations in terms of meal deconstruction and proteolysis, showing that the in vitro dynamic digestion model is a good proxy of the in vivo digestion regarding digestion kinetics. The microbiota-gut-brain axis, notably regarding the colonic microbial composition and the tryptophan metabolism, which digestibility was similar between infant foods, were differently modulated by HM and IF. The increase of the intestinal permeability, though moderately, was associated with a boost of the intestinal immune system and changes in gene expression (barrier and endocrine functions, volatile fatty acids receptors) at hypothalamic and striatal levels and with changes in hippocampal and plasma metabolomic profiles. Some components present in HM (e.g.: oligosaccharides, non-protein nitrogen such as urea, bacteria consortia) and absent in IF can explain the discrepancies observed. IF-supplementation with these bioactive components and/or with the modulation of the protein profile would be of interest for further investigation
El-Zahar, Khaled. "Étude des protéines du système laitier ovin et de leurs transformations par hydrolyse et par fermentation lors de la fabrication des yaourts". Nantes, 2004. http://www.theses.fr/2004NANT2016.
Texto completo da fonteFour set of starters have been used for the fabrication of yoghurts from ovine milk pre-heated in different conditions. The degree of hydrolysis of caseins and whey proteins depended on the starter used. During fermentation, -casein was more hydrolysed than S-caseins; -lactalbumin (ALA) was more degraded than -lactoglobulin (BLG). -lactalbumin and -lactoglobulin have been obtained in a pure form by anion-exchange chromatography. -lactoglobulin was a mixture of A and B variants. -lactalbumin was obtained as an unique variant. -lactoglobulin was monomeric at acid pH and low ionic strength but became dimeric at neutral pH. At the opposite of its bovine counterpart, ovine -lactoglobulin was susceptible to pepsinolysis. Peptic hydrolysates of whey proteins showed an antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus
Rusu, Daniel. "Mécanismes d'action d'un extrait protéique du lactosérum bovin sur les fonctions du neutrophile humain". Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/26585/26585.pdf.
Texto completo da fonteSchouler, Catherine. "Caractérisation immunogénétique du bactériophage virulent phi 197 de Lactococcus lactis". Toulouse 3, 1992. http://www.theses.fr/1992TOU30078.
Texto completo da fonteNuyts-Petit, Véronique. "Influence des variants génétiques des caséines bovines sur l'aptitude fromagère du lait de vaches de races traditionnelles". Compiègne, 1991. http://www.theses.fr/1991COMPD398.
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