The effect of ultra-high temperature processing by direct steam injection and room temperature storage of pH-adjusted and unadjusted 3X (volume reduction) skim milk retentate and the effect of storage at various temperatures of 3X skim milk retentate without pH adjustment on their ζ-potential, viscosity, and pH were determined. Pasteurized skim milk was concentrated to 3X by ultrafiltration. In the pH study portions of skim milk retentate were adjusted to pH 6.38 ± .02 with HCl and 6.85 ± .01 and 7.32 ± .02 with NaOH between ultrafiltration and ultra-high temperature processing. In the storage temperature study, storage temperatures used for pH-unadjusted retentate samples were 11°C, 23°C (room temperature), and 37°C. Although pH 6.38 samples had the lowest viscosity in the pH study before ultra-high temperature processing, these samples precipitated during ultra-high temperature processing. For non-acidified samples, increasing pH of retentate resulted in higher viscosities and quicker age gelation times. Destabilization occurred more rapidly at 37°C than at 23°C or 11°C. The pH drop tended to be greater for samples stored at a higher temperature or adjusted to a higher pH. During 28 weeks of 37°C storage the pH decreased from 6.54 to 6.06. During 32 weeks of 23°C storage pH of samples initially adjusted to pH 7.32 dropped to 7.06. ζ-Potentials of casein micelles were calculated from electrophoretic mobility obtained by measuring Doppler frequency shifts of scattered laser light in samples that had been diluted 300 fold with their own ultra.filtrate. Absolute values of ζ-potential of samples stored at 37°C decreased from -23.4 millivolts immediately after ultra-high temperature processing to -18.5 millivolts after 28 weeks of storage. For samples stored at 11°C and 23°C in the storage temperature study and control samples in the pH study, absolute values of ζ-potential decreased approximately 1.5 to 2.0 millivolts during 28 or 32 weeks of storage.

Une triple attente socio-économique dans les domaines du développement durable (réduction des matières synthétiques non biodégradables), des solutions naturelles de conservation des aliments (tendance du « clean label » par la protection des denrées par des emballages actifs et intelligents évitant des additifs à outrance dans les aliments) et de la sécurité alimentaire (sécurité microbiologique et traçabilité) est à l’origine du développement de nouveaux matériaux à la fois biodégradables, comestibles et fonctionnalisés. Cette recherche commencée quelques décennies plus tôt est freinée par un mode de production difficilement industrialisable (voie solvant). Cependant, depuis quelques années des procédés applicables à l’échelle industrielle sont développées (voie fondue/extrusion). Dans le travail présenté ici, la technologie d’extrusion bivis a été appliquée avec succès sur différentes matières premières protéiques : la caséine acide, la caséine présure et le caséinate de sodium. Extraites toutes trois du lait de vache, ces caséines montrent des caractéristiques différentes qui affectent les propriétés du matériau (mécaniques, sensibilité aux molécules d’eau). La fonctionnalisation de la matrice par l’ajout d’acides organiques offre un potentiel antimicrobien intéressant contre Escherichia coli. Une complexation supplémentaire du matériau par incorporation de molécules hydrophobes telles que des cires (cires d’abeille, de candelilla et de carnauba) permet d’élargir une fois de plus l’éventail des propriétés disponibles pour ces matériaux composites, comme l’amélioration de la propriété barrière à la vapeur d’eau apportée par la cire d’abeille. La sensibilité aux molécules d’eau de ce type de matériau étant un critère à considérer à chaque étape de développement et de compréhension des interactions inter-ingrédients (protéine, plastifiant, cires, composés antimicrobiens). Ce manuscrit expose le potentiel de développement de matériaux à base de caséine, biodégradables, comestibles et antimicrobiens, qu’il s’agit d’appliquer en emballage agroalimentaire tout comme dans bien d’autres secteurs / Development of innovative biodegradable, edible and functionalized material comes from a triple socio-economic expectation in the field of sustainable development (decrease in synthetic non-biodegradable polymers), of natural solutions for food preservation (trend of “clean label” by food protection through active and smart packaging to avoid over-use of food additives) and of food safety (microbiological safety and traceability). Development in that field, started few decades ago is slowed down by production process (wet process), which is not an easy scale up process. However, a few years ago industrial process technique as extrusion started developing. In the present work, the twin-screw extrusion process was successfully applied to produce polymer based on protein raw material: acid casein, rennet casein and sodium caseinate. Extracted from caw milk, these three caseins own different characteristics, which affect material properties (mechanical, water sensitive properties). Matrix functionalization through organic acid addition bring an interesting antimicrobial response against Escherichia coli. Blending hydrophobic molecules as waxes (beeswax, candelilla wax and carnauba wax) creates a complex composite material which increases the range of available properties as improved water vapor barrier allowed by beeswax addition. Water sensitive properties are key points to consider at each step of material development and to understand relationships between the different ingredients (protein, plasticizer, waxes, antimicrobial agents). This manuscript shows the feasibility in the development of casein based material as biodegradable, edible and antimicrobial material, to apply and use in the food packaging industry or other industries

A primary emulsion with whey protein isolate (WPI) and hexanoic acid was prepared, and chitosan (Ch) (0.01%, 0.02%, and 0.03%) was added to evaluate its impact on particle size distribution of the emulsion. NaCl (0, 20, 40, and 80 mM) was added to increase ionic interactions to stabilize the multilayer emulsion. Lecithin (0.5%, 1%, 2%, 3 %, w/v) was mixed with the primary emulsion in order to form a multilayer, and casein hydrolysate (CH) was used to stabilize the tertiary emulsion system without the use of NaCl for 28 d at 4 °C. Stable O/W nanoemulsions were generated for use as nano-vesicular vehicles (NVV) to carry Curcumin (CU). Two important variables, (1) addition of casein hydrolysate (CH) (1:50, w/w WPI) and, (2) use of high pressure (140 and 210 MPa), were studied for their effect on the stabilization of monodispersed NVV and persistence of antioxidant activity of the CU as cargo in the NVV throughout storage. Addition of CH reduced nano-particle size and increased emulsion stability with UHPH pressure. The nanoparticle distribution was not changed by the addition of CU. Addition of casein hydrolysate reduced particle size as well as enhanced the positive functional properties of the NVV. Similar trends were observed in zeta-potential, surface energy, contact angle and antioxidant efficacy of the NVV, both with and without CU when UHPH was applied. The effect of Ultraviolet (UV) radiation (254 nm) on the stability of O/W nanoemulsion systems was investigated. A nano vesicular vehicle (NVV) was generated using ultra-high pressure homogenization (UHPH) that was stabilized using whey protein isolate (WPI) (1%, w/v), Tween 20 (20% w/w WPI) and casein hydrolysate (CH) (1:50 of WPI, w/w). Coarse emulsions were prepared by blending for three min. The coarse emulsion was exposed to UV radiation (0-60 min), followed by a single-pass of UHPH at 140 and 210 MPa. The UHPH treated NVV-CU had greater (P<0.05) short and long term antioxidant properties. After 28 d of storage, the CU-NVV treated at 210 MPa retained 7.0 and 1.4% greater AA and AP, respectively, when compared to the unpressurized CU-NVV.

Disease development of wild-type and Rag1 mutant zebrafish was evaluated after challenge with Snakehead Rhabdovirus (SHRV), a novirhabdovirus. Rag1 mutants lack T and B lymphocytes and thus lack lymphocyte-based acquired immunity. Wild-type zebrafish became more disease resistant as they aged (4 months and older) and at an elevated temperature (28°C) but mutants remained sensitive at all ages and temperatures tested. Quantitative reverse transcription polymerase chain reaction (RT qPCR) demonstrated that interferon gamma and MxA expression significantly increased in both types of fish at 2 days post-infection with subsequent dwindling of expression. The high interferon gamma expression suggests activation of natural killer cells (and/or T lymphocytes in wild-type fish), and the up-regulation of MxA expression indicated an activation of type 1 interferon response. The development of protection in virus exposed fish was evaluated by lethal challenge at 3 weeks post vaccination. Vaccinated wild-type fish showed significant protection and while most of the mutant groups showed no protection. One vaccination treatment group of the mutants demonstrated a significantly slower mortality and less overall mortality. The results suggest that lymphocyte based immunity imparts a robust protective response to SHRV while low-level protection can develop in the absence of lymphocytes. A cell mediated cytotoxicity assay was established. Cell lines were developed from the inbred fish populations and class I MHC U lineage genes were compared. The mhc1uba and mhc1uca genes were found in the mutant and cells but no class I MHC U lineage genes were detected in the wild-type fish or cells. These cells were used as targets in cytotoxicity assays. Kidney-marrow cells of vaccinated mutant or wild-type zebrafish killed more SHRV infected target cells than did those from non-vaccinated fish with the wild-type effectors showing higher cytotoxicity. The lymphocyte component appears responsible for the temperature and age associated resistance. This helps explain why novirhabdoviruses cause higher losses in young fish and at low temperatures. Further studies are needed to understand the relative contribution of the cellular components that play important role in SHRV resistance, but the establishment of cytotoxicity assays is an important first step in dissecting the cellular defenses in zebrafish.

Migraine is a common, episodic neurological disorder that includes headache, nausea and hypersensitivity to sensory stimuli. During the headache phase of migraine, migraine patients can be especially hypersensitive to thermal stimuli. The unpredictable and episodic nature of migraine makes it difficult to treat and much of the mechanism of migraine has yet to be elucidated. A T44A substitution in casein kinase 1δ is inherited with migraine with aura. A transgenic mouse model suggests that animals with this mutation exhibit increased sensitivity to thermal stimuli after injection with nitroglycerin (NTG). We performed behavior assays that measure animal responses to thermal stimuli, after injection with NTG, a known migraine-inducer in human migraine patients. Female animals with the CK1δ-T44A mutation are more sensitive than wildtype littermates, suggesting a sex difference emerges in pain sensitivity in animals that express the CK1δ-T44A but not in wildtype siblings. Female CK1δ-T44A animals are more sensitive to the effects of NTG on pain than male CK1δ-T44A mice. This indicates a potential sex hormone related pain response. Since estrogen is implicated in both migraine and pain response, we test the thermal sensitivity of heterozygous ERβKO/+ and CK1δ-T44A; ERβKO/+ mice compared to wildtype and CK1δ-T44A mice. Overall thermal sensitivity is decreased before stress of injection in both male and female ERβKO/+ and CK1δ-T44A: ERβKO/+ mice. This demonstrates that ERβ is necessary for thermal nociception in untreated mice. However, after injection with saline or NTG, animals of all genotypes responded to thermal stimuli similarly. This suggests that estrogen signaling through ERβ is likely not part of the pathway of NTG-induced thermal sensitivity or that one copy of ERβ is sufficient for NTG-induced thermal sensitivity. Since ERβ is fully functional in CK1δ-T44A mice and CK1δ-T44A mice have wildtype thermal sensitivity at baseline, we can conclude that CK1δ-T44A does not modulate ERβ to affect thermal sensitivity in untreated animals.

The kinetics of milk coagulation are complex and still not well understood. A deeper understanding of coagulation and the impact of the relevant factors would aid in both cheese manufacturing and also in determining the nutritional benefits of dairy products. A method using confocal microscopy was developed to follow the movement of milk fat globules and the formation of a milk protein network during the enzyme-induced coagulation of milk. Image processing methods were then used to quantify the rate of coagulation. It was found that the texture of the protein network is an indicator of the current status of the milk gelation, and hence can be used to monitor the coagulation process. The imaging experiment was performed on milk gels with different concentrations of the coagulation enzyme, chymosin. Rheological measurements were taken using free oscillation rheometry to validate the imaging results. Both methods showed an inverse relationship between rennet concentration and the coagulation time. The results from the imaging study were used to create a computational model, which created simulated images of coagulating milk. The simulated images were then analyzed using the same image analysis algorithm. The temporal protein network texture behavior in the simulated images followed the same pattern as the protein texture in the confocal imaging data. The model was developed with temperature and rennet concentration as user inputs so that it could be implemented as a predictive tool for milk coagulation.

Caseinate powders have been well accepted because of their foaming properties. In this study, 10% solution of reconstituted skim milk powder (SMP) chelated with sodium hexametaphosphate (SHMP) and trisodium citrate (TSC) at 1 mEq, 50 mEq, and 100 mEq were prepared to conduct a comparison with sodium caseinate, potassium caseinate, and calcium caseinate solutions. Foamability, foam stability as well as the preferential locations of αs-casein, β-casein and !-casein in their foams were analyzed. It was hypothesized that the foamability, foam stability and the preferential locations of these three caseins in the milk foams are different from treatment to treatment. Milk foam was generated with an air- injection method at a flow rate of 0.30 L/M for 18 seconds. Foam stability was measured through half-life method. The foam composition was quantified with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method. Analysis of Variance (ANOVA) test results concluded that there were no significant differences detected in foamability (p>0.05). On the other hand, foam stability differed significantly among the treatments. Foams of reconstituted SMP-treated with 1 mEq SHMP and TSC were significantly more stable compared to other treatments (p < 0.05), β-casein (p>0.05) and !-casein (p>0.05). In conclusion, the addition of calcium chelating salts might increase the foamability to the same level as caseinate solutions. Furthermore, the study proved that the combination of calcium chelating salts and chelator levels is able to alter the foam stability.

No description available.

<p> Protein digestibility, a function of the source of amino acids consumed, can differentially affect postprandial protein anabolism at rest. We investigated the effect of ingesting whey and casein proteins, in isolation and in combination, after an acute bout of unilateral resistance exercise on muscle protein synthesis in eight healthy resistance trained men (24.4 ± 4.8 yr; 177.4 ± 4.2 cm; 85.5 ± 14.8 kg; means± SD). On three occasions, participants performed a unilateral bout of resistance exercise following which they consumed a drink containing whey, whey and casein (1:1), or casein protein. Each drink provided 10 g of essential amino acids. Mixed muscle protein fractional synthetic rate (FSR) was determined by pulse-tracer injections of L-[ring-2H5]phenylalanine and L-[15N]phenylalanine 120-180 min after protein ingestion. The pattern of amino acid appearance in the blood after consuming the protein drinks was not different. Consequently, while consumption of the protein drinks stimulated a larger increase in FSR in the exercised leg compared to the rested leg (p < 0.05), there were no differences between the drinks. Thus, while the source of amino acids may affect protein turnover at rest, this effect is not apparent after resistance exercise. Therefore, we conclude that the ingestion of whey and casein proteins, in isolation or combination, stimulates mixed muscle protein synthesis to similar degrees after an acute bout of resistance exercise.</p> / Thesis / Master of Science (MSc)

Im Rahmen dieser Arbeit ist es durch die kombinierte Anwendung von P-31 Flüssigkeits (HR)- NMR-Spektroskopie sowie dynamischer Lichtstreuung (DLS) gelungen, die supramolekulare Struktur von mizellarem Casein aus ultrahocherhitzter (UHT) Milch unter dem Einfluss einer enzymatischen Vernetzung mittels mikrobieller Transglutaminase (mTG) zu charakterisieren. Die P-31 HR NMR-Spektroskopie erweist sich dabei als hervorragende Methode, um sowohl den Einbau von Casein aus dem Milchserum in die mizellaren Aggregate durch die enzymatische Reaktion als auch die bevorzugte mTG Vernetzung des beta-Caseins nachzuweisen. Durch die Kombination von P-31 HR NMR-Spektroskopie und Messungen der dynamischen Lichtstreuung war es weiterhin möglich, das Vorliegen vernetzter Caseinaggregate in Dispersionen mTG-behandelter Caseine zu belegen und besonders den Anteil an nicht vernetztem Casein „sichtbar“ zu machen, der durch EDTA-Zugabe aus den mTG-vernetzten Caseinnetzwerken freigesetzt wird. Es zeigt sich, dass die Caseinnetzwerke nach der EDTA-Behandlung eine geringere Proteindichte als mizellares Casein aufweisen, da sie nur ca. 20 % des Serinphosphats des mizellaren Caseins enthalten. P-31 Festkörper-NMR-spektroskopische Messungen legen außerdem nahe, dass die Beweglichkeit des phosphorylierten Ser149-Restes des kappa-Caseins in der äußeren Schicht der mizellaren Caseinaggregate durch die mTG-Behandlung nicht wesentlich verändert wird. Um die erhaltenen Caseinnetzwerke im Hinblick auf ihr Anwendungspotential zu untersuchen, wurden sie als Proteinkomponente bei der biomimetischen Calciumphosphatfällung sowie als Trägerstrukturen für bioaktives Lysozym verwendet. Durch den Einsatz von Caseinnetzwerken als Fällungsmedium während der Präzipitation von Calciumphosphat (CaP) ist es gelungen, eine hydratisierte, apatitische Phase zu stabilisieren, die sowohl ungeordnete als auch kristalline Bereiche enthält und damit strukturelle Ähnlichkeit zu biologisch und besonders biomimetisch gebildetem Apatit besitzt. Die in den Präzipitaten ebenfalls vorhandenen Phosphoratome in einer relativ ungeordneten OCP (Octacalciumphosphat)-ähnlichen Umgebung stehen höchstwahrscheinlich mit der apatitischen Phase in räumlich engem Kontakt und sind damit entweder Bestandteil dieser Phase oder befinden sich in einer getrennten Phase, die jedoch mit der apatitischen Phase in Form eines Nanokomposits mit sehr kleinen, eng benachbarten Kristalliten vorliegt. Bei der Fällung des Caseinnetzwerk/CaP-Präzipitats wird ebenfalls eine Dicalciumphosphat-Dihydrat (DCPD)-Phase gebildet. Diese ist separiert von den anderen CaP-Phasen und tritt in wesentlich geringerem Maße auf als in einem reinen CaP-Präzipitat, das ohne Proteinkomponente gefällt wurde. Damit konnte gezeigt werden, dass unter Bedingungen, bei denen ohne Proteinkomponente größtenteils DCPD entsteht, die Caseinnetzwerke eine apatitische Phase stabilisieren, die strukturelle Ähnlichkeit zu biologisch und biomimetisch gebildetem Apatit aufweist. Die qualitativ gleichen Ergebnisse konnten für vergleichsweise untersuchtes unvernetztes Casein gefunden werden. Die Caseinnetzwerke zeigen jedoch in Bezug auf die apatitische Phase einen stärkeren Stabilisierungseffekt als unvernetztes Casein. Es ist denkbar, dass dies unter anderem darauf zurückzuführen ist, dass die Phosphatzentren in den Caseinnetzwerken im Gegensatz zu Casein frei von CaP-Brücken sind, da diese durch die EDTA-Behandlung entfernt wurden. Da die Caseinnetzwerke zudem eine geringere Proteindichte und damit eine höhere „Porosität“ als die mizellaren Caseinaggregate aufweisen, kann sich die apatitische Phase möglicherweise auch innerhalb der Netzwerke bilden, während dies für die mizellaren Caseinaggregate wahrscheinlich nur begrenzt möglich ist. In der vorliegenden Arbeit konnte ebenfalls gezeigt werden, dass sich Caseinnetzwerke grundsätzlich als Transportsysteme für Lysozym eignen, da sie eine hohe Stabilität aufweisen und erfolgreich mit Lysozym beladen werden können. Während die Assoziation von Lysozym mit mizellaren Caseinaggregaten, die aus UHT-Milch gewonnenen wurden, zu einem fast vollständigen Verlust der Lysozymaktivität führt, bleibt die Aktivität des Enzyms bei der Bindung an Caseinnetzwerke erhalten. Das Anwendungspotential der Caseinnetzwerk/Lysozym-Assoziate wurde im Rahmen von zahnmedizinischen Versuchen in vitro und in situ untersucht. Es konnte nachgewiesen werden, dass die Caseinnetzwerk/Lysozym-Assoziate in vitro eine dauerhafte Immobilisierung des Lysozyms in der in situ gebildeten Pellikel bewirken. Eine deutliche Anreicherung des Enzyms in situ wird mithilfe der Caseinnetzwerke allerdings nicht beobachtet. Dies könnte darin begründet sein, dass die im Vergleich zu den in vitro vorgefundenen Verhältnissen deutlich komplexeren Bedingungen in situ zu einem selektiveren Anreicherungsprozess von Enzymen in der Pellikel führen.