Types Of Casein Research Articles

Antiseptic-Loaded Casein Hydrogels for Wound Dressings

Chronic wound treatment accounts for a substantial percentage of the medical expenses worldwide. Improving and developing novel wound care systems can potentially help to handle this problem. Wound dressings loaded with antiseptics may be an important tool for wound care, as they inhibit bacterial growth at the wound site. The goal of the present work was to investigate the potential of using casein hydrogel dressings loaded with two antiseptic drugs, Octiset® or polyhexanide, to treat chronic wounds. Casein-based hydrogels are inexpensive and have several properties that make them suitable for biomedical applications. Two types of casein were used: casein sodium salt and acid casein, with the formulations being labelled CS and C, respectively. The hydrogels were characterised with respect to their physical properties (swelling capacity, water content, morphology, mechanical resistance, and stability), before and after sterilisation, and they showed adequate values for the intended application. The hydrogels of both formulations were able to sustain controlled drug-release for, at least, 48 h. They were demonstrated to be non-irritant, highly haemocompatible, and non-cytotoxic, and revealed good antimicrobial properties against Staphylococcus aureus and Pseudomonas aeruginosa. Steam-heat sterilisation did not compromise the material's properties. The in vivo performance of C hydrogel loaded with Octiset® was evaluated in a case study with a dog. The efficient recovery of the wounds confirms its potential as an alternative for wound treatment. To our knowledge, this is the first time that wound dressings loaded with Octiset®, one of the most efficient drugs for wound treatment, were prepared and tested.

Efficiency of High-Frequency Pressing of Spruce Laminated Timber Bonded with Casein Adhesives.

This study identifies the importance of reducing press times by employing high-frequency pressing of spruce-laminated timber bound with sustainable casein adhesives. Spruce lamellas with dimensions of 12 × 10 × 75 cm were bonded into five-layered laminated timber and then separated into single-layer solid wood panels. Three types of casein (acid casein from two sources and rennin) were used. To compare the effectiveness of the casein formulation, two control samples bonded with polyvinyl acetate (PVAc) adhesive were pressed at room temperature (20 °C) and also with high-frequency equipment. The tests included compression shear strength, modulus of rupture, modulus of elasticity and screw withdrawal resistance on the wood panel surface and in the glue line. The average values of casein-bonded samples compression strengths ranged from 1.16 N/mm2 and 2.28 N/mm2, for modulus of rupture (MOR) were measured 85 N/mm2 to 101 N/mm2 and for modulus of elasticity (MOE) 12,200 N/mm2 to 14,300 N/mm2. The screw withdrawal resistance (SWR) on the surface of the wood panels ranged from 91 N/mm to 117 N/mm and in the adhesive line from 91 N/mm to 118 N/mm. Control samples bonded with PVAc adhesive did not perform better for compression shear strength, MOR and MOE, but for SWR in the adhesive line with 114 N/mm. Casein-bonded spruce timber pressed with HF equipment represents a sustainable new product with reduced press times, hazardous emissions and improved workability.

Assessment some Function Properties of Acid Casein in Different Types of Milk

The present work has been carried out mainly to study some functional testing such as solubility and foaming properties in four types of acid caseins Buffalo, sheep, goat and camel at different pH value ranging between 2- 8. The obtained result revealed that high solubility for all types of acid casein was at pH 2 and pH 8 except in acid sheep casein was at pH 5. Also, foaming expansion value for all acid casein was high at pH 2 and pH8. The obtained results concluded that foaming properties increased with increasing the solubility of all types of acid casein.

Characterization of the in situ pellicle ultrastructure formed under the influence of bovine milk and milk protein isolates

ObjectivesThe present study aimed to investigate if bovine milk or milk protein isolates, respectively, alter the ultrastructure of thein situ pellicle and might therefore have an influence on oral health. MethodsIn situ pellicle samples were formed on bovine enamel slabs exposed in the oral cavity of three subjects for 6, 30, 60 or 120 min. After 3 min of pellicle formation, mouthrinses were performed for 3 min with (non-)homogenized UHT- or fresh milk (0.3% or 3.8% fat), 30% UHT-treated cream or different types of casein- or milk protein isolates containing preparations. The specimens were removed after the exposure times and transmission electron microscopy (TEM) was performed. Native pellicle samples served as controls. ResultsTopical ultrastructural pellicle modifications were detected after mouthrinses with all types of homogenized UHT- or fresh milk and after the application of a 3% native casein micelles containing experimental solution. Atypical globular protein structures, identified as casein micelles, were temporarily adsorbed onto the pellicle. They were closely associated with lipid droplets. Furthermore, the mouthrinses occasionally affected the morphology of salivary bacteria. However, no notable ultrastructural alterations remained after 120 min of pellicle formation. ConclusionFor the first time, bovine milk- and micellar casein-induced pellicle modifications were revealed by TEM. The adsorption of micellar casein is possibly due to its molecular interactions. Clinical significanceBovine milk or micellar caseins provide some potential for the development of preventive strategies against bacterial biofilm formation or erosive processes at the tooth surface.

Antibacterial pigment production by Serratia marcescens using different casein types obtained from milk

Prodigiosin, a pigment produced by Serratia marcescensinhibits the growth of different microorganisms and the proliferation of some human cancer cell lines. Prodigiosin is usually produced by fermentations of substrates such as starch and proteins, andpig-ment yield depends on the concentration of the carbon source, stirring speed of cultures, temperature and time of incubation,nitro-gen sources, and pH of medium. In the present study, pigment production was assessed using two types of casein as substrate; pigment yield was greater when casein precipitated with vinegar was used as substrate than when high purity casein was. The maxi-mum prodigiosin production was achieved with 10 g/L casein at pH 8.0. Additionally, supplementation of culture media with glu-cose was found to considerably decrease prodigiosin production and growth inhibition of Staphylococcus aureus, which is directly related to pigment yield. Production in stirred-tank bioreactor at 0.75 vvm aeration was higher than that at 0.5 and 1.0 vvm. Sub-strate type, concentration and pH affected pigment production in Erlenmeyer flasks, whereas aeration rate influenced pigment pro-duction in a stirred-tank bioreactor.

Validation of method for the determination of bovine casein in milk and milk products

Bovine caseins in dairy and dairy products were determined by high performance liquid chromatography (HPLC) with a PDA detector at 280 nm or by sandwich ELISA method. Liquid chromatography method was developed to determine different types of casein including alpha, beta, and kappa casein at high content (% level), which calculate the proportion of casein forms, thus allow the identification of milk sources (cow's milk, goat's milk). The ELISA method determines casein at low content (LOD was of 3mg/kg) which meets the labeling requirements of EU and Japan for food allergens. The validation data show that both methods fit the purpose with the recovery of 78-98% and the coefficient of variation is from 2.4 to 9.5%. The methods have been applied for the determination of casein content in 20 samples of milk, food supplement, cake and candy from Hanois' markets.

Microstructural observation of casein micelles in milk by cryo-electron microscopy of vitreous sections (CEMOVIS).

Casein micelles are present in bovine milk as colloidal particles with diameters of 20-600 nm, which are complex macromolecular assemblies composed of four distinct types of casein and colloidal calcium phosphate (CCP). Multiple structural models of casein micelles have been proposed based on their biochemical or physical properties and observed using electron microscopy. However, the CCP distribution and crosslinking structure between CCP and casein remain unclear. Therefore, the internal structure of casein micelles in raw milk was observed using cryo-electron microscopy of vitreous sections (CEMOVIS) with high precision at high resolution. The results confirmed that the average casein micelle diameter was about 140 nm, and that the CCP diameter in casein micelles was about 2-3 nm, with an average diameter of 2.3 nm. The distribution of CCP in casein micelles was not uniform, with an average interval between CCPs of about 5.4 nm. Areas containing no black particles (attributed to CCP) were present, with an average size of about 19.1 nm. Considering previous reports, these areas possibly correspond to pores or cavities filled with water. Based on differences in the density of structures in casein micelles, we estimated that some of the casein aggregates were able to connect with CCP in a string.

Development and characterization of a novel edible extruded sheet based on different casein sources and influence of the glycerol concentration

Different source of casein depending on their extraction method from milk are available on the market. Sheets from 3 different types of casein (rennet casein, acid casein and sodium caseinate) were developed using a dry process: extrusion. Casein sourcing, plasticizer concentration (13.2% w/w or 24.2% w/w) and relative humidity environment were studied for each sheet through color, density and porosity, water sensitivity and mechanical properties evaluation. A wide range of properties seems to be available through casein based sheets depending on casein source, which affected greatly water solubility (caseinates are 100% water soluble compare to acid and rennet casein). Besides, acid and rennet casein have different behaviour with water and even more with higher glycerol amounts. Indeed, rennet casein sheet is less sensitive to water than acid casein sheet at low glycerol concentration (13.2% w/w) but at the opposite, at high glycerol amount in sheets, rennet casein sheet is more hydrophilic than acid casein sheets.Extrusion is an easy scale up process and it was used to produce casein based sheets with improved water vapor permeability (WVP). These findings can be used to find the suitable food packaging application for each casein based sheet with a low cost and efficient process.

Effect of orthophosphate and calcium on the self assembly of concentrated sodium caseinate solutions

The effect of orthophosphate (0–0.1 m) on the aggregation of sodium caseinate in water (10–80 g L−1) induced by calcium ions was studied using confocal microscopy, sedimentation and 31P magic angle spinning nuclear magnetic resonance spectroscopy. In the presence of calcium ions (0–0.1 m), orthophosphate binds to the caseins leading to the formation of complexes involving all four types of casein. Above a critical molar calcium/protein ratio in the complex, large protein aggregates were formed that sedimented during centrifugation. The critical molar ratio increased from about 6 without added orthophosphate to about 10 in excess orthophosphate. Excess orthophosphate precipitated in the form of calcium phosphate particles and competed with caseins for binding of calcium ions. Binding of calcium ions led to immobilisation of inorganic orthophosphate and organic phophoserines in solid nanoparticles. In excess CaCl2 and orthophosphate, the complexes contained about 13 calcium and 10 orthophosphate ions.

Postprandial Mononuclear NF-κB Activation is Independent of the AGE-content of a Single Meal

Dietary uptake of Advanced Glycation Endproducts (AGE) is supposed to potentially contribute to inflammatory reactions linked to vascular dysfunction and late diabetic complications. One mechanism by which dietary AGE might exert these effects is by activation of the proinflammatory transcription factor NF-kappa-B. The aim of this study was to analyze the postprandial effects of a casein meal with low or high AGE content on postprandial NF-kappaB activation in peripheral blood mononuclear cells (pBMC) of healthy volunteers. Casein was heated for 40 h at 50 degrees C in the presence of sorbitol or glucose, resulting in either minimal (Sorbitol [S]-casein) or large (glucose [G]-casein) amounts of AGE-modified casein. Nine healthy volunteers ate 250 g of both types of casein, whereas both meals were separated at least by 2 weeks. Plasma and pBMC were taken before and 2 h after each meal. Thereafter, the defined AGE carboxymethyllysine (CML) was determined by ELISA and Western blot. NF-kappaB activation in pBMC was assayed using Electrophoretic Mobility Shift Assays (EMSA) and Western blot analysis. S-casein contained only minor amounts of CML and no pentosidine, while G-casein contained large amounts of both. 2 h after ingestion, the S-casein or the G-casein-meal, both, resulted in a non-significant increase in plasma CML and in the intracellular CML-content of pBMC. This was paralleled by a highly significant increase in postprandial mononuclear NF-kappaB-binding activity. Remarkably, neither the extent of NF-kappaB induction (178% for S-casein, 188% for G-casein), nor composition of the NF-kappaB heterodimer (mainly consisting of NF-kappaB p50/p65) were significantly different after intake of S-casein or G-casein. Consistently, Western blots confirmed an increased NF-kappaBp65 nuclear translocation and a decrease of NF-kappaBp65 in the cytoplasm, while no difference in postprandial NF-kappaB nuclear translocation was observed following intake of S-casein or G-casein. Postprandial mononuclear NF-kappaB activation after a single meal is independent of the AGE-content of the ingested protein.

Simulating the self-association of caseins

A 2-D lattice Monte Carlo model is used to simulate the self-association behaviour of block copolymers with a block size and distribution that models the structure of the four types of milk casein. All the model casein molecules form micelles above a certain chain density (the critical micelle concentration, CMC). The different model casein molecules are shown to form micelles with different morphologies at different attractive hydrophobic block interactions, and these morphologies are consistent with the morphologies that have been observed or have been hypothesized for those natural caseins. Model α s1-casein forms linear micelles where the hydrophobic block attraction is weak and flower-like circular micelles with a dense core at stronger attractions. At high chain densities worm-like micelle solutions are formed. α s2-Casein forms small linear micelles at weak attractions, and dense core micelles at high attractions. β-Casein forms dense core, circular and elongated micelles at relatively strong attractions. It too forms a worm-like micellar solution at higher chain densities. At very high chain densities (84%) the conformations may show some evidence of ordered mesophase formation, as has been observed in previous block copolymer simulations.

Selective allergy to sheep’s and goat’s milk proteins

BackgroundCow’s milk proteins are amongst the most common causes of food allergy in infants, and caseins are probably the main allergens. The existence of a high degree of cross-reactivity between milk caseins from different animals has been reported. We describe a 2-year-old boy who experienced allergic reactions after eating and touching sheep’s cheese, but who tolerated cow’s milk and cow’s milk dairy products. He had never ingested milk or milk derivatives from sheep or goat MethodsSkin prick tests were carried out using whey fractions of cow’s milk, whole milk and casein from goat, sheep and cow. We also performed skin prick tests with enzymes used in cheese production. Prick-by-prick tests with cheese made from cow, sheep and goat and their corresponding whole milk were also performed. Total serum IgE and specific IgE to cow’s milk proteins, whole cow’s milk and sheep’s milk were determined. Specific IgE against casein and whole milk from the three different species were determined by ELISA. Inhibition of IgE binding to bovine casein was tested for casein and whole milk from all three species. The proteins of three types of casein and whole milk from cow, sheep and goat were separated by SDS-PAGE and were incubated with the patient’s serum ResultsSkin tests were positive to sheep’s milk and goat and sheep casein and were negative to all cow’s milk proteins and whole cow’s and goat’s milk. Prick-by-prick tests were positive to goat’s and sheep’s cheese and were negative to cow’s cheese. In ELISA-inhibition, sheep’s milk and goat and sheep casein were able to inhibit > 50 % of specific IgE binding to sheep casein. The results of immunoblotting showed that the patient’s circulating IgEs recognized only one band in the lanes corresponding to sheep and goat casein ConclusionsWe report a patient with allergy to sheep’s and goat’s milk proteins but not to cow’s milk proteins. Sheep casein was probably the main allergen causing sensitization in this patient. The results suggest that sheep casein shows a high degree of cross-reactivity with goat casein but not with cow casein. Our patient presented allergic symptoms caused by sheep and goat milk and cheese proteins. However, he was able to tolerate cow’s milk and cow’s milk dairy products without any ill effects

Stability to Oxidation of Spray‐Dried Fish Oil Powder Microencapsulated Using Milk Ingredients

ABSTRACT: Microencapsulation of fish oil was achieved by spray‐drying homogenized emulsions of fish oil using 3 different types of casein as emulsifier and lactose as filler. As the degree of aggregation of the casein emulsifier increased, the vacuole volume of the microencapsulated powders decreased. The shelf life of the powders increased as the degree of aggregation of the casein emulsifier increased at the high homogenization conditions. When micellar casein was used as emulsifier, the shelf life also increased as homogenization conditions increased. Free fat but not surface fat was inversely related to shelf life. Since the type of casein used was confounded with the powder vacuole volume, the increased shelf life may have been due to either factor.

Moisture sorption behaviour of mineral acid, lactic and rennet caseins in the temperature range 27–80 °C

SummaryThe moisture desorption isotherms of mineral acid, lactic and rennet caseins were determined at ˜ 28, 55 and 80 °C. The isotherms were all sigmoid type II according to the BET (Brunauer et al. 1938) classification. A modified Henderson equation was found best to describe the relationship of equilibrium moisture content, water activity (aw) and temperature for all three types of casein. BET monolayer moisture contents and heats of desorption of the three types of casein were calculated. Equilibrium moisture contents at aw 0·432 and 30 °C for mineral acid casein made under a range of manufacturing conditions varied significantly depending on the drying conditions. More severe drying conditions produced lower equilibrium moisture contents.

Increases of serum phosphorus concentration and duodenal, renal and femur alkaline phosphatase (EC 3.1.3.1) activities of normal rats fed 2000 ppm aluminum diets

In order to investigate the dietary effect of calcium on aluminum-induced hypophosphatemia, five types of diet, sucrose, lactose, milk, casein and soy protein, were prepared. These diets differed with regard to Ca concentration, and carbohydrate or protein sources which were expected to modify intestinal Ca absorption. Weanling Wistar rats were fed these diets for 67 days with the addition of Al at a concentration of 2000 ppm. Nutritional constituents had little effect on Al accumulation in the duodenum and bone. Al treatments had no effects on increases of body weight. The Al treatments significantly increased duodenum alkaline phosphatase (ALPase) activity and serum phosphorus concentration in all of the dietary groups. Slight but significant decreases of bone weight were observed. There were no significant increases in serum Al concentration but bone and kidney ALPase activities were also observed. These results suggest that Al ingestion can cause hyperphosphatemia in the intact animal. Effects of Al on nutrition should be considered even if serum Al concentration does not increase.

The Use of Marginal Likelihood for a Diagnostic Test for the Goodness of Fit of the Simple Linear Regression Model

A novel test procedure is proposed to diagnose the goodness of fit of a simple regression model by applying a marginal likelihood under the assumption of smoothness of the alternative regression curve. No specific form for the alternative regression function is assumed. An advantage of the proposed test procedure is that it simultaneously provides an estimated regression curve (spline). Some existing diagnostic procedures are explored in relation to the one proposed. The procedure is applied to data of a spectrophotometric analysis of mixtures of two types of flour, cornstarch and casein (soybean).

The Use of Marginal Likelihood for a Diagnostic Test for the Goodness of Fit of the Simple Linear Regression Model

A novel test procedure is proposed to diagnose the goodness of fit of a simple regression model by applying a marginal likelihood under the assumption of smoothness of the alternative regression curve. No specific form for the alternative regression function is assumed. An advantage of the proposed test procedure is that it simultaneously provides an estimated regression curve (spline). Some existing diagnostic procedures are explored in relation to the one proposed. The procedure is applied to data of a spectrophotometric analysis of mixtures of two types of flour, cornstarch and casein (soybean).

Comparison of Methods for the Isolation of Salmonella Species from Lactic Casein

ABSTRACTThe efficiency of eight pre‐enrichment media (lactose broth, two modifications of lactose broth (added NaHCO3 or added NaHCO3 and brilliant green dye), lauryl tryptose broth, nutrient broth, buffered peptone water, trypticase soy broth, and chemically defined M‐9 medium) for recovering three Salmonella serotypes from casein was determined. Lowest Salmonella most probable numbers (MPNs) in artificially inoculated casein were found when samples were pre‐enriched in either modification of lactose broth. None of the other media consistently gave the highest Salmonella MPNs. When 35 and 43°C incubation temperatures were compared during the pre‐enrichment and selective enrichment stages of the isolation procedures, highest MPN values were obtained when 35°C was used throughout the analytical procedure. Blended casein homogenates required adjustment to pH 6.8 ± 0.2 for optimal recovery of Salmonella. Lactose broth used under these conditions of incubation temperature and pH adjustment generally resulted in methods sensitive enough to recover one Salmonella cell per gram of four types of casein (lactic, rennet, acid, and sodium caseinate).

Nitrogen Mobilization and Proteolytic Activities in Germinating and Maturing Bush Beans (Phaseolus vulgarisPhaseolus vulgaris L.)

Summary Changes in the nitrogen contents and in the extractable activities of amino-, carboxy- and endopeptidases were analyzed in bush beans (Phaseolus vulgaris L.) throughout the life cycle. Two types of casein digesting enzymes (endopeptidases) were found. One type was the main activity extracted from cotyledons during germination with a pH optimum around pH 5.5 and was stimulated by the presence of mercaptoethanol in the incubation medium. The other type showed high activities in leaf extracts, was most active around pH 7 and was slightly inhibited by the presence of 0.1 % mercaptoethanol in the incubation medium. Beside the main acidic caseolytic activity, the neutral type was also present in cotyledons during germination. In detached cotyledons the acidic activity increased more gradually than in controls, but the neutral type reached higher activities. Aminopeptidase activity decreased during germination. In detached cotyledons this decrease was delayed. Carboxypeptidase activity increased during germination and was not affected by removing the axis. No major differences in nitrogen mobilization or in the pattern of proteolytic enzymes were observed between illuminated and etiolated seedlings. In leaves no major changes in the relative activities of exo- and endopeptidases were detected during the life cycle. In senescing leaves and pods aminopeptidase activity decreased while carboxypeptidase and neutral endopeptidase activities remained stable or increased slightly. The large increase in the neutral endopeptidase activity observed in leaves of maturing cereals could not be found in bean leaves. Also the sharp decrease of exo- peptidase activities found in senescing leaves of wheat and corn did not occur in bean leaves. Since there are major differences between the nitrogen metabolism of cereals and legumes, a different regulation of nitrogen mobilization and of the proteolytic activities appears reasonable.

Influence of dehydration method on the adsorption of benzene vapor by dried casein

Washed casein micelles were dehydrated by serial transfer through solvents of decreasing polarity followed by drying in vacuo. The product adsorbed approximately three times as much benzene as lyophilized casein for all P P 0 values at 24 and 30°C. Adsorbed C 5H 6 molecules are very mobile on the surfaces of the lyophilized particles, − q st = 8.7 kcal/mole over the entire isotherm. However, much of the benzene is in a more tightly bound adsorbed state on solvent transfer dehydrated casein, with − q st gradually decreasing from a high of 20 kcal/mole to a constant value near 8 kcal/mole. Both types of casein adsorbed more C 6H 6 than anticipated from BET surface areas calculated from low temperature N 2 adsorption data. The results suggest that the apolar amino acid residues of the casein subunits, which are normally squeezed into cavities in water according to theories of hydrophobic bonding, may be separated when water is replaced with a less polar solvent. Ultimately a porous dried product is thus obtained with localized binding sites for benzene, rather than hydrophobic regions in the macromolecule.