Heat-Induced Redistribution of Disulfide Bonds in Milk Proteins. 1. Bovine β-Lactoglobulin

2004 ◽  
Vol 52 (25) ◽  
pp. 7660-7668 ◽  
Author(s):  
Lawrence K. Creamer ◽  
Annie Bienvenue ◽  
Hanna Nilsson ◽  
Marie Paulsson ◽  
Miriam van Wanroij ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Milk Proteins ◽  
Β Lactoglobulin

Heat-Induced Redistribution of Disulfide Bonds in Milk Proteins. 2. Disulfide Bonding Patterns between Bovine β-Lactoglobulin and κ-Casein

2004 ◽  
Vol 52 (25) ◽  
pp. 7669-7680 ◽  
Author(s):  
Edwin K. Lowe ◽  
Skelte G. Anema ◽  
Annie Bienvenue ◽  
Michael J. Boland ◽  
Lawrence K. Creamer ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Milk Proteins ◽  
Disulfide Bonding ◽  
Β Lactoglobulin ◽  
Bonding Patterns

Occurrence of milk proteins in the urine of cows during an extended milking interval

1967 ◽  
Vol 34 (1) ◽  
pp. 27-30 ◽  
Author(s):  
R. L. J. Lyster ◽  
J. V. Wheelock
Keyword(s):  
Molecular Weight ◽  
Milk Proteins ◽  
Immunological Methods ◽  
Factors Affecting ◽  
Β Lactoglobulin

SummaryImmunological methods have been used to test samples of urine from 5 cows for the presence of milk proteins. None could be detected when the cows were milked twice daily at the usual intervals, but during an extended milking interval α-lactalbumin was found in the urine of all 5 cows and β-lactoglobulin in the urine of 2 cows. The urine of one cow during and after a milking interval of 39 h contained 1·63 g α-lactalbumin, 1·12 g β-lactoglobulin and a small amount of casein. One of the factors affecting the transfer of these milk constituents from the udder to the urine appears to be their molecular weight.

Attachment of Listeria innocua to Polystyrene: Effects of Ionic Strength and Conditioning Films from Culture Media and Milk Proteins

2014 ◽  
Vol 77 (3) ◽  
pp. 427-434 ◽  
Author(s):  
GILLES ROBITAILLE ◽  
SÉBASTIEN CHOINIÈRE ◽  
TIMOTHY ELLS ◽  
LOUISE DESCHÈNES ◽  
AKIER ASSANTA MAFU
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bacterial Adhesion ◽  
Bovine Serum ◽  
Biofilm Formation ◽  
Milk Protein ◽  
Milk Proteins ◽  
Listeria Innocua ◽  
Conditioning Films ◽  
Β Lactoglobulin

It is recognized that bacterial adhesion usually occurs on conditioning films made of organic macromolecules absorbed to abiotic surfaces. The objectives of this study were to determine the extent to which milk protein–coated polystyrene (PS) pegs interfere with biofilm formation and the synergistic effect of this conditioning and hypertonic growth media on the bacterial adhesion and biofilm formation of Listeria innocua, used as a nonpathogenic surrogate for Listeria monocytogenes. PS pegs were uncoated (bare PS) or individually coated with whey proteins isolate (WPI), β-lactoglobulin, bovine serum albumin, or tryptic soy broth (TSB) and were incubated in bacterial suspensions in modified Welshimer's broth. After 4 h, the number of adherent cells was dependent on the coating, as follows: TSB (107 CFU/ml) > bare PS > β-lactoglobulin > bovine serum albumin ≈ WPI (104 CFU/ml). The sessile cell counts increased up to 24 h, reaching >107 CFU per peg for all surfaces (P > 0.1), except for WPI-coated PS; this indicates that the inhibitory effects of milk protein conditioning films are transient, slowing down the adhesion process. The 4-h bacterial adhesion on milk protein–coated PS in modified Welshimer's broth supplemented with salt (0 to 10% [wt/vol]) did not vary (P > 0.1), indicating that conditioning with milk proteins was the major determinant for inhibition of bacterial adhesion and that the synergetic effect of salt and milk proteins on adhesion was minimal. Moreover, the presence of 5 to 10% salt significantly inhibited 24-h biofilm formation on the TSB-coated and bare PS, with a decrease of >3 log at 10% (wt/vol) NaCl and almost completely depleted viable sessile bacteria on the milk protein–coated PS.

scholarly journals Development and Validation of a Method for the Quantification of Milk Proteins in Food Products Based on Liquid Chromatography with Mass Spectrometric Detection

2011 ◽  
Vol 94 (4) ◽  
pp. 1043-1059 ◽  
Author(s):  
Petra Lutter ◽  
Véronique Parisod ◽  
Hans Weymuth
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Internal Standard ◽  
Milk Proteins ◽  
Skim Milk Powder ◽  
Selected Reaction Monitoring ◽  
Validation Data ◽  
Development And Validation ◽  
Protein Rich ◽  
Β Lactoglobulin

Abstract The protection of allergic consumers is crucial to the food industry. Therefore, accurate methods for the detection of food allergens are required. Targeted detection of selected molecules by MS combines high selectivity with accurate quantifcation. A confrmatory method based on LC/selected reaction monitoring (SRM)-MS/MS was established and validated for the quantifcation of milk traces in food. Tryptic peptides of the major milk proteins β-lactoglobulin, β-casein, αS2-casein, and κ-casein were selected as quantitative markers. Precise quantifcation was achieved using internal standard peptides containing isotopically labeled amino acids. For each peptide, qualifer and quantifer fragments were selected according to Commission Decision 2002/657/EC. A simple sample preparation method was established without immunoaffnity or SPE enrichment steps for food matrixes containing different amounts of protein, such as baby food, breakfast cereals, infant formula, and cereals. Intermediate reproducibility, repeatability, accuracy, and measurement uncertainty were determined for each matrix. LOD values of 0.2–0.5 mg/kg, e.g., for β-lactoglobulin, were comparable to those obtained with ELISA kits. An LOQ of approximately 5 mg/kg, expressed as mass fraction skim milk powder, was validated in protein-rich infant cereals. The obtained validation data show that the described LC/SRM-MS/MS approach can serve as a confrmatory method for the determination of milk traces in selected food matrixes.

Comparison of heat and pressure treatments of skim milk, fortified with whey protein concentrate, for set yogurt preparation: effects on milk proteins and gel structure

2000 ◽  
Vol 67 (3) ◽  
pp. 329-348 ◽  
Author(s):  
ERIC C. NEEDS ◽  
MARTA CAPELLAS ◽  
A. PATRICIA BLAND ◽  
PRETIMA MANOJ ◽  
DOUGLAS MACDOUGAL ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Whey Protein ◽  
Skim Milk ◽  
Milk Proteins ◽  
Whey Protein Concentrate ◽  
Protein Concentrate ◽  
Casein Micelles ◽  
Micelle Structure ◽  
Dynamic Structures ◽  
Β Lactoglobulin

Heat (85 °C for 20 min) and pressure (600 MPa for 15 min) treatments were applied to skim milk fortified by addition of whey protein concentrate. Both treatments caused > 90% denaturation of β-lactoglobulin. During heat treatment this denaturation took place in the presence of intact casein micelles; during pressure treatment it occurred while the micelles were in a highly dissociated state. As a result micelle structure and the distribution of β-lactoglobulin were different in the two milks. Electron microscopy and immunolabelling techniques were used to examine the milks after processing and during their transition to yogurt gels. The disruption of micelles by high pressure caused a significant change in the appearance of the milk which was quantified by measurement of the colour values L*, a* and b*. Heat treatment also affected these characteristics. Casein micelles are dynamic structures, influenced by changes to their environment. This was clearly demonstrated by the transition from the clusters of small irregularly shaped micelle fragments present in cold pressure-treated milk to round, separate and compact micelles formed on warming the milk to 43 °C. The effect of this transition was observed as significant changes in the colour indicators. During yogurt gel formation, further changes in micelle structure, occurring in both pressure and heat-treated samples, resulted in a convergence of colour values. However, the microstructure of the gels and their rheological properties were very different. Pressure-treated milk yogurt had a much higher storage modulus but yielded more readily to large deformation than the heated milk yogurt. These changes in micelle structure during processing and yogurt preparation are discussed in terms of a recently published micelle model.

Allergy

PEDIATRICS ◽  
1991 ◽  
Vol 87 (6) ◽  
pp. 985-992
Keyword(s):  
Solid Phase ◽  
Milk Proteins ◽  
Subsequent Development ◽  
Specific Ige ◽  
Cow’S Milk Allergy ◽  
Cow’S Milk ◽  
Milk Allergy ◽  
Cow's Milk ◽  
Cow's Milk Allergy ◽  
Β Lactoglobulin

Pathophysiology MATERNAL IMMUNE STATUS AGAINST β-LACTOGLOBULIN AND COW'S MILK ALLERGY IN THE INFANT Casmir GJA, Duchateau J, Cuvelier P, Vis HL. Ann Allergy. 1989;63:517-519 Purpose of the Study The reported frequency of cow's milk allergy in children varies between 0.3% and 7.5% (population with earlier weaning has higher incidence). A thorough family history of atopy and cord IgE level at birth have been used to predict infants "at risk." Previous studies have shown that high cord IgE level (exceeding 1 IU/mL) was predictive of subsequent development of atopic disease. The purpose of this study was to follow-up the predictive relationship of maternal IgG-anti-BLG (IgG against β-lactoglobulin which is a major cow's milk antigen) and allergic manifestations in the infant. Study Population: Subject Section Mothers. All women were selected from the obstetric department of St Pierre Hospital in Brussels, Belgium. Infants. 69 infants were chosen who were born to these mothers by vaginal delivery and were fed cow's milk. Methods Clinical Evaluation. Every month during the first 6 months of life, infants were examined clinically for allergic symptoms. Gastrointestinal signs (diarrhea, vomiting, colic), atopic dermatitis, and respiratory problems (asthma, chronic cough, rhinitis) were recorded. Symptomatic children were treated with Alfare (Nestle) containing hydrolysates of cow's milk proteins with minimal allergenicity. Biologic Investigations. IgG-anti-BLG levels in mothers' sera were measured using solid-phase radioimmunoassay method. These levels were expressed in arbitrary units per milliliter. All children were screened for total IgE levels at 5 days of age. Specific IgE anti-cow's milk radioallergosorbent tests (RASTs) were performed in all patients at 1 month of age.

scholarly journals MAJOR GOAT MILK PROTEIN: SEPARATION AND CHARACTERIZATION BY “LAB-ON-A-CHIP” MICROFLUIDIC ELECTROPHORES

2018 ◽  
Vol 35 (2) ◽  
Author(s):  
ALESSA SIQUEIRA DE O. DOS SANTOS ◽  
VANEIDA MARIA MEURER ◽  
FABIANO FREIRE COSTA ◽  
IGOR MOURA DE PAIVA ◽  
GISELE NOGUEIRA FOGAÇA ◽  
...  
Keyword(s):  
Protein Separation ◽  
Whey Proteins ◽  
Milk Proteins ◽  
Goat Milk ◽  
Lab On A Chip ◽  
Cow Milk ◽  
Total Percentage ◽  
Chip Technology ◽  
Sds Page ◽  
Β Lactoglobulin

This work presents the electrophoretic profile of goat and cow milk samples and their mixtures using microfluidic and conventional electrophoresis. The microfluidic method allowed the separation of the major caseins from milk, excepting the goat κ-casein.  Besides, the major whey proteins were separated with perfect distinction of A and B β-lactoglobulin variants. Comparing to SDS-PAGE, a variation in the molecular weight was observed in all milk proteins. However, A and B β-lactoglobulin variants could not be isolated using SDS-PAGE. Although urea-PAGE did not show high resolution among whey proteins, γ-, κ-, β-, and α-caseins were clearly identified. This method also showed a lower limit detection of cow milk in mixture samples than the "lab-on-a-chip" electrophoresis. In both methods, the highest linearity obtained from plotting total percentage against cow milk concentration was observed by using cow αs1-casein (R2 = 0.986 and R² = 0.973). This result indicates that microfluidic electrophoresis is an effective tool to detect the presence of some proteins in goat and cow milk, and in mixtures. Microfluidic chip technology might will complement the current methods for analyzing milk proteins, highlighting its speed amount of reagents and whey protein separation, which showed a better result than urea or SDS-PAGE

MILK ALLERGY1

1973 ◽  
Vol 36 (4) ◽  
pp. 225-231 ◽  
Author(s):  
Joseph R. Spies
Keyword(s):  
Dairy Products ◽  
Lactose Intolerance ◽  
Milk Proteins ◽  
Basic Research ◽  
Milk Allergy ◽  
Etiological Agents ◽  
Β Lactoglobulin ◽  
Hydrolysis Of ◽  
In Infants And Children

A general review of milk allergy and a summary of current research on milk at Dairy Products Laboratory (DPL) is presented. Milk allergy occurs primarily in infants and children under 2 years of age. It became more prevalent in the U.S. as breast feeding declined and feeding of cow's milk increased. Milk allergy (atopic and anaphylactic) has an immunological basis as distinguished from such diseases as lactose intolerance and galactosemia. The reported incidence of milk allergy varies widely from 30% in allergic children to 0.1 to 7% in nonallergic children. Symptoms of milk allergy are asthma, rhinitis, vomiting, abdominal pain, diarrhea, urticaria, and anaphylaxis. Crib deaths have been attributed to milk allergy. Prognosis is that milk allergy usually disappears by age 2. Milk proteins are the etiological agents in milk allergy. Milk contains from 12–14 immunologically distinguishable proteins, all of which are potential allergens. DPL is doing basic research on milk allergens to elucidate the mechanism of the allergic response to ingested milk. Demonstration of new antigens (potential allergens) generated by brief pepsin hydrolysis of four milk proteins-casein, α-lactalbumin, β-lactoglobulin and bovine serum albumin, is the basis for a new concept of the role of digestion products in immediate type milk and food allergy.

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