Evaluation of a sulphydryl–disulphide exchange index (SEI) for whey proteins—β-lactoglobulin and bovine serum albumin

2003 ◽  
Vol 83 (4) ◽  
pp. 541-545 ◽  
Author(s):  
R Owusu-Apenten
2017 ◽  
Vol 13 (1) ◽  
pp. 33-45
Author(s):  
Aneta Brodziak ◽  
Jolanta Król ◽  
Anna Litwińczuk ◽  
Anna Wolanciuk

The aim of the study was to determine the correlations between the concentrations of major whey proteins in cow milk. A total of 2,278 milk samples from Polish Holstein-Friesian (Black-and-White and Red-and-White varieties), Simmental and Jersey cows were analysed. In each sample the content of major whey proteins, i.e. α-lactalbumin, β-lactoglobulin, bovine serum albumin, lactoferrin and lysozyme were determined by the RP-HPLC method. Matrix scatter plots were prepared to determine the correlations between the concentrations of individual whey proteins. In the vast majority of cases a significant relationship was found between the content of individual whey proteins. Taking into account the production season and breed of cow, highly significant (p=0.001) negative correlation coefficients were obtained for the content of α-lactalbumin and bovine serum albumin, for α-lactalbumin and lysozyme, for β-lactoglobulin and bovine serum albumin, and for β-lactoglobulin and lysozyme. Positive correlations were observed for the concentrations of α-lactalbumin with β-lactoglobulin, lactoferrin and lysozyme, as well as for bovine serum albumin with lysozyme.


2014 ◽  
Vol 77 (3) ◽  
pp. 427-434 ◽  
Author(s):  
GILLES ROBITAILLE ◽  
SÉBASTIEN CHOINIÈRE ◽  
TIMOTHY ELLS ◽  
LOUISE DESCHÈNES ◽  
AKIER ASSANTA MAFU

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.


1966 ◽  
Vol 21 (4) ◽  
pp. 305-313 ◽  
Author(s):  
G. Reske ◽  
F. Nimmerfall ◽  
J. Stauff

Interactions of eosin with three different substrates, β-lactoglobuline, bovine serum albumin and cysteine, in aqueous solutions of pH 7 under illumination with light of wavelengths 5200—5400 Å are investigated by changes in absorption spectrum characteristics, SH-group activities and phosphorescence intensities.Only with bovine serum albumin the major part of protein conversion, as shown by spectral changes and diminution of SH-groups due to eosin-sensitized photo-oxidation. In β-lactoglobuline an oxidizing photoreaction occurs, by which eosin is vanishing to the same degree as the protein shows loss of SH-groups and spectral alterations indicating attack on aromatic amino acid residues. There is no red shift of the eosin absorption band at 5170 Å as is observed in solutions of bovine serum albumin, where the intensity of phosphorscence is about 100 fold compared with the intensity obtained by solutions of β-lactoglobulin.The aerobic eosin photoreaction in solutions of β-lactoglobulin is faster than aerobic photobleaching of the dye. Still faster is its bleaching photoreaction with cysteine, which is nearly independent of oxygen.


1991 ◽  
Vol 40 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Naotoshi Matsudomi ◽  
Douglas Rector ◽  
J.E. Kinsella

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