scholarly journals Optical backscatter method for determining thermal denaturation of β-lactoglobulin and other whey proteins in milk

2013 ◽  
Vol 96 (3) ◽  
pp. 1356-1365 ◽  
Author(s):  
Alisa Lamb ◽  
Fred Payne ◽  
Youling L. Xiong ◽  
Manuel Castillo
Keyword(s):  
Thermal Denaturation ◽  
Whey Proteins ◽  
Β Lactoglobulin

scholarly journals A calorimetric study of the thermal denaturation of whey proteins in simulated milk ultrafiltrate

1977 ◽  
Vol 44 (3) ◽  
pp. 509-520 ◽  
Author(s):  
M. Rüegg ◽  
Ursula Moor ◽  
B. Blanc
Keyword(s):  
Heat Treatment ◽  
Xanthine Oxidase ◽  
Conformational Changes ◽  
Thermal Denaturation ◽  
Whey Proteins ◽  
Calorimetric Study ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Β Lactoglobulin ◽  
Dsc Thermograms

SummaryDifferential scanning calorimetry (DSC) was used to study thermal transitions of the following whey proteins and enzymes in milk ultrafiltrate solution: β-lactoglobulin, α-lactalbumin, serum albumin, γ-globulin, apo- and Fe-lactoferrin, lysozyme, ribonuclease, α-chymotrypsin and xanthine oxidase. Denaturation enthalpies (ΔHD), denaturation temperatures (TD) and the half width of the denaturation peaks in DSC thermograms (ΔT½D) were determined and the degree of renaturation was estimated by rescanning previously denatured samples. A fair correlation between the results obtained by DSC and other more classical methods was found in general. However, for some proteins (α-lactalbumin, lysozyme, ribonuclease and xanthine oxidase), which have so far been considered relatively thermostable, calorimetry reveals conformational changes starting at temperatures as low as about 45 °C. In these cases thermostability observed after heat treatment of milk should be interpreted in terms of renaturation and not of high temperatures of denaturation.

scholarly journals Low resolution NMR spectroscopy: a tool to study protein denaturation: I. Application to diamagnetic whey proteins

1989 ◽  
Vol 56 (2) ◽  
pp. 211-222 ◽  
Author(s):  
Pierre Lambelet ◽  
Rafael Berrocal ◽  
Francine Ducret
Keyword(s):  
Nmr Spectroscopy ◽  
Whey Protein ◽  
Thermal Denaturation ◽  
Protein Denaturation ◽  
Whey Proteins ◽  
Whey Protein Concentrate ◽  
Water Proton ◽  
Low Resolution ◽  
Β Lactoglobulin

SummaryA method using low resolution NMR spectroscopy is described for investigating whey protein thermal denaturation. The method is based on measuring at 20 °C changes in water proton transverse (T2) relaxation parameter following the denaturing treatment. This parameter is shown to be sensitive to protein denaturation and not to other phenomena such as gelation. Examples are given for the qualitative study of protein thermal denaturation in whey protein concentratc, β-lactoglobulin, α-lactalbumin, bovine serum albumin and immunoglobulins aqueous solutions and for the quantitative determination of thermal denaturation in whey protein concentrate solutions.

Thermal denaturation of bovine β-lactoglobulin in different protein mixtures in relation to antigenicity

2019 ◽  
Vol 91 ◽  
pp. 89-97 ◽  
Author(s):  
Dimuthu Bogahawaththa ◽  
Jayani Chandrapala ◽  
Todor Vasiljevic
Keyword(s):  
Thermal Denaturation ◽  
Β Lactoglobulin

The dynamics of individual whey protein concentrations in cows’ mammary secretions during the colostral and early lactation periods

2018 ◽  
Vol 86 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Raquel F.S. Raimondo ◽  
Juliana S.P. Ferrão ◽  
Samantha I. Miyashiro ◽  
Priscila T. Ferreira ◽  
João Paulo E. Saut ◽  
...  
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Whey Proteins ◽  
Total Proteins ◽  
Mature Milk ◽  
Rennet Coagulation ◽  
Sds Page ◽  
Different Types ◽  
Biuret Method ◽  
Jersey Cows ◽  
Β Lactoglobulin

AbstractThe bovine whey consists of more than 200 different types of proteins, of which β-lactoglobulin, α-lactalbumin, serum albumin, immunoglobulins and lactoferrin predominate. However, their concentrations are not stable due to the existence of protein dynamics during a transition from colostrum secretion to mature milk. To evaluate the dynamics of whey proteins of Jersey cows during a colostral phase and first month of lactation and an influence of the number of lactations, 268 milk samples from 135 Jersey cows were selected through a clinical evaluation. Whey was obtained by rennet coagulation of the mammary secretion. The concentration of total proteins was determined by the biuret method and their fractions were identified by 12% dodecyl sulfate-polyacrylamide gel electrophoresis (12% SDS-PAGE). Maximum concentrations of all protein fractions were observed in the first 12 h of lactation, reducing over the course of the study. Modification of the protein predominance was also observed. The transition from colostrum secretion to milk occurred between 24 and 72 h postpartum. There was an influence of the number of lactations on the dynamics of whey proteins, indicating that multiparous cows had better immunological and nutritional quality when compared to primiparous cows.

Assessment of the Thermal Treatment of Milk during Continuous Microwave and Conventional Heating

1996 ◽  
Vol 59 (8) ◽  
pp. 889-892 ◽  
Author(s):  
ROSINA LOPEZ-FANDIÑO ◽  
MAR VILLAMIEL ◽  
NIEVES CORZO ◽  
AGUSTIN OLANO
Keyword(s):  
Heat Treatment ◽  
Continuous Flow ◽  
Thermal Denaturation ◽  
Microwave Treatment ◽  
Conventional Heating ◽  
Treatment Intensity ◽  
Heat Distribution ◽  
Conventional System ◽  
Effective System ◽  
Β Lactoglobulin

The effect of continuous-flow microwave treatment of milk was estimated by using indicators of the heat treatment intensity (β-lactoglobulin denaturation, inactivation of alkaline phosphatase and lactoperoxidase). Results were compared with those obtained using a conventional process having the same heating, holding, and cooling phases. Continuous microwave treatment proved to be an effective system for pasteurizing milk, with the inclusion of a holding phase to maintain the time and temperature conditions required. At high pasteurization temperatures, the extent of thermal denaturation observed with the microwave treatment was lower than that obtained with the conventional system. This result could be attributed to a better heat distribution and the lack of hot surfaces contacting the milk in the case of the microwave unit.

Peculiarities of extraction of β-lactoglobuline in protein mineral concentrates at electroactivation of whey

2020 ◽  
Vol 2 (1) ◽  
pp. 52-68
Author(s):  
Mircea BOLOGA ◽  
Elvira VRABIE ◽  
Irina PALADII ◽  
Olga ILIASENCO ◽  
Tatiana STEPURINA ◽  
...  
Keyword(s):  
Protein Content ◽  
Whey Proteins ◽  
Sodium Dodecyl ◽  
Total Protein Content ◽  
Treatment Regimens ◽  
Sds Page ◽  
Different Types ◽  
Lower Protein ◽  
Β Lactoglobulin ◽  
Excellent Source

Introduction. Whey is a by-product and an excellent source of proteins that is rather aggressive due to a large amount of organic substances it contains. The electro-activation of whey applied in the experiments is a wasteless method that allows the va-lorification of all whey components. β-lactoglobulin (β-Lg) makes up 50% of the whey proteins and 12% of the total protein content in milk. Material and methods. The recovery of β-Lg in protein-mineral concentrates (PMC) by electro-activation processing of different types of whey with different initial protein content was investigated in seven configurations. The recovery of protein fractions in the PMCs were analyzed via electrophoresis with sodium dodecyl sulfate (SDS-PAGE) and 15% non-denaturing polyacrylamide gel (PAAG).      Results. Whey electro-fractionation and the obtaining of PMCs with predetermined protein content, namely of β-Lg, were studied on three whey types, processed at different treatment regimens and in seven configurations. The proper management of electroactivation by varying the treatment regimens will allow the electro-fractionation of different types of dairy by-products. Conclusions. The maximum amount of β-Lg recovered in PMCs on electroactivation is  66-71% depending on the processed whey and on the treatment regimens. Obviously, the extraction of β-Lg from initially lower protein content shows a higher recovery degree of β-Lg. The registered temperatures allows formation of PMCs without thermal denaturation.

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