scholarly journals Investigation of Age Gelation in UHT Milk

Beverages ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 95 ◽  
Author(s):  
Jared Raynes ◽  
Delphine Vincent ◽  
Jody Zawadzki ◽  
Keith Savin ◽  
Dominik Mertens ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Storage Time ◽  
Milk Protein ◽  
Degradation Products ◽  
Skim Milk ◽  
Protein Variant ◽  
Uht Milk ◽  
Milk Samples ◽  
Native Proteins ◽  
Β Lactoglobulin

Milk samples with twelve combinations of κ- and β-casein (CN) and β-lactoglobulin (β-Lg) variants were obtained to investigate the effect of protein variant on the mechanism/s of age gelation in ultra-high temperature (UHT) skim milk. Only milk groups with κ-CN/β-CN/β-Lg combinations AB/A1A2/AB and AB/A2A2/AB suffered from the expected age gelation over nine months storage, although this could not be attributed to the milk protein genetic variants. Top-down proteomics revealed three general trends across the twelve milk groups: (1) the abundance of intact native proteins decreases over storage time; (2) lactosylated proteoforms appear immediately post-UHT treatment; and (3) protein degradation products accumulate over storage time. Of the 151 identified degradation products, 106 (70.2%) arose from β-CN, 33 (21.9%) from αs1-CN, 4 (2.7%) from β-Lg, 4 (2.7%) from α-La, 3 (2%) from κ-CN and 1 (0.7%) from αs2-CN. There was a positive correlation between milk viscosity and 47 short peptides and four intact proteoforms, while 20 longer polypeptides and 21 intact proteoforms were negatively correlated. Age gelation was associated with specific patterns of proteolytic degradation and also with the absence of the families Bacillaceae, Aerococcaceae, Planococcaceae, Staphylococcaceae and Enterobacteriaceae, present in all the non-gelling milk groups pre-UHT.

Influence of κ-casein and β-lactoglobulin genetic variants on the heat stability of milk

1995 ◽  
Vol 62 (4) ◽  
pp. 593-600 ◽  
Author(s):  
Gilles Robitaille
Keyword(s):  
Genetic Variants ◽  
Skim Milk ◽  
Heat Stability ◽  
Type B ◽  
Maximum Heat ◽  
Mean Values ◽  
Milk Samples ◽  
Reconstituted Milk ◽  
Β Lactoglobulin ◽  
Minimum Heat

SUMMARYHeat coagulation time-pH curves at 140°C were obtained for 43 blended skim milk samples from Holstein cows to determine the effects of genetic variants of κ-casein and β-lactoglobulin on milk heat stability. The blended milk samples were similar in terms of protein content and milk salts, but were genotypically different for κ-casein (AA, AB) and β-lactoglobulin (AA, AB, BB). Type A curves were obtained for all milks. Maximum heat stability was affected by the κ-casein genotype (AB > AA, P < 0·01) but the influence of the β-lactoglobulin genotype was only significant when the κ-casein AA genotype was present (β-lactoglobulin AA > BB, P < 0·0001). Minimum heat stability was significantly higher (P < 0·0001) for milk genotyped κ-casein AB:β-lactoglobulin BB. The effects of milk genotyped κ-casein BB on maximum and minimum heat stability were determined by analysing individual milks: κ-casein BB:β-lactoglobulin AB (n=8) and reconstituted milks: κ-casein BB:β-lactoglobulin AA, AB and BB (n = 17). Type B curves were obtained on three occasions for individual κ-casein BB:β-lactoglobulin AB milk and on five occasions in the case of reconstituted milks with κ-casein BB:β-lactoglobulin AA, AB and BB. This suggests a relationship between the type B curve and the κ-casein B genetic variant. Comparison of the mean values of heat stability at the pH of maximum heat stability of each individual and reconstituted milk genotype suggested that the best genotype for κ-casein in terms of heat stability was BB.

Effects of milk protein genetic variants and composition on heat stability of milk

1987 ◽  
Vol 54 (2) ◽  
pp. 219-235 ◽  
Author(s):  
Douglas M. McLean ◽  
E. R. Bruce Graham ◽  
Raul W. Ponzoni ◽  
Hugh A. Mckenzie
Keyword(s):  
Genetic Variants ◽  
Skim Milk ◽  
Heat Stability ◽  
Coagulation Time ◽  
Maximum Heat ◽  
Milk Samples ◽  
Stage Of Lactation ◽  
Ph Curve ◽  
Jersey Cows ◽  
Β Lactoglobulin

SummarySkim milk samples from 126 Friesian and 147 Jersey cows in eight commercial herds were preheated at 85 °C for 30 min and concentrated to 200 g l−1 total solids. A heat coagulation time–pH curve was determined at 120 °C for each treated sample. Heat coagulation times ranged from 1 to 50 min at the non-adjusted pH and 1 to 60 min at the pH of maximum stability. The following statistically significant effects were found. Maximum heat stability was affected by genetic variants of κ-casein (B > AB > A; P < 0·001) and β-lactoglobulin (B, AB>A; P < 0·05) whereas natural heat stability was affected only by κ-casein genetic variants (B > AB > A; P < 0·001). Maximum and natural heat stability were corre-lated positively with β-casein and κ-casein concentrations and were negatively correlated with αs1-casein and β-lactoglobulin concentrations. Milk from Jersey cows had greater maximum and natural heat stability than milk from Friesian cows. Differences were found between herds within breed for natural heat stability, but not for maximum heat stability. Maximum heat stability declined with age of the cow. The heat stability of skim milk samples taken from 40 Jersey cows in one of the herds was determined at 140 °C. A considerable variation was found in the coagulation time–pH curves. There was a difference in natural heat stability between κ-casein variants (B > AB; P < 0°05). Natural and maximum heat stability were correlated positively with urea concentration. No relationship was found between the heat stability of preheated concentrated skim milk and the heat stability of the original skim milk. The pH of skim milk samples was associated with αs1-casein genetic variant, age of cow, stage of lactation and concentration of γ-casein.

Milk protein polymorphism in Danish dairy cattle and the influence of genetic variants on milk yield

1990 ◽  
Vol 57 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Anne-Marie Bech ◽  
K. Rotvig Kristiansen
Keyword(s):  
Dairy Cattle ◽  
Milk Fat ◽  
Milk Protein ◽  
Gene Frequencies ◽  
Black And White ◽  
Milk Samples ◽  
Yield Parameters ◽  
Jersey Cows ◽  
Β Lactoglobulin ◽  
Danish Dairy

SummaryIn milk samples from 549 cows of the breeds Danish Jersey, Red Danish Dairy Cattle (RDM), and Black and White Danish Dairy Cattle (SDM) the genetic polymorphisms of the αs1, β and K-cascin and β-lactoglobulin (β-Lg) loci were determined by isoelectric focusing in agarose gels. The results of the screening were comparcd with results obtained by Larsen & Thymann (1966). In addition, the genetic linkage of the three casein loci was studied, and the association between milk protein genotypes and yields in first and second lactations of milk, fat and protein were investigated.The distribution of genotypes of all four milk protein Systems was different from breed to breed.For Jersey cows, significant differences in the gene frequencies from the results of the 1966 investigation were found for αs1 and K-casein and β-Lg. For SDM cows a change in the K-casein frequency had occurred whereas for RDM cows no changes were found.Linkage between some of the casein loci was found within ail three breeds. For the RDM breed the possible linkage between αs1-casein and the other caseins could not be tested bccause nearly ail thc cows were homozygous for the αs1-cascin-B genotypes.β-Casein genotypes were associated with yield parameters in ail breeds. The A2A2 genotype of this protein gave higher yields of milk, fat, and protein in the second lactation than thc A1A1 genotype.

Human Breast Milk Contains Bovine lgG. Relationship to Infant Colic?

PEDIATRICS ◽  
1991 ◽  
Vol 87 (4) ◽  
pp. 439-444
Author(s):  
Patrick S. Clyne ◽  
Anthony Kulczycki
Keyword(s):  
Breast Milk ◽  
Human Milk ◽  
Milk Protein ◽  
Cow’S Milk ◽  
Human Breast Milk ◽  
Human Breast ◽  
Cow's Milk ◽  
Milk Samples ◽  
Infant Colic ◽  
Β Lactoglobulin

Previous studies have suggested that an unidentified cow's milk protein, other than β-lactoglobulin and casein, might play a pathogenetic role in infant colic. Therefore, a radioimmunoassay was used to analyze human breast milk and infant formula samples for the presence of bovine IgG. Milk samples from 88 of the 97 mothers tested contained greater than 0.1 µg/mL of bovine IgG. In a study group of 59 mothers with infants in the colic-prone 2- to 17-week age group, the 29 mothers of colicky infants had higher levels of bovine IgG in their breast milk (median 0.42 µg/mL) than the 30 mothers of noncolicky infants (median 0.32 µg/mL) (P &lt; .02). The highest concentrations of bovine IgG observed in human milk were 8.5 and 8.2 µg/mL. Most cow's milk-based infant formulas contained 0.6 to 6.4 µg/mL of bovine IgG, a concentration comparable with levels found in many human milk samples. The results suggest that appreciable quantities of bovine IgG are commonly present in human milk, that significantly higher levels are present in milk from mothers of colicky infants, and that bovine IgG may possibly be involved in the pathogenesis of infant colic.

scholarly journals The relevance of milk protein polymorphisms for dairy cattle breeding.

1993 ◽  
Vol 1993 ◽  
pp. 46-46
Author(s):  
Henk Bovenhuis
Keyword(s):  
Genetic Variants ◽  
Milk Protein ◽  
Production Traits ◽  
Milk Production Traits ◽  
Breeding Scheme ◽  
Cattle Breeding ◽  
Dairy Cattle Breeding ◽  
Nucleus Breeding ◽  
Selection For ◽  
Β Lactoglobulin

Several studies have shown milk protein genetic variants to be associated with manufacturing properties of milk. The main findings were that κ-casein genetic variants affect renneting time of milk and βlactoglobulin genetic variants are associated with casein number (reviewed by Grosclaude, 1988). There are reports also of associations between milk protein genetic variants and milk production traits. Results from these studies indicate that κ-casein genotypes are associated with protein content and βlactoglobulin genotypes are related to fat content (reviewed by Bovenhuis et al., 1992). Therefore, κ-casein and βlactoglobulin genotypes might be of value as selection criteria. The aim of the present study was to quantify the potential effects of selection for κ-casein and β-lactoglobulin genotypes by using stochastic simulation of a closed adult MOET nucleus breeding scheme.

Effect of the A and B variants of both αs1- and κ-casein on bovine casein micelle solvation and κ-casein content

1993 ◽  
Vol 60 (4) ◽  
pp. 505-516 ◽  
Author(s):  
Skelte G. Anema ◽  
Lawrence K. Creamer
Keyword(s):  
Genetic Variants ◽  
The Other ◽  
Casein Micelle ◽  
Lactation Period ◽  
Chromosomal Dna ◽  
Electrophoretic Method ◽  
Milk Samples ◽  
Micelle Size ◽  
Centrifugation Technique ◽  
Β Lactoglobulin

SummaryCasein micelle solvation, a micelle characteristic that is sensitive to many factors, has been measured by a centrifugation technique at 30 °C for a series of uncooled fresh skim milks at pH 6·3, 6·6, 6·9 and 7·1. The relative αs-(αs1- plus αs2-), β– and κ-casein contents of all centrifuge pellets and supernatants were determined by a standardized electrophoretic method. The calcium and phosphate contents of a number of the pellets and milk samples were also determined. Solvation of micelles from milks with various genetic variants of β-lactoglobulin (A and B), αs1-casein (A and B) and κ-casein (A and B) was often found to be lower for milks containing either the B variant of αs1-casein or the A variant of κ-casein. It was also found that these two variant caseins were associated with a lower κ-casein content of the milks and the micelles, which is consistent with the lower solvation as κ-casein is associated with smaller micelle size and greater solvation. The solvations also seemed to increase during the lactation period. It is possible that some of the other features of milk and its products that have been ascribed to the differences in functional character between the A and B variants of αs1-casein may be partly caused by the increased level of κ-casein. The reason for the association of the A variant of αs1-casein with higher concentrations of κ-casein (and micelle solvation) is not obvious but possibly the haplotype αs1-casein A, β-casein A1, κ-casein A contains a controlling sequence in the chromosomal DNA that enhances expression of the κ-casein gene.

Effects of β-lactoglobulin and κ-casein genetic variants and concentrations on syneresis of gels from renneted heated milk

1989 ◽  
Vol 56 (2) ◽  
pp. 297-301 ◽  
Author(s):  
Douglas M. McLean ◽  
Johan Schaar
Keyword(s):  
Genetic Polymorphism ◽  
Complex Formation ◽  
Genetic Variants ◽  
Milk Protein ◽  
Major Influence ◽  
Essential Requirement ◽  
Heated Milk ◽  
Cheese Curd ◽  
Processing Properties ◽  
Β Lactoglobulin

Milk protein genetic polymorphism has a major influence on the composition of milk, and on its processing properties, including yield of cheese (see Schaaret al.1985; McLeanet al.1984, 1987; McLean, 1987). However, there appears to be little information on the effects of milk protein genetic variants on syneresis of cheese curd. The effect of casein composition on syneresis was studied by Pearseet al.(1986), who found that syneresis was affected only by the level of β-casein. Syneresis is an essential requirement in cheese making from renneted or acidified milk, but is undesirable during the storage of products such as yogurt. Milk for yogurt manufacture is preheated to minimize syneresis and to give maximal firmness of the yogurt coagulum (Tamime & Deeth, 1980). Pearseet al.(1985) showed that the reduction of one-third in the extent of syneresis caused by heating artificial micelle milk (AMM) containing βlactoglobulin (β-lg) in natural concentrations was due to sulphydryl-mediated complex formation between β-lg and micellar κ-casein which appeared to interfere with the micelle–micelle interactions responsible for syneresis. The results presented here were part of a study which investigated the effects of κcasein and κ-lg genetic variants and concentrations on syneresis of curd formed from renneted heated AMM.

scholarly journals Genetic Variants of k-Casein and β-Lactoglobulin Genes and Their Association with Protein and Milk Components of Holstein Friesian Cows at Small Farmers in Lembang, West Java

2017 ◽  
Vol 2 (6) ◽  
pp. 86 ◽  
Author(s):  
Anggraeni Anggraeni ◽  
A. Anneke ◽  
H.S. Nury ◽  
E. Andreas ◽  
C. Sumantri
Keyword(s):  
Genetic Variants ◽  
Milk Protein ◽  
Restriction Enzymes ◽  
Dairy Farmers ◽  
West Java ◽  
Holstein Friesian ◽  
Pcr Rflp ◽  
Milk Components ◽  
Milk Component ◽  
Β Lactoglobulin

Genetic variants of CSN3 and LGB genes and their effects on protein and milk components were studied in Holstein Friesian at small dairy farmers in Lembang District, West Java, Indonesia.  Allelic variants were identified by PCR-RFLP technique using restriction enzymes of Pst I for the CSN3 gene and Hae III for the LGB gene.  The CSN3 gene was dominated by AB genotype.   Milk protein was not affected by genotypes of the two genes.  Only fat content was significantly affected (P <0.05) by the CSN3 gene with AB cows having the highest fat to AA and BB cows (3.76% vs. 3.26% and 3.34%). Keywords: CSN3 gene; LGB gene; milk protein; and milk component.

scholarly journals Milk protein polymorphism in Swiss dairy cattle

1993 ◽  
Vol 2 (5) ◽  
pp. 423-429
Author(s):  
Fawzy Taha ◽  
Zdenko Puhan
Keyword(s):  
Dairy Cattle ◽  
Milk Yield ◽  
Milk Protein ◽  
Allele Frequencies ◽  
Cow Milk ◽  
Brown Swiss ◽  
Milk Samples ◽  
Brown Cattle ◽  
Simmental Cattle ◽  
Β Lactoglobulin

Individual cow milk samples from (a) 208 original Swiss Simmental (OSS), (b) 220 of their crosses (Simmental cattle = FV) with American Red Holstein (RH), (c) 215 original Swiss Brown (OSB) and (d) 390 of their crosses (Brown cattle = BV) with American Brown Swiss (BS) were genotyped for the variants of milk caseins (Cn) and β-Lactoglobulin (β-Lg). In addition, the association between κ-Cn genotypes and milk yield was studied. Reasonable differences in the allele frequencies were found between the breeds. Compared to pure-bred OSS, crossing with RH resulted in a decrease in the frequencies of αs1-Cn C, β-Cn B and κ-Cn B and in an increased frequency of β-Lg B. Within OSB, increased crossing with BS resulted in a decrease in the frequencies of αs1-Cn C and β-Cn B and in increased frequencies of κ-Cn B and β-Lg B. A significant association between the κ-Cn locus and milk yield could only be shown for the OSS breed.

Sign in / Sign up

Export Citation Format

Share Document