| 1. |
- Andrén, Anders, et al.
(författare)
-
The occurrence of noncoagulating milk and the association of bovine milk coagulation properties with genetic variants of the caseins in 3 Scandinavian dairy breeds
- 2013
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 96:8, s. 4830-4842
-
Tidskriftsartikel (refereegranskat)abstract
- Substantial variation in milk coagulation properties has been observed among dairy cows. Consequently, raw milk from individual cows and breeds exhibits distinct coagulation capacities that potentially affect the technological properties and milk processing into cheese. This variation is largely influenced by protein composition, which is in turn affected by underlying genetic polymorphisms in the major milk proteins. In this study, we conducted a large screening on 3 major Scandinavian breeds to resolve the variation in milk coagulation traits and the frequency of milk with impaired coagulation properties (noncoagulation). In total, individual coagulation properties were measured on morning milk collected from 1,299 Danish Holstein (DH), Danish Jersey (DJ), and Swedish Red (SR) cows. The 3 breeds demonstrated notable interbreed differences in coagulation properties, with DJ cows exhibiting superior coagulation compared with the other 2 breeds. In addition, milk samples from 2% of DH and 16% of SR cows were classified as noncoagulating. Furthermore, the cows were genotyped for major genetic variants in the alpha(S1)- (CSN1S1), beta- (CSN2), and kappa-casein (CSN3) genes, revealing distinct differences in variant frequencies among breeds. Allele I of CSN2, which had not formerly been screened in such a high number of cows in these Scandinavian breeds, showed a frequency around 7% in DH and DJ, but was not detected in SR. Genetic polymorphisms were significantly associated with curd firming rate and rennet coagulation time. Thus, CSN1S1 C, CSN2 B, and CSN3 B positively affected milk coagulation, whereas CSN2 A(2), in particular, had a negative effect. In addition to the influence of individual casein genes, the effects of CSN1S1-CSN2-CSN3 composite genotypes were also examined, and revealed strong associations in all breeds, which more or less reflected the single gene results. Overall, milk coagulation is under the influence of additive genetic variation. Optimal milk for future cheese production can be ensured by monitoring the frequency of unfavorable variants and thus preventing an increase in the number of cows producing milk with impaired coagulation. Selective breeding for variants associated with superior milk coagulation can potentially increase raw milk quality and cheese yield in all 3 Scandinavian breeds.
|
|
| 2. |
- Ardö, Ylva, et al.
(författare)
-
Studies of peptidolysis during early maturation and its influence on low-fat cheese quality
- 1989
-
Ingår i: Milchwissenschaft. - 0026-3788. ; 44:8, s. 485-490
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of peptidolysis during early cheese ripening were studied in a low-fat (10% fat), round-eyed, semi-hard cheese using gel permeation chromatography and determinations of N content in cheese extracts. Addition of a heat-treated culture of Lactobacillus helveticus enhanced the peptidolytic activity even during the first weeks of cheese ripening. An aminopeptidase was found to have the necessary properties to cause the observed peptidolysis in the cheese after leakage from the cells. In the cheeses with heat-treated lactobacilli there were marked increases in cheese flavour intensity and an elimination of bitterness compared with control cheeses. The de-bittering effects due to high hydrolytic activities against peptides are discussed as well as effects of increased extracellular concn. of amino acids and/or small peptides on lactic acid bacteria metabolism. It is suggested that some stimulation of the fundamental functions of the starter bacteria might be necessary to achieve the desired flavour development in this type of low-fat cheese and that enhancement of peptidolysis during the very first weeks of cheese ripening is one method.
|
|
| 3. |
- Chen, Jun, et al.
(författare)
-
Antioxidant capacity of bovine milk as assayed by spectrophotometric and amperometric methods
- 2003
-
Ingår i: International Dairy Journal. - 0958-6946. ; 13:12, s. 927-935
-
Tidskriftsartikel (refereegranskat)abstract
- The total antioxidant capacity (TAC) of bovine milk, whey, and low-molecular-weight (LMW) fractions of whey was investigated using spectrophotometric methods including an ABTS-based method (reduction of the cation radical of 2,2′-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid)) and a FRAP method (reduction of Fe3+). Significant antioxidant capacity in milk and whey was demonstrated by the ABTS method (TAC(ABTS)), and it apparently increased with increasing pH. TAC (ABTS) was several-fold higher in milk than in whey, which had a slightly higher TAC than a LMW fraction prepared from it. Also the FRAP method could be used to demonstrate TAC in whey, although the low pH necessary for this method led to some protein precipitation. Most of the ferric-reducing activity of whey was found in the LMW fraction. The TAC values obtained using these methods were also compared to those obtained using a newly developed flow-injection amperometric (FIAmp) procedure for LMW fractions. High correlations were found for the TAC values of LMW samples obtained by the ABTS, FRAP and FIAmp methods (R2>0.8, P<0.001). Furthermore, to identify the major antioxidants in the LMW fraction, it was treated by uricase. Since most of the TAC (using ABTS, FRAP and FIAmp methods) was removed by uricase treatment, it could be concluded that urate is the major antioxidant in the LMW fraction. Also the effect of heat treatment on TAC in milk and whey was monitored. After heating of whey at 63°C for 1 h, TAC(ABTS) tended to increase by at least 20%, while TAC(FRAP) was not significantly changed. In milk, TAC(ABTS) remained constant during the same heat treatment. It is concluded that the methods tested gave the most reliable results for the LMW fraction of whey and that the use of several methods is necessary to characterise the antioxidant capacity of milk.
|
|
| 4. |
|
|
| 5. |
- Elfstrand, Lidia, et al.
(författare)
-
Immunoglobulins, growth factors and growth hormone in bovine colostrum and the effects of processing
- 2002
-
Ingår i: International Dairy Journal. - 0958-6946. ; 12:11, s. 879-887
-
Tidskriftsartikel (refereegranskat)abstract
- In colostrum collected 0-80 h postpartum the contents of immunoglobulins (Igs), transforming growth factor beta-2 (TGF-beta2), insulin-like growth factor-1 (IGF-1) and growth hormone (GH) were analysed. Colostrum initially contained 90 mg mL(-1) IgG1, 2.8 mg mL(-1) IgG2, 1.6 mg mL(-1) IgA, 4.5 mg mL(-1) IgM, and these concentrations declined by 92%, 87%, 93% and 84%, respectively, in the samples collected later. Of the growth factors, colostrum initially contained 289-310 ng mL(-1) TGF-beta2 and the concentration diminished to 66 ng mL(-1). The content of IGF-1 and GH postpartum decreased from 870 to 150 ng mL(-1), and from 0.17 to < 0.03 ng mL(-1), respectively. Heat treatment and freeze-drying of colostral whey decreased the content of Igs to 75%, while the contents of IGF-1 and TGF-beta2 were unaffected. A similar processing, including filtration steps reduced also the IGF-1 and TGF-beta2 by 25%. IgM seems to be the most sensitive of the Igs to processing. (C) 2002 Elsevier Science Ltd. All rights reserved.
|
|
| 6. |
|
|
| 7. |
- Freiburghaus, Catja, et al.
(författare)
-
Identification of ubiquitin in bovine milk and its growth inhibitory effects on human cancer cell lines.
- 2010
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 93:8, s. 3442-3452
-
Tidskriftsartikel (refereegranskat)abstract
- Bovine milk is associated with improved health and reduced risk of several diseases, among them cancer. Milk is a complex mixture of known and unknown components. The components and the mechanisms that contribute to the cancer-preventive effects are largely unknown. We set out to find new peptides in milk and identified ubiquitin (Ub) using matrix-assisted laser desorption ionization-time of flight mass spectrometry and Western blot. Using quantitative Western blot, we estimated the Ub concentration to be about 0.003 micromol/L in milk. We then decided to investigate the effect of treating human colon cancer CaCo-2 cells with Ub, using higher concentrations than in milk. CaCo-2 cells treated with 0.02 to 2.0 micromol/L Ub showed significantly decreased proliferation compared with untreated control cells. A higher growth inhibitory effect than in CaCo-2 cells was found in the neuroblastoma cell line SH-SY5Y treated with 0.02 to 0.2 micromol/L Ub. A bromodeoxyuridine DNA flow cytometric method was used to study cell cycle kinetics in Ub-treated CaCo-2 cells. The data point toward a prolongation of the G(1) phase. The levels of several cell cycle regulatory proteins were affected. Our data point to Ub possibly being one of the components in milk reducing the risk of cancer.
|
|
| 8. |
- Freiburghaus, Catja, et al.
(författare)
-
Lactoferricin treatment decreases the rate of cell proliferation of a human colon cancer cell line.
- 2009
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 92:6, s. 2477-2484
-
Tidskriftsartikel (refereegranskat)abstract
- Food components modify the risk of cancer at a large number of sites but the mechanism of action is unknown. In the present investigation, we studied the effect of the peptide lactoferricin derived from bovine milk lactoferrin on human colon cancer CaCo-2 cells. The cells were either untreated or treated with 2.0, 0.2, or 0.02 microM lactoferricin. Cell cycle kinetics were investigated with a bromodeoxyuridine DNA flow cytometric method. The results show that lactoferricin treatment slightly but significantly prolonged the S phase of the cell cycle. Lactoferricin treatment lowered the level of cyclin E1, a protein involved in the regulation of genes required for G(1)/S transition and consequently for efficient S phase progression. The slight prolongation of the S phase resulted in a reduction of cell proliferation, which became more apparent after a long treatment time.
|
|
| 9. |
|
|
| 10. |
- Glantz, Maria, et al.
(författare)
-
Bovine chromosomal regions affecting rheological traits in acid-induced skim milk gels.
- 2015
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 98:2, s. 1273-1285
-
Tidskriftsartikel (refereegranskat)abstract
- The production of fermented milk products has increased worldwide during the last decade and is expected to continue to increase during the coming decade. The quality of these products may be optimized through breeding practices; however, the relations between cow genetics and technological properties of acid milk gels are not fully known. Therefore, the aim of this study was to identify chromosomal regions affecting acid-induced coagulation properties and possible candidate genes. Skim milk samples from 377 Swedish Red cows were rheologically analyzed for acid-induced coagulation properties using low-amplitude oscillation measurements. The resulting traits, including gel strength, coagulation time, and yield stress, were used to conduct a genome-wide association study. Single nucleotide polymorphisms (SNP) were identified using the BovineHD SNPChip (Illumina Inc., San Diego, CA), resulting in almost 621,000 segregating markers. The genome was scanned for putative quantitative trait loci (QTL) regions, haplotypes based on highly associated SNP were inferred, and the additive genetic effects of haplotypes within each QTL region were analyzed using mixed models. A total of 8 genomic regions were identified, with large effects of the significant haplotype explaining between 4.8 and 9.8% of the phenotypic variance of the studied traits. One major QTL was identified to overlap between gel strength and yield stress, the QTL identified with the most significant SNP closest to the gene coding for κ-casein (CSN3). In addition, a chromosome-wide significant region affecting yield stress on BTA 11 was identified to be colocated with PAEP, coding for β-lactoglobulin. Furthermore, the coagulation properties of the genetic variants within the 2 genes were compared with the coagulation properties identified by the patterns of the haplotypes within the regions, and it was discovered that the haplotypes were more diverse and in one case slightly better at explaining the phenotypic variance. Besides these significant QTL comprising the 2 milk proteins, 3 additional genes are proposed as possible candidates, namely RAB22A, CDH13, and STAT1, and all have previously been found to be expressed in the mammary gland. To our knowledge, this is the first attempt to map QTL regions for acid-induced coagulation properties.
|
|
