Effects of κ-casein genetic variants and lactation number on the renneting properties of individual milks

1984 ◽  
Vol 51 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Johan Schaar
Keyword(s):  
Genetic Variants ◽  
Considerable Degree ◽  
Coagulation Time ◽  
Milk Samples ◽  
Rennet Coagulation

SummaryThe effects of κ-casein genetic variants, lactation number, pH and casein content on the renneting properties of individual milks were studied. Rennet coagulation time (RCT) and curd firmness were determined with the aid of a lactodynamograph and the results statistically analysed. Renneting properties were strongly related to κ-casein variants and lactation number, with κ-casein B and higher lactation numbers giving shorter RCT and increased curd firmness, the effects on curd firmness being more pronounced. The effect of κ-casein variant on RCT could be eliminated by reducing pH and adding CaCl2 to the milk samples. The effect on curd firmness was not altered by this treatment, however. The results show that the renneting properties of individual milks are to a considerable degree genetically controlled.

Effects of dairy factory, milk casein content and titratable acidity on coagulation properties in Trentingrana dairy industry

2016 ◽  
Vol 83 (2) ◽  
pp. 242-248 ◽  
Author(s):  
Mauro Penasa ◽  
Valentina Toffanin ◽  
Nicola Cologna ◽  
Martino Cassandro ◽  
Massimo De Marchi
Keyword(s):  
Fixed Effects ◽  
Titratable Acidity ◽  
Testing Time ◽  
Technological Properties ◽  
Coagulation Time ◽  
Milk Samples ◽  
Rennet Coagulation ◽  
Milk Coagulation ◽  
Milk Casein

The objective of the present study was to investigate the effect of environmental factors, milk casein content and titratable acidity on milk coagulation properties (MCP) of samples routinely collected in the Trento province (northeast Italy) under field conditions. Rennet coagulation time (RCT, min), curd-firming time (k20, min) and curd firmness (a30, mm) were determined by Formagraph on 14 971 samples from 635 herds associated to 17 dairy factories. Besides MCP, fat, protein, and casein percentages, titratable acidity (TA), and somatic cell and bacterial counts were available. A standardised index of milk aptitude to coagulate (IAC) was derived using information of RCT and a30. An analysis of variance was conducted on MCP and IAC using a fixed effects linear model. Approximately 3% of milk samples did not form a curd within the testing time (30 min) and k20 was missing for 26% of milks. The percentage of samples without information on k20 largely differed among dairy factories (1·7–20·9%). Significant differences were estimated between the best and the worst dairy factory for RCT (−2 min), k20 (−1·2 min), a30 (+3·4 mm) and IAC (+2·6 points). Milk casein content and TA were important factors in explaining the variation of MCP and IAC, supporting the central role of these two traits on technological properties. The Trento province is heterogeneous in terms of dairy systems and this could explain the differences among dairy factories.

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.

scholarly journals Allele frequencies and genotypes of kappa casein (CSN3) and their association with chemical composition and coagulation properties of milk in Brown cattle

2021 ◽  
Vol 13 (4) ◽  
pp. 352-356
Author(s):  
T. Angelova ◽  
J. Krastanov ◽  
D. Yordanova
Keyword(s):  
Milk Fat ◽  
Milk Proteins ◽  
Allele Frequencies ◽  
Sample Collection ◽  
Coagulation Time ◽  
Coagulation Activity ◽  
Tissue Samples ◽  
Milk Samples ◽  
Rennet Coagulation ◽  
Brown Cattle

Abstract. The aim of the present study was to evaluate allele frequencies and genotypes of kappa casein (CSN3) and their association with milk quality and coagulation properties in Brown cattle. Milk proteins’ polymorphism was found out in 155 tissue samples from cows reared at 4 farms. The analysis of milk composition was done in the lab of the Agriculture Institute – Stara Zagora on Lactoscan ultrasound milk analyzer, whereas coagulation properties of individual milk samples were evaluated on a Computerized Renneting Metter – Polo Trade, Italy. Milk samples were obtained by milk meters. The milk was analysed within 3 hours after sample collection. Naturen Plus 215/0.8L chymosin was used, with milk coagulation activity of 215 IMCU/ml. During the study, the following parameters were studied: milk fat and protein contents (%), rennet coagulation time (RCT, min), curd firmness (а30, mm) and curd firming time (k20, min). Kappa casein (CSN3) is characterised by five genotypes – АА, АВ, ВВ, АН and ВН, the frequency of which varied within various ranges. The milk of cows with genotype AB was characterized by the highest content of fat and protein: 4.85% and 5.00%, respectively. The milk of heterozygous cows from genotype AB demonstrated the longest rennet coagulation time – 18.04 min. The animals carrying the H allele produced milk with the highest curd firmness – 37.00 mm.

scholarly journals Relationships between milk yield, quality and coagulation properties with kappa-casein (к-CN) genotypes of Bulgarian Rhodope cattle breed

2019 ◽  
Vol 11 (3) ◽  
pp. 203-206
Author(s):  
I. Mehandzhiyski ◽  
Т. Angelova ◽  
D. Yordanova ◽  
J. Krastanov
Keyword(s):  
Dairy Cows ◽  
Protein Content ◽  
Milk Yield ◽  
Tissue Sample ◽  
Milk Proteins ◽  
Coagulation Time ◽  
Tissue Samples ◽  
Milk Samples ◽  
Rennet Coagulation ◽  
Yield Quality

Abstract. The aim of the present study was to establish the association between different к-CN genotypes with milk yield, quality and coagulation properties in dairy cows of Bulgarian Rhodope breed. For determination of milk proteins polymorphism and its relationship with individual coagulation properties of milk and its quality, 136 milk samples from Bulgarian Rhodope dairy cows reared in 4 farms were collected. The visit to the farms and the taking of the milk samples took place between May and June 2009. Animal milk is based on daily milking on the relevant control day of the current lactation. During the morning milking, 50mL samples were collected without preservative, stored in cooling bags and analyzed in the specialized lab at the Agricultural Institute, Stara Zagora by Computerized Renneting Metter. The evaluated parameters of milk coagulation properties were: rennet coagulation time (RCT, min); curd firming time (K20, min) and curd firmness (A30, mm). Milk proteins polymorphism was identified by tissue samples collection from 136 cows. To this end, specialized pliers and marks with a vial containing desiccant were used. With this technique, the tissue sample is obtained and sealed at the time of identification of the animal. After collection, tissue samples were shipped to the University in Padova, Italy for PCR-RFLP analysis. DNA was purified using a Maxwell®16 Tissue DNA purification kit (Promega) according to the manufacturer’s instructions. Data were analyzed using descriptive statistical analysis (SYSTAT 13). The results obtained give reason to the following conclusions: The highest milk yield was established in cows from the AH genotype – 16kg, whereas the lowest value was detected in cows from the BH genotype – 12.83kg. Homozygous cows from the BB genotype produced milk with the highest fat content – 5.11%, whereas heterozygous from the BH genotype: milk with the lowest protein content – 3.16%. The cows from the AH genotypes were outlined with the lowest milk fat and protein content. The longest rennet coagulation time (RCT) was observed in АА and АН genotypes, the longest curd firming time (К20) – in genotype AH, the highest curd firmness (А30) – in the milk of cows from the AB and BB genotypes.

Physical properties of mammary secretions in relation to chemical changes during transition from colostrum to milk

2004 ◽  
Vol 71 (3) ◽  
pp. 263-272 ◽  
Author(s):  
Birgitte D Madsen ◽  
Morten D Rasmussen ◽  
Mette O Nielsen ◽  
Lars Wiking ◽  
Lotte B Larsen
Keyword(s):  
Physical Properties ◽  
Cell Count ◽  
Somatic Cell Count ◽  
Potential Method ◽  
Early Lactation ◽  
Coagulation Time ◽  
Chemical Changes ◽  
Milk Samples ◽  
Rennet Coagulation ◽  
Physical And Chemical

We examined the physical and chemical changes in milk during early lactation, and how these changes were affected by leaving one quarter unmilked in either the first or second milking, with the purpose of discriminating between colostrum and normal milk. Milk samples were collected from each quarter of 17 cows during the first 5 d after calving and then after about 7 d and 14 d. Samples were analysed for somatic cell count (SCC), fat, protein, casein, lactose, IgG1, colour, plasmin, pH and coagulation properties. Large variations occurred in both chemical and physical properties throughout the study period. Within six milkings, the concentration of casein decreased by 60%, IgG1 by 94%, and lactose increased by 34%. At milking number 6, rennet coagulation time was lowest and curd firmness was highest. The pH increased from 6·4 to 6·7 over the period of the experiment, and the colour changed from yellow (reddish) to white. Coagulation properties and the pH fell within the range of normal milk after five milkings. Measurement of colour and density appeared to be a potential method for detection of milk unsuitable for the dairy factory. Effects of omitting one quarter in one milking differed between milk components, but seemed to be of little importance to the physical properties.

scholarly journals Milk protein genotypes and milk coagulation properties of Estonian Native cattle

2008 ◽  
Vol 16 (3) ◽  
pp. 222 ◽  
Author(s):  
I. JÕUDU ◽  
M. HENNO ◽  
S. VÄRV
Keyword(s):  
Genetic Variation ◽  
Milk Protein ◽  
Coagulation Parameters ◽  
Milk Samples ◽  
Cattle Breeds ◽  
Rennet Coagulation ◽  
Native Cattle ◽  
Milk Coagulation

The genetic variation of ás1-, â- and ê-caseins and b-lactoglobulin was determined and their effects on the rennet coagulation properties were examined using 335 milk samples from 118 Estonian Native (EN) cows. We found 16 aggregate casein genotypes (ás1-, â-, ê-caseins), of which four . namely, BB A2A2 AA (21.2%), BB A1A2 AB (16.9%), BB A1A2 AA (14.4%), and BB A2A2 AB (10.2%) – occurred among nearly two-thirds of the analysed cows. Aggregate casein genotype had a significant overall effect on rennet coagulation parameters. Better rennet coagulation properties were found for aggregate casein genotypes CC A2A2 AB and BC A1A2 BB, among frequent genotypes for BB A1A2 AB. Of the cattle breeds raised in Estonia, milk from EN had the best coagulation properties and highest frequency of favourable ê-Cn B allele.;

Effects of the CSN1AG allele on the clotting time of cow milk and on the rheological properties of rennet-curd

2001 ◽  
Vol 68 (1) ◽  
pp. 63-70 ◽  
Author(s):  
PRIMO MARIANI ◽  
ANDREA SUMMER ◽  
PAOLA DI GREGORIO ◽  
ANDREA RANDO ◽  
ENRICO FOSSA ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Rheological Properties ◽  
Titratable Acidity ◽  
Cow Milk ◽  
Clotting Time ◽  
Somatic Cell Counts ◽  
Milk Samples ◽  
Cell Counts ◽  
Normal Ranges ◽  
Rennet Coagulation

The aim of this research was to study the effects of the CSN1AG allele on the main rennet coagulation properties of milk. The study was carried out on individual milk samples with low αs1-casein obtained from 19 Italian Brown cows heterozygous for the CSN1AG allele (seventeen CSN1A BG and two CSN1A CG) from four herds in the province of Parma (Italy). Control cows (sixteen CSN1A BB and three CSN1A BC) giving milk with normal αs1-casein levels were chosen from within the same herds in order to establish pairs of cows with identical environment and management conditions, and comparable lactation stages and numbers. Individual milk samples from single pairs of cows with somatic cell counts and lactose and chloride levels within the normal ranges were collected and analysed in parallel. Rennet coagulation properties of milk were analysed using Formagraph and Gel Tester. Milk from low αs1-casein cows was characterized by lower casein content, lower titratable acidity and a higher proportion of κ-casein in total casein. The clotting time of this milk was ∼ 23% lower than that obtained with milk from normal αs1-casein cows. Rennet curd from low αs1-casein milk was obtained more rapidly and had a higher final firmness: curd-firming time was ∼ 35% lower and curd firmness measured 30 min after rennet addition was ∼ 27 % higher compared with that for normal αs1-casein milk. In addition, curd from low αs1-casein milk had a higher resistance to compression. These results suggest that, although a role for the CSN2 locus cannot be definitely excluded, the CSN1AG allele can considerably affect the main rennet coagulation properties of milk.

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.

Effect of casein micelle composition and casein dephosphorylation on coagulation and syneresis

1986 ◽  
Vol 53 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Martin J. Pearse ◽  
Peter M. Linklater ◽  
Robert J. Hall ◽  
Antony G. Mackinlay
Keyword(s):  
Adverse Effect ◽  
Casein Micelle ◽  
Coagulation Time ◽  
Rennet Coagulation ◽  
Phosphate Groups

SUMMARYThe effect of varying the casein composition of artificial micelle milk on rennet coagulation time and syneresis was examined in order to determine whether either of these processes is dependent on the concentration of particular casein components. It was found that the levels of κ-and β-caseins had a significant effect on coagulation, whereas syneresis was only affected by the level of β-casein. Partial dephosphorylation of preformed micelles or the incorporation of dephosphorylated or partly dephosphorylated β-casein into artificial micelle milk was found to have an adverse effect on both coagulation and syneresis. It was concluded that the phosphate groups of casein, particularly those of β-casein, are directly involved in the micelle-micelle interactions which occur during coagulation and syneresis.

scholarly journals Changes of quality of rennets during storing

2012 ◽  
Vol 60 (6) ◽  
pp. 189-196
Author(s):  
Monika Kozelková ◽  
Miroslav Jůzl ◽  
Táňa Lužová ◽  
Květoslava Šustová ◽  
Aneta Bubeníčková
Keyword(s):  
Near Infrared ◽  
Color Change ◽  
Coagulation Time ◽  
Time Activity ◽  
Spectrophotometric Methods ◽  
Color Changes ◽  
Rennet Coagulation ◽  
Total Color Change ◽  
Instrumental Methods

This work deals about evaluation of qualitative parameters of rennets. During the six months storing of rennets were determined following qualitative parameters: pH, rennet coagulation time, activity (strange) of rennet and dose of rennet, and finally were used instrumental methods: Near infrared spectroscopy (NIR) for recognizing age of rennets and spectrophotometric methods of determining the color of rennets. The theory found in the references suggests, that the activity of rennet should decrease by an average of 1–2 % per month, but the results are showing, that are changing quality of rennets namely mostly activity (strange) of rennet, which was decreased by 33% per half year. In analysis of color of rennets weren’t observed major changes by the whole group. Some statistical differences were detected in the partial values L*a*b*, most advantageous were evaluation by rennet total color change during storage, which were higher than noticeable change in four samples. The least color changes (P > 0.05) were observed in microbial rennets, with no values observed (ΔEab < 2) that can be recognized even by the human eye when subjected to parallel comparison. It was found that the NIR analysis can be used to recognizing of rennets, which are different ages.

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