| 1. |
- Glantz, Maria, et al.
(författare)
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Impact of protease and lipase activities on quality of Swedish raw milk
- 2020
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946. ; 107
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Tidskriftsartikel (refereegranskat)abstract
- An increasing demand for dairy products with long shelf-life is foreseen. A limiting factor for maintaining high quality of these products is the activity of spoilage enzymes during storage. Lipase and protease activities in Swedish raw milk at farm and dairy level were investigated, analysing milk samples from three geographical regions and two seasons. Lipase activity in milk at farm level was affected by regional and seasonal variations, whereas at dairy level only season had an effect. Lipase activity was positively correlated with ionic calcium. For protease activity, no effect of either region or season was seen. Degradation products, e.g., free fatty acids, peptides and plasmin proteolysis products, varied differently between season and geographical origin at both farm and dairy level. The results indicate that lipase and protease activities are important for raw milk quality, while ionic calcium might be a future indicator for milk fat stability.
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| 2. |
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| 3. |
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| 4. |
- Sunds, Anne Vuholm, et al.
(författare)
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Comparison of bovine milk oligosaccharides in native North European cattle breeds
- 2021
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946. ; 114
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Tidskriftsartikel (refereegranskat)abstract
- Milk oligosaccharides are of high interest due to their bioactive properties. This study is the first to characterise milk oligosaccharides from native North European cattle breeds, as represented by 80 milk samples collected from eight native breeds originated from Norway (Norwegian Doela cattle and Norwegian Telemark cattle), Sweden (Swedish Mountain cattle), Denmark (Danish Red anno 1970), Iceland (Icelandic cattle), Lithuania (native Lithuanian Black and White) and Finland (Western Finncattle and Eastern Finncattle). Using high-performance liquid-chromatography chip/quadrupole time-of-flight mass-spectrometry, 18 unique monosaccharide compositions and a multitude of isomers were identified. No N-glycolylneuraminic acid was identified among these breeds. Western Finncattle milk was most abundant in neutral, acidic and fucosylated oligosaccharides. Further, Eastern Finncattle milk was significantly higher in acidic oligosaccharides and Icelandic cattle milk significantly higher in fucosylated oligosaccharides, compared to the mean. This study highlights specific native breeds of particular interest for future exploitation of milk oligosaccharides and breeding strategies.
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| 5. |
- Sunds, Anne Vuholm, et al.
(författare)
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Naturally occurring glycosidases in milk from native cattle breeds : Activity and consequences on free and protein bound-glycans
- 2021
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Ingår i: Metabolites. - : MDPI AG. - 2218-1989. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about the extent of variation and activity of naturally occurring milk glycosidases and their potential to degrade milk glycans. A multi-omics approach was used to investigate the relationship between glycosidases and important bioactive compounds such as free oligo-saccharides and O-linked glycans in bovine milk. Using 4-methylumbelliferone (4-MU) assays activities of eight indigenous glycosidases were determined, and by mass spectrometry and1H NMR spectroscopy various substrates and metabolite products were quantified in a subset of milk samples from eight native North European cattle breeds. The results showed a clear variation in glycosidase activities among the native breeds. Interestingly, negative correlations between some glycosidases including β-galactosidase, N-acetyl-β-D-glucosaminidase, certain oligosaccharide isomers as well as O-linked glycans of κ-casein were revealed. Further, a positive correlation was found for free fucose content and α-fucosidase activity (r = 0.37, P-value < 0.001) indicating cleavage of fucosylated glycans in milk at room temperature. The results obtained suggest that milk glycosidases might partially degrade valuable glycans, which would result in lower recovery of glycans and thus represent a loss for the dairy ingredients industry if these activities are pronounced.
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| 6. |
- Andersson, Ida Marie, et al.
(författare)
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Effects of feed composition, protein denaturation and storage of milk serum protein/lactose powders on lactosylation
- 2021
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Ingår i: International Journal of Food Science and Technology. - : Wiley. - 0950-5423 .- 1365-2621. ; 56:1, s. 480-492
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Tidskriftsartikel (refereegranskat)abstract
- During whey powder production, the feed is subjected to several heat treatments which can cause lactosylation of proteins. In this study, lactosylation of whey proteins was evaluated in spray-dried powders before and after storage by varying the native protein fraction as well as the serum protein/lactose ratio in the powders. The lactosylation of native α-lactalbumin and β-lactoglobulin in the powders before storage was not affected to a large extent by the protein denaturation or if the feed had been heat treated in a high or low lactose environment. After storage (relative humidity of 23.5%, 30 °C, 25 days), the kinetic of lactosylation tended to increase with increasing native protein fraction and bulk protein content in the powders. An explanation could be that proteins dissolved in the lactose glassy structure might have a lower reactivity, while proteins present in the protein glassy structure with dissolved lactose may display higher lactosylation reactivity.
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| 7. |
- Andrén, Anders, et al.
(författare)
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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
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 96:8, s. 4830-4842
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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.
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| 8. |
- Augustin, Hanna, et al.
(författare)
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Late Pregnancy Vitamin D Deficiency is Associated with Doubled Odds of Birth Asphyxia and Emergency Caesarean Section: A Prospective Cohort Study
- 2020
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Ingår i: Maternal and Child Health Journal. - : Springer Science and Business Media LLC. - 1092-7875 .- 1573-6628. ; 24, s. 1412-1418
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this prospective cohort study was to investigate the associations between maternal vitamin D status in late pregnancy and emergency caesarean section (EMCS) and birth asphyxia, in a population based sample of women in Sweden. Methods Pregnant women were recruited at the antenatal care in Sweden and 1832 women were included after exclusion of miscarriages, terminated pregnancies and missing data on vitamin D status. Mode of delivery was retrieved from medical records. EMCS was defined as caesarean section after onset of labour. Birth asphyxia was defined as either 5 min Apgar score < 7 or arterial umbilical cord pH < 7.1. Serum was sampled in the third trimester of pregnancy (T3) and 25-hydroxyvitamin D (25OHD) was analysed by liquid chromatography tandem mass spectrometry. Vitamin D deficiency was defined as 25OHD < 30 nmol/L, and associations were studied using logistic regression analysis and expressed as adjusted odds ratios (AOR). Results In total, 141 (7.7%) women had an EMCS and 58 (3.2%) children were born with birth asphyxia. Vitamin D deficiency was only associated with higher odds of EMCS in women without epidural anaesthesia (AOR = 2.01, p = 0.044). Vitamin D deficiency was also associated with higher odds of birth asphyxia (AOR = 2.22, p = 0.044). Conclusions for Practice In this Swedish prospective population-based cohort study, vitamin D deficiency in late pregnancy was associated with doubled odds of birth asphyxia and with EMCS in deliveries not aided by epidural anaesthesia. Prevention of vitamin D deficiency among pregnant women may reduce the incidence of EMCS and birth asphyxia. The mechanism behind the findings require further investigation.
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| 9. |
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| 10. |
- Bärebring, Linnea, et al.
(författare)
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Preeclampsia and Blood Pressure Trajectory during Pregnancy in Relation to Vitamin D Status
- 2016
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Every tenth pregnancy is affected by hypertension, one of the most common complications and leading causes of maternal death worldwide. Hypertensive disorders in pregnancy include pregnancy-induced hypertension and preeclampsia. The pathophysiology of the development of hypertension in pregnancy is unknown, but studies suggest an association with vitamin D status, measured as 25-hydroxyvitamin D (25(OH) D). The aim of this study was to investigate the association between gestational 25(OH) D concentration and preeclampsia, pregnancy-induced hypertension and blood pressure trajectory. This cohort study included 2000 women. Blood was collected at the first (T1) and third (T3) trimester (mean gestational weeks 10.8 and 33.4). Blood pressure at gestational weeks 10, 25, 32 and 37 as well as symptoms of preeclampsia and pregnancy-induced hypertension were retrieved from medical records. Serum 25(OH) D concentrations (LC-MS/MS) in T1 was not significantly associated with preeclampsia. However, both 25(OH) D in T3 and change in 25 (OH) D from T1 to T3 were significantly and negatively associated with preeclampsia. Women with a change in 25(OH) D concentration of >= 30 nmol/L had an odds ratio of 0.22 (p = 0.002) for preeclampsia. T1 25(OH) D was positively related to T1 systolic (beta = 0.03, p = 0.022) and T1 diastolic blood pressure (beta = 0.02, p = 0.016), and to systolic (beta = 0.02, p = 0.02) blood pressure trajectory during pregnancy, in adjusted analyses. There was no association between 25(OH) D and pregnancy-induced hypertension in adjusted analysis. In conclusion, an increase in 25(OH) D concentration during pregnancy of at least 30 nmol/L, regardless of vitamin D status in T1, was associated with a lower odds ratio for preeclampsia. Vitamin D status was significantly and positively associated with T1 blood pressure and gestational systolic blood pressure trajectory but not with pregnancy-induced hypertension.
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| 11. |
- Bärebring, Linnea, et al.
(författare)
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Sociodemographic factors associated with dietary supplement use in early pregnancy in a Swedish cohort.
- 2018
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Ingår i: The British journal of nutrition. - 1475-2662. ; Jan;119:1, s. 90-95
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Tidskriftsartikel (refereegranskat)abstract
- Sociodemographic factors have been associated with dietary supplement use among pregnant women but few data exist in a Swedish population. This study aimed to identify factors associated with overall supplement use as well as use of folic acid, vitamin D and n-3 in early pregnancy. Women in the first trimester of pregnancy were included at registration to the antenatal care in 2013-2014 (n 2109). Information regarding supplement use as well as sociodemographic and anthropometric data were obtained from questionnaires and medical records. Multivariable logistic regression analysis was performed to determine the relationship between sociodemographic variables and supplement use. A total of 78 % of the participants reported using at least one dietary supplement in the first trimester. Folic acid supplement use was reported by 74 %, vitamin D supplement use by 43 % and n-3 supplement use by <5 %. Use of any type of supplement in early pregnancy was related to gestational age, parity, birthplace, education and employment. Folic acid supplement use was related to gestational age, parity, birthplace, income, education and employment. Vitamin D supplement use was related to gestational age, birthplace and education. In conclusion, in the first trimester of pregnancy, folic acid supplements were used by three in four women, while vitamin D supplements were used by less than half of the women. The results of this study show a socioeconomic disparity between supplement users and non-users which may have a negative impact on the health of future generations.
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| 12. |
- Bärebring, Linnea, et al.
(författare)
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Trajectory of vitamin D status during pregnancy in relation to neonatal birth size and fetal survival: a prospective cohort study
- 2018
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Ingår i: BMC Pregnancy and Childbirth. - : Springer Science and Business Media LLC. - 1471-2393. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Background: We investigated the associations between vitamin D status in early and late pregnancy with neonatal small for gestational age (SGA), low birth weight (LBW) and preterm delivery. Furthermore, associations between vitamin D status and pregnancy loss were studied. Methods: Serum 25-hydroxyvitamin D (25OHD) was sampled in gestational week <= 16 (trimester 1 (T1), N = 2046) and > 31 (trimester 3 (T3), N = 1816) and analysed using liquid chromatography tandem mass spectrometry. Pregnant women were recruited at antenatal clinics in south-west Sweden at latitude 57-58 degrees N. Gestational and neonatal data were retrieved from medical records. Multiple gestations and terminated pregnancies were excluded from the analyses. SGA was defined as weight and/or length at birth < 2 SD of the population mean and LBW as < 2500 g. Preterm delivery was defined as delivery < 37 + 0 gestational weeks and pregnancy loss as spontaneous abortion or intrauterine fetal death. Associations between neonatal outcomes and 25OHD at T1, T3 and change in 25OHD (T3-T1) were studied using logistic regression. Results: T1 25OHD was negatively associated with pregnancy loss and 1 nmol/L increase in 25OHD was associated with 1% lower odds of pregnancy loss (OR 0.99, p = 0.046). T3 25OHD >= 100 nmol/L (equal to 40 ng/ml) was associated with lower odds of SGA (OR 0.3, p = 0.031) and LBW (OR 0.2, p = 0.046), compared to vitamin D deficiency (25OHD < 30 nmol/L, or 12 ng/ml). Women with a >= 30 nmol/L increment in 25OHD from T1 to T3 had the lowest odds of SGA, LBW and preterm delivery. Conclusions: Vitamin D deficiency in late pregnancy was associated with higher odds of SGA and LBW. Lower 25OHD in early pregnancy was only associated with pregnancy loss. Vitamin D status trajectory from early to late pregnancy was inversely associated with SGA, LBW and preterm delivery with the lowest odds among women with the highest increment in 25OHD. Thus, both higher vitamin D status in late pregnancy and gestational vitamin D status trajectory can be suspected to play a role in healthy pregnancy.
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| 13. |
- Bärebring, Linnea, et al.
(författare)
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Vitamin D Status during Pregnancy in a Multi-Ethnic Population-Representative Swedish Cohort.
- 2016
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- There is currently little information on changes in vitamin D status during pregnancy and its predictors. The aim was to study the determinants of change in vitamin D status during pregnancy and of vitamin D deficiency (<30 nmol/L) in early pregnancy. Blood was drawn in the first (T1) and third trimester (T3). Serum 25-hydroxyvitamin D (25(OH)D) (N = 1985) was analysed by liquid chromatography tandem-mass spectrometry. Season-corrected 25(OH)D was calculated by fitting cosine functions to the data. Mean (standard deviation) 25(OH)D was 64.5(24.5) nmol/L at T1 and 74.6(34.4) at T3. Mean age was 31.3(4.9) years, mean body mass index (BMI) was 24.5(4.2) kg/m² and 74% of the women were born in Sweden. Vitamin D deficiency was common among women born in Africa (51%) and Asia (46%) and prevalent in 10% of the whole cohort. Determinants of vitamin D deficiency at T1 were of non-North European origin, and had less sun exposure, lower vitamin D intake and lower age. Season-corrected 25(OH)D increased by 11(23) nmol/L from T1 to T3. The determinants of season-corrected change in 25(OH)D were origin, sun-seeking behaviour, clothing style, dietary vitamin D intake, vitamin D supplementation and recent travel <35° N. In conclusion, season-corrected 25(OH)D concentration increased during pregnancy and depended partly on lifestyle factors. The overall prevalence of vitamin D deficiency was low but common among women born in Africa and Asia. Among them, the determinants of both vitamin D deficiency and change in season-corrected vitamin D status were fewer, indicating a smaller effect of sun exposure.
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| 14. |
- Duchemin, Sandrine, et al.
(författare)
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Identification of QTL on chromosome 18 associated with non-coagulating milk in Swedish Red cows
- 2016
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Ingår i: Frontiers in Genetics. - : Frontiers Media SA. - 1664-8021. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Non-coagulating (NC) milk, defined as milk not coagulating within 40 min after rennet-addition, can have a negative influence on cheese production. Its prevalence is estimated at 18% in the Swedish Red (SR) cow population. Our study aimed at identifying genomic regions and causal variants associated with NC milk in SR cows, by doing a GWAS using 777k SNP genotypes and using imputed sequences to fine map the most promising genomic region. Phenotypes were available from 382 SR cows belonging to 21 herds in the south of Sweden, from which individual morning milk was sampled. NC milk was treated as a binary trait, receiving a score of one in case of non-coagulation within 40 min. For all 382 SR cows, 777k SNP genotypes were available as well as the combined genotypes of the genetic variants of as1-β-κ-caseins. In addition, whole-genome sequences from the 1000 Bull Genome Consortium (Run 3) were available for 429 animals of 15 different breeds. From these sequences, 33 sequences belonged to SR and Finish Ayrshire bulls with a large impact in the SR cow population. Single-marker analyses were run in ASReml using an animal model. After fitting the casein loci, 14 associations at -Log10(P-value) > 6 identified a promising region located on BTA18. We imputed sequences to the 382 genotyped SR cows using Beagle 4 for half of BTA18, and ran a region-wide association study with imputed sequences. In a seven mega base-pairs region on BTA18, our strongest association with NC milk explained almost 34% of the genetic variation in NC milk. Since it is possible that multiple QTL are in strong LD in this region, 59 haplotypes were built, genetically differentiated by means of a phylogenetic tree, and tested in phenotype-genotype association studies. Haplotype analyses support the existence of one QTL underlying NC milk in SR cows. A candidate gene of interest is the VPS35 gene, for which one of our strongest association is an intron SNP in this gene. The VPS35 gene belongs to the mammary gene sets of pre-parturient and of lactating cows.
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| 15. |
- Edén, Jonas, et al.
(författare)
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The influence of serum phase on the whipping time of unhomogenised cream
- 2015
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946. ; 49, s. 56-61
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate how the properties of the serum phase, including ionic strength, protein content and specific milk salts, influence the whipping time of unhomogenised cream. This study showed that decreasing the protein content of the serum phase in cream resulted in shorter whipping time. However, addition of UF permeate to both deproteinated and proteinated creams indicated that other components than the protein fraction also influence whipping time of unhomogenised cream. Increasing the ionic strength by addition of NaCl, KCl and CaCl2 decreased whipping time, with the largest effect being found for CaCl2. A further increase in ionic strength by addition of NaCl and KCl resulted in an unfavourable effect on whipping time, whereas a pronounced effect, with shorter whipping times, was found for addition of CaCl2. (C) 2015 Elsevier Ltd. All rights reserved.
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| 16. |
- Glantz, Maria, et al.
(författare)
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Bovine chromosomal regions affecting rheological traits in acid-induced skim milk gels.
- 2015
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 98:2, s. 1273-1285
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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.
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| 17. |
- Glantz, Maria, et al.
(författare)
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Effect of polymorphisms in the leptin, leptin receptor and acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) genes and genetic polymorphism of milk proteins on bovine milk composition.
- 2012
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Ingår i: Journal of Dairy Research. - 0022-0299. ; 79:1, s. 110-118
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Tidskriftsartikel (refereegranskat)abstract
- The relations between cow genetics and milk composition have gained a lot of attention during the past years, however, generally only a few compositional traits have been examined. The aim of this study was to determine if polymorphisms in the leptin (LEP), leptin receptor (LEPR) and acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) genes as well as genetic polymorphism of β-casein (β-CN), κ-CN and β-lactoglobulin (β-LG) impact several bovine milk composition traits. Individual milk samples from the Swedish Red and Swedish Holstein breeds were analyzed for components in the protein, lipid, carbohydrate and mineral profiles. Cow alleles were determined on the following SNP: A1457G, A252T, A59V and C963T on the LEP gene, T945M on the LEPR gene and Nt984+8(A-G) on the DGAT1 gene. Additionally, genetic variants of β-CN, κ-CN and β-LG were determined. For both the breeds, the same tendency of minor allele frequency was found for all SNPs and protein genes, except on LEPA1457G and LEPC963T. This study indicated significant (P<0·05) associations between the studied SNPs and several compositional parameters. Protein content was influenced by LEPA1457G (G>A) and LEPC963T (T>C), whereas total Ca, ionic Ca concentration and milk pH were affected by LEPA1457G, LEPA59V, LEPC963T and LEPRT945M. However, yields of milk, protein, CN, lactose, total Ca and P were mainly affected by β-CN (A2>A1) and κ-CN (A>B>E). β-LG was mainly associated with whey protein yield and ionic Ca concentration (A>B). Thus, this study shows possibilities of using these polymorphisms as markers within genetic selection programs to improve and adjust several compositional parameters.
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| 18. |
- Glantz, Maria, et al.
(författare)
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Effect of polymorphisms in the leptin, leptin receptor, and acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) genes and genetic polymorphism of milk proteins on cheese characteristics.
- 2011
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 94:7, s. 3295-3304
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Tidskriftsartikel (refereegranskat)abstract
- Cheese production has increased worldwide during the last decade and is expected to increase within the coming decade as well. Despite this, the relations between cow genetics and cheese characteristics are not fully known. The aim of this study was to determine if polymorphisms in the leptin (LEP), leptin receptor (LEPR), and acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) genes as well as genetic variants of β-casein (β-CN), κ-CN, and β-lactoglobulin (β-LG) affect technological properties important for cheese production and, hence, could act as genetic makers for cheese quality. Individual milk samples from the Swedish Red and the Swedish Holstein breeds were analyzed for sizes of CN micelles and fat globules as well as rennet-induced gel strength, gelation time, and yield stress. Model cheeses were produced to study yield, hardness, and pH of the cheeses. The A1457G, A252T, A59V, and C963T single nucleotide polymorphisms (SNP) were analyzed on the LEP gene, the T945M SNP on the LEPR gene, and the Nt984+8(A-G) SNP on the DGAT1 gene. In addition, genetic variants of β-CN, κ-CN, and β-LG were determined. The results indicate that technological properties were influenced by the LEPR(T945M) polymorphism, which had an association with gel strength, yield stress, and cheese hardness (T > C). However, also LEP(A252T) was shown to affect gel strength (T > A), whereas the LEP(A59V) had an effect on fat globule size (T > C). For the milk protein genes, favorable effects were found for the A and B variants of β-LG and κ-CN, respectively, on gel strength, gelation time, and yield stress. In addition, the B variant of κ-CN was shown to be associated with smaller CN micelles than the A variant. Thus, the results demonstrate potential genetic markers for cheese characteristics. However, milk composition traits also affected the obtained results, thus making it necessary to thoroughly assess the different aspects regarding the influence of gene effects on cheese characteristics before directly selecting for certain alleles or genetic variants to improve the processing and quality of cheese.
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| 19. |
- Glantz, Maria, et al.
(författare)
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Effects of animal selection on milk composition and processability.
- 2009
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 92:9, s. 4589-4603
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Tidskriftsartikel (refereegranskat)abstract
- One goal of animal breeding is to increase the economic output through increased production, improved milk quality, and cow health. The objective of this study was to evaluate genetic progress in relation to milk composition, processability, and yield as a correlated response to selection for the Swedish breeding objective. Dairy cows with high genetic merit, classified as elite dairy cows, of the Swedish Red and Swedish Holstein breeds were used. Milk samples were collected on the farm level in winter and summer from a research herd at Nötcenter Viken, a bovine research farm in Sweden. Comparisons were made with milk from a Swedish Red herd, a Swedish Holstein herd, and a Swedish dairy processor in the same geographical area. Protein, lipid, and carbohydrate profiles as well as minerals were analyzed, and technological properties, including rennet-induced gelation characteristics, lipid oxidation, total antioxidant capacity, and fat globule size, were determined. Higher yields were found for elite cows for components of the protein, lipid, and carbohydrate profiles as well as for minerals, implying genetic progress in relation to milk yield; however, the content of some milk components (e.g., lipid and whey protein contents) had decreased on average. Milk from the elite cows had good gelation characteristics, but was more susceptible to lipid autooxidation and had a lower total antioxidant capacity. These results demonstrate that milk composition and processing characteristics could be used to adjust breeding practices to optimize the quality and stability of milk and dairy products.
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| 20. |
- Glantz, Maria, et al.
(författare)
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Genomic selection in relation to bovine milk composition and processability.
- 2012
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Ingår i: Journal of Dairy Research. - 0022-0299. ; 79:1, s. 53-59
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Tidskriftsartikel (refereegranskat)abstract
- Genomic selection is a new technology in which selection decisions are based on direct genomic values (DGVs) or genomic enhanced breeding values (GEBVs). The objective of this study was to evaluate the relations between DGVs and several milk traits important for both the nutritional value and processability of milk. This is a new approach and can be used to increase the knowledge on how genomic selection can be used in practice. Morning milk samples from Swedish Holstein cows were analyzed for milk composition and technological properties. DGVs were received for each cow for milk, protein and fat yield, milk index, udder health, Nordic total merit and a quota was calculated between fat and milk yield as well as protein and milk yield. The results show that linear correlations exist (P<0·10) between the studied DGVs and contents and yields of parameters in the protein (P=0·002-0·097), fat (P=0·024-0·055) and mineral profiles (P=0·001-0·099) as well as for cheese characteristics (P=0·004-0·065), thus making it possible to obtain detailed information on milk traits that are not registered in the milk recording scheme. Hence, genomic selection will be an efficient tool for breeding and dairy industry to select cows early in life for targeted milk production.
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| 21. |
- Glantz, Maria, et al.
(författare)
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Importance of casein micelle size and milk composition for milk gelation.
- 2010
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 93:4, s. 1444-1451
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Tidskriftsartikel (refereegranskat)abstract
- The economic output of the dairy industry is to a great extent dependent on the processing of milk into other milk-based products such as cheese. The yield and quality of cheese are dependent on both the composition and technological properties of milk. The objective of this study was to evaluate the importance and effects of casein (CN) micelle size and milk composition on milk gelation characteristics in order to evaluate the possibilities for enhancing gelation properties through breeding. Milk was collected on 4 sampling occasions at the farm level in winter and summer from dairy cows with high genetic merit, classified as elite dairy cows, of the Swedish Red and Swedish Holstein breeds. Comparisons were made with milk from a Swedish Red herd, a Swedish Holstein herd, and a Swedish dairy processor. Properties of CN micelles, such as their native and rennet-induced CN micelle size and their zeta-potential, were analyzed by photon correlation spectroscopy, and rennet-induced gelation characteristics, including gel strength, gelation time, and frequency sweeps, were determined. Milk parameters of the protein, lipid, and carbohydrate profiles as well as minerals were used to obtain correlations with native CN micelle size and gelation characteristics. Milk pH and protein, CN, and lactose contents were found to affect milk gelation. Smaller native CN micelles were shown to form stronger gels when poorly coagulating milk was excluded from the correlation analysis. In addition, milk pH correlated positively, whereas Mg and K correlated negatively with native CN micellar size. The milk from the elite dairy cows was shown to have good gelation characteristics. Furthermore, genetic progress in relation to CN micelle size was found for these cows as a correlated response to selection for the Swedish breeding objective if optimizing for milk gelation characteristics. The results indicate that selection for smaller native CN micelles and lower milk pH through breeding would enhance gelation properties and may thus improve the initial step in the processing of cheese.
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| 22. |
- Glantz, Maria
(författare)
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Milk Genomics – Impact of Genetic Polymorphism on Bovine Milk Composition and Processability
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Milk genomics is a new area of research that explores the relations between cow genetics and milk characteristics. Identifying the genes controlling compositional and technological traits of milk will give opportunities to select cows for targeted milk production. In this thesis, the impact of different genetic approaches, i.e. quantitative genetic evaluation, single gene effects and genomic selection, on numerous compositional traits and technological properties of milk have been studied. The cows used were elite dairy cows of the Swedish Holstein and Swedish Red breeds with high genetic merit, reflecting the future Swedish cow population. The elite dairy cows were shown to have genetic progress in relation to yields of milk and milk components that are to a great extent contributing to the Nordic total merit of the Swedish breeding objective, whereas the contents of some milk components, e.g. lipid and whey protein contents, had decreased on average. Milk from the elite cows had good rennet-induced gelation properties, but was more susceptible to lipid autooxidation. These findings show clearly that breeding program influences milk characteristics considerably, offering opportunities to alter milk quality through breeding. Selecting for smaller casein micelles and lower milk pH through breeding would enhance gelation properties and may thus improve the initial step in the processing of cheese. Furthermore, it was shown that the majority of the casein micelles have a spherical shape, but a low concentration of larger and elongated aggregates exists, which can be expected to have a large impact on technological properties during renneting of milk. Polymorphisms in the leptin, leptin receptor, ß-casein, κ-casein and ß-lactoglobulin genes were shown to be associated with milk composition traits and cheese characteristics, thus indicating possibilities of using these polymorphisms as markers within genetic selection programs to improve and adjust several parameters and properties. Using genomic selection, relations between direct genomic values for traditional production traits and novel milk traits were found. This shows opportunities of indirect selection of milk composition traits and technological properties important for cheese production that are not registered in the milk recording scheme. In conclusion, this thesis has shown possibilities of changing the quality and functionality of milk through selective breeding. The Swedish breeding objective is today and was previously selecting for milk composition by analyzing the contents and yields of lipids and proteins. This study goes beyond this traditional breeding strategy by analyzing compositional traits and technological properties in detail and has thus contributed to a deeper knowledge of milk quality. This gives opportunities to meet new demands on milk, which certainly will increase the economic output of both the breeding and dairy industries.
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| 23. |
- Glantz, Maria, et al.
(författare)
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Revealing the size, conformation, and shape of casein micelles and aggregates with asymmetrical flow field-flow fractionation and multiangle light scattering.
- 2010
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 26:15, s. 12585-12591
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Tidskriftsartikel (refereegranskat)abstract
- Casein (CN) micelles are naturally occurring colloidal protein aggregates present in a dispersed state in milk. In this paper we aim to obtain a detailed description of physicochemical properties of CN micelles over the entire size distribution using asymmetrical flow field-flow fractionation (AsFlFFF) connected to multiangle light scattering (MALS) and refractive index (RI) detection. Conclusions are drawn on the colloidal level regarding shape and conformation by comparison with models of colloidal particles. By using AsFlFFF-MALS-RI, it is concluded that the CN micelles are highly polydisperse with an average rms radius and hydrodynamic radius of 177 and 116 nm, respectively. The results show that the majority of CN micelles have a spherical shape, whereas a low concentration exists of larger and elongated aggregates. By comparison with models of aggregates of colloidal particles, the aggregates are shown to be anisotropic, e.g., aggregating linearly (threadlike) or in a sheet, rather than forming randomly spherical clusters. The results show that the characterization of colloidal dispersions with AsFlFFF-MALS-RI and the comparison with theoretical models are of a general character and, thus, of fundamental importance for colloidal dispersions.
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| 24. |
- Gregersen, V R, et al.
(författare)
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Bovine chromosomal regions affecting rheological traits in rennet-induced skim milk gels.
- 2015
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 98:2, s. 1261-1272
-
Tidskriftsartikel (refereegranskat)abstract
- Optimizing cheese yield and quality is of central importance to cheese manufacturing. The yield is associated with the time it takes before the gel has an optimal consistency for further processing, and it is well known that gel formation differs between individual milk samples. By identifying genomic regions affecting traits related to rennet-induced gelation, the aim of this study was to identify potential candidate genes affecting these traits. Hence, rennet-induced gelation, including rennet coagulation time, gel strength, and yield stress, was measured in skim milk samples collected from 379 animals of the Swedish Red breed using low-amplitude oscillation measurements. All animals had genotypes for almost 621,000 segregating single nucleotide polymorphisms (SNP), identified using the Bovine HD SNPChip (Illumina Inc., San Diego, CA). The genome was scanned for associations, haplotypes based on SNP sets comprising highly associated SNP were inferred, and the effects of the 2 most common haplotypes within each region were analyzed using mixed models. Even though the number of animals was relatively small, a total of 21 regions were identified, with 4 regions showing association with more than one trait. A major quantitative trait locus for all traits was identified around the casein cluster explaining between 9.3 to 15.2% of the phenotypic variation of the different traits. In addition, 3 other possible candidate genes were identified; that is, UDP-n-acetyl-α-d-galactosamine:polypeptide n-acetylgalactosaminyl-transferase 1 (GALNT1), playing a role in O-glycosylation of κ-casein, and 2 cathepsins, CTSZ and CTSC, possibly involved in proteolysis of milk proteins. We have shown that other genes than the casein genes themselves may be involved in the regulation of gelation traits. However, additional analysis is needed to confirm these results. To our knowledge, this is the first study identifying quantitative trait loci affecting rennet-induced gelation of skim milk through a high-density genome-wide association study.
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| 25. |
- Gustavsson, Frida, et al.
(författare)
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Effects of breed and casein genetic variants on protein profile in milk from Swedish Red, Danish Holstein, and Danish Jersey cows.
- 2014
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 97:6, s. 3866-3877
-
Tidskriftsartikel (refereegranskat)abstract
- In selecting cows for higher milk yields and milk quality, it is important to understand how these traits are affected by the bovine genome. The major milk proteins exhibit genetic polymorphism and these genetic variants can serve as markers for milk composition, milk production traits, and technological properties of milk. The aim of this study was to investigate the relationships between casein (CN) genetic variants and detailed protein composition in Swedish and Danish dairy milk. Milk and DNA samples were collected from approximately 400 individual cows each of 3 Scandinavian dairy breeds: Swedish Red (SR), Danish Holstein (DH), and Danish Jersey (DJ). The protein profile with relative concentrations of α-lactalbumin, β-lactoglobulin, and αS1-, αS2-, κ-, and β-CN was determined for each milk sample using capillary zone electrophoresis. The genetic variants of the αS1- (CSN1S1), β- (CSN2), and κ-CN (CSN3) genes for each cow were determined using TaqMan SNP genotyping assays (Applied Biosystems, Foster City, CA). Univariate statistical models were used to evaluate the effects of composite genetic variants, αS1-β-κ-CN, on the protein profile. The 3 studied Scandinavian breeds differed from each other regarding CN genotypes, with DH and SR having similar genotype frequencies, whereas the genotype frequencies in DJ differed from the other 2 breeds. The similarities in genotype frequencies of SR and DH and differences compared with DJ were also seen in milk production traits, gross milk composition, and protein profile. Frequencies of the most common composite αS1-β-κ-CN genotype BB/A(2)A(2)/AA were 30% in DH and 15% in SR, and cows that had this genotype gave milk with lower relative concentrations of κ- and β-CN and higher relative concentrations of αS-CN, than the majority of the other composite genotypes in SR and DH. The effect of composite genotypes on relative concentrations of the milk proteins was not as pronounced in DJ. The present work suggests that a higher frequency of BB/A(1)A(2)/AB, together with a decrease in BB/A(2)A(2)/AA, could have positive effects on DH and SR milk regarding, for example, the processing of cheese.
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| 26. |
- Gustavsson, Frida, et al.
(författare)
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Factors influencing chymosin-induced gelation of milk from individual dairy cows: Major effects of casein micelle size and calcium
- 2014
-
Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946 .- 1879-0143. ; 39:1, s. 201-208
-
Tidskriftsartikel (refereegranskat)abstract
- Optimisation of cheese yield is crucial for cheese production; a previous study showed large variations in chymosin-induced coagulation in milk from the second most common Swedish dairy breed, Swedish Red. In the present study, the effect of gross composition, protein composition, total and ionic calcium content, phosphorous content and casein micelle size on chymosin-induced gelation was determined in milk from 98 Swedish Red cows. The study showed that protein content and total calcium content, ionic calcium concentration and casein micelle size were the most important factors explaining the variation of gelation properties in this sample set. Non-coagulating milk was suggested to have lower ionic and total calcium content as well as lower relative concentrations of beta-lactoglobulin than coagulating milk. The lower total calcium content in non-coagulating milk poses a problem as the difference was, theoretically, four times larger than the amount of calcium that is normally added in cheese processing. (C) 2014 Elsevier Ltd. All rights reserved.
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| 27. |
- Gustavsson, Frida, et al.
(författare)
-
Genetic parameters for rennet- and acid-induced coagulation properties in milk from Swedish Red dairy cows.
- 2014
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 97:8, s. 5219-5229
-
Tidskriftsartikel (refereegranskat)abstract
- Milk coagulation is an important processing trait, being the basis for production of both cheese and fermented products. There is interest in including technological properties of these products in the breeding goal for dairy cattle. The aim of the present study was therefore to estimate genetic parameters for milk coagulation properties, including both rennet- and acid-induced coagulation, in Swedish Red dairy cattle using genomic relationships. Morning milk samples and blood samples were collected from 395 Swedish Red cows that were selected to be as genetically unrelated as possible. Using a rheometer, milk samples were analyzed for rennet- and acid-induced coagulation properties, including gel strength (G'), coagulation time, and yield stress (YS). In addition to the technological traits, milk composition was analyzed. A binary trait was created to reflect that milk samples that had not coagulated 40 min after rennet addition were considered noncoagulating milk. The cows were genotyped by using the Illumina BovineHD BeadChip (Illumina Inc., San Diego, CA). Almost 600,000 markers remained after quality control and were used to construct a matrix of genomic relationships among the cows. Multivariate models including fixed effects of herd, lactation stage, and parity were fitted using the ASReml software to obtain estimates of heritabilities and genetic and phenotypic correlations. Heritability estimates (h(2)) for G' and YS in rennet and acid gels were found to be high (h(2) = 0.38-0.62) and the genetic correlations between rennet-induced and acid-induced coagulation properties were weak but favorable, with the exception of YSrennet with G'acid and YSacid, both of which were strong. The high heritability (h(2) = 0.45) for milk coagulating ability expressed as a binary trait suggests that noncoagulation could be eliminated through breeding. Additionally, the results indicated that the current breeding objective could increase the frequency of noncoagulating milk and lead to deterioration of acid-induced coagulation through unfavorable genetic associations with protein content (0.38) and milk yield (-0.61 to -0.71), respectively. The outcome of this study suggests that by including more detailed compositional traits genetically associated with milk coagulation or by including milk coagulation properties directly within the breeding goal, it appears possible to breed cows that produce milk better suited for production of cheese and fermented products.
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| 28. |
- Gustavsson, Frida, et al.
(författare)
-
Impact of genetic variants of milk proteins on chymosin-induced gelation properties of milk from individual cows of Swedish Red dairy cattle
- 2014
-
Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946 .- 1879-0143. ; 39:1, s. 102-107
-
Tidskriftsartikel (refereegranskat)abstract
- Chymosin-induced gelation properties of the milk of around 400 Swedish Red dairy cows was investigated with the aim of identifying genetic protein variants that influence chymosin-induced gelation for optimisation of cheese milk through breeding practices. The variation in chymosin-induced gelation properties was shown to be large in the milk of Swedish Red and there was a high frequency of cows producing non-coagulating milk, 18%. The present study showed that the common composite beta-kappa-casein genotypes A(1)A(2)/AE and A(2)A(2)/AA were associated with both poor gelation properties and non-coagulation in the milk of Swedish Red. The present study suggests that if the frequencies of composite genotypes A(1)A(2)/AE and A(2)A(2)/AA were decreased in the Swedish Red population in favour for A(1)A(1)/AA and A(1)A(1)/AE, this could have a positive effect on the rennetability of the milk. (C) 2014 Elsevier Ltd. All rights reserved.
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| 29. |
- Lalwani, Shruti, et al.
(författare)
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A pilot scale study on the effects of various temperature and time conditions on milk quality using direct and indirect heating systems
- 2024
-
Ingår i: International Dairy Journal. - 0958-6946. ; 155
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Tidskriftsartikel (refereegranskat)abstract
- Effects of various heating temperatures (124, 129, 134, 140 or 143 °C) and holding times (1 and 4 s) on milk quality using direct and indirect heating systems at pilot scale were investigated. Vitamin degradation was observed for both direct and indirect heating and the degradation increased with increasing temperature and holding time, however, no difference could be seen between heating systems. Slight increase in pH and decrease in ionic calcium for direct heating occurred. An increase in fat globule size and aggregate formation were noted for direct heating with more pronounced effects with increasing temperature. Physical stability of milk was unaffected on day of production; however, after 28 days of storage instability was more apparent for indirect heating. No effect of heating system was observed on colour. This suggests that heating may influence milk quality, however, no clear differences between direct and indirect heating were observed for the quality parameters investigated.
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| 30. |
- Lalwani, Shruti, et al.
(författare)
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Changes in nutritional and technological properties of heat-treated milk and cream at dairy production scale during storage
- 2024
-
Ingår i: International Dairy Journal. - 0958-6946. ; 154
-
Tidskriftsartikel (refereegranskat)abstract
- Changes in nutritional and technological properties during storage of milk and cream subjected to different heat treatments at dairy production scale (high-temperature-short-time pasteurisation, extended shelf-life treatment and ultra-high temperature treatment) were investigated. Results indicate a decrease in pH with longer storage times, whereas no changes in ionic calcium concentration occurred during shorter storage. Vitamin losses ranged from 1 to 22% for different heat treatments and more pronounced effects of vitamin degradation was observed with more intense heat treatment and longer storage times. Vitamin B12 concentration tended to decrease more over time than vitamins B1, B2 and E and more losses in vitamin concentration were found after storage than after heat treatment. Significant effects on physical stability and colour changes in milk and cream were observed during prolonged storage. This suggests that larger changes in nutritional and technological quality of heat-treated milk and cream at dairy production scale occur during longer storage times.
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| 31. |
- Lalwani, Shruti, et al.
(författare)
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Exploring predictive kinetic modelling of thermal degradation from laboratory to production scale – A case study on three vitamins in milk
- 2024
-
Ingår i: Food and Bioproducts Processing. - 0960-3085. ; 146, s. 69-76
-
Tidskriftsartikel (refereegranskat)abstract
- Kinetic thermal degradation models are vital components for optimization of food and bioproducts processing. Typically, models are fitted to laboratory-scale experiments where vials are heated and held. However, these conditions are highly dissimilar from the thermal processes experienced in industrial production. Whereas fitting kinetic data to industrial-scale production is often impossible due to cost and flexibility issues, this discrepancy between what is typically measured and what the models are intended for could be of concern. This study presents a case study where traditional laboratory experiments are fitted to vitamin degradation kinetic models in milk (vitamins B1, B2, and E). The best-fitted kinetic models are then validated using five, carefully controlled industrial-scale dairy processes. Results show that predictions are surprisingly close to the validation data (mean relative percentual deviation is −1.1 %–+3 % depending on vitamin), given the substantial difference between the laboratory and production scale setup. This offers empirical support for the conventional method of fitting kinetic parameters through simplified laboratory experiments to predict vitamin degradation during industrial scale processing of foods and bioproducts.
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| 32. |
- Lalwani, Shruti, et al.
(författare)
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Impact of thermal processing on micronutrients and physical stability of milk and cream at dairy production scale
- 2024
-
Ingår i: International Dairy Journal. - 0958-6946. ; 153
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Tidskriftsartikel (refereegranskat)abstract
- Micronutrients and physical stability of milk and cream were evaluated for different heat treatments at dairy production scale (HTST pasteurisation, high pasteurisation, ESL indirect and UHT direct and indirect). Changes caused due to heat treatments for macro and micro components (vitamins and minerals) as well as physical stability were investigated. Results show limited losses in macro components and total mineral concentrations for milk and cream after the studied heat treatments. Significant decrease in concentrations of vitamins B1, B2 and B12 and ionic calcium in milk was observed after high pasteurisation, whereas limited losses were observed after ESL and UHT processing. Casein micelle size in milk increased, however, no effect on physical stability was observed between heat treatments. This work shows that heating technologies at industrial dairy production scale investigated were mild and have low effects on micronutrients and physical stability of milk and cream.
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| 33. |
- Lalwani, Shruti, et al.
(författare)
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The effect of free convection on apparent vitamin degradation kinetics
- 2021
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Ingår i: Food and Bioproducts Processing. - : Elsevier BV. - 0960-3085. ; 130, s. 182-194
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Tidskriftsartikel (refereegranskat)abstract
- Experimentally determined vitamin degradation kinetic parameters are vital input for process optimization, e.g., of nutrient rich beverages such as milk and fruit juices. The standard method of obtaining these parameters is to subject a test-tube of the nutrient (in its food matrix) to a water bath at elevated temperatures and measure remaining concentration as a function of time. It is well known that accurate kinetic fitting requires measuring the temperature inside the test tube as a function of time (due to lag it is not identical to the water-bath temperature), and this is included in contemporary studies. However, the importance of axial temperature gradients for valid kinetic parameter estimations has not been discussed to the same extent. This contribution combines experiments and physical modelling to show how an axial temperature gradient evolves in a test tube (R = 13 mm, Z = 75 mm), due to free convection currents (T∞ – T0 = 57–71 °C). Consequently, the test tube temperature is not uniform in such an experiment. Thus, the positioning of the thermocouple in a test-tube-in-water bath experiment is essential for ensuring a valid estimation of the kinetic parameters. Simulations suggest that positioning it half-way between top and bottom is a suitable best practice.
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| 34. |
- Nilsson, Kajsa, et al.
(författare)
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An investigation of the enzymatic cleavage of κ-casein in non-coagulating milk
- 2020
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946. ; 109
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Tidskriftsartikel (refereegranskat)abstract
- Non-coagulating milk is unwanted in cheese production because it impairs chymosin-induced coagulation properties in bulk milk. Milk samples were analysed to investigate the coagulation process in non-coagulating milk for comparison with milk samples that have a high coagulation ability. This was done by measuring two peptides after chymosin cleavage, namely para-κ-casein and caseinomacropeptide, in all the milk samples using capillary electrophoresis. The results showed that cleavage of κ-casein into para-κ-casein and caseinomacropeptide occurred in both coagulation groups, suggesting that the aggregation stage is the cause of non-coagulating milk. Non-coagulating milk had lower content of para-κ-casein after chymosin addition compared with coagulating milk, which might be the result of a lower content of available κ-casein. Furthermore, this study indicates that there are different mechanisms that explain good coagulation ability and lack of coagulation ability of milk. The results can be useful in understanding the potential chemical mechanisms behind non-coagulating milk.
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| 35. |
- Nilsson, Kajsa, et al.
(författare)
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Characterisation of non-coagulating milk and effects of milk composition and physical properties on rennet-induced coagulation in Swedish Red Dairy Cattle
- 2019
-
Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946 .- 1879-0143. ; 95, s. 50-57
-
Tidskriftsartikel (refereegranskat)abstract
- Non-coagulating milk is a serious problem in the cheese industry, since it decreases cheese yield, resulting in decreased economic output. This study evaluated rennet-induced coagulation properties and composition of milk from individual Swedish Red Dairy Cattle. Milk samples from 679 individual cows were rheologically evaluated, of which 18.1% of the cows produced non-coagulating milk and 18.9% produced poor-coagulating milk. This resulted in 37% of the milk samples being non-optimal in cheese production, which is an alarmingly high figure. A comparison between non-coagulating and coagulating milk showed a significantly lower calcium content and less free Ca 2+ in non-coagulating milk. The results provide more information about non- and poor-coagulating milk and will be further used to understand the genetic background of non-coagulating milk and breed against this undesired milk property.
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| 36. |
- Petrov Fieril, Karolina, et al.
(författare)
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Experiences of exercise during pregnancy among women who perform regular resistance training: A qualitative study
- 2014
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Ingår i: Physical Therapy. - : Oxford University Press (OUP). - 0031-9023 .- 1538-6724. ; 94:8, s. 1135-1143
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Tidskriftsartikel (refereegranskat)abstract
- Background. Women who are pregnant and healthy are recommended to do 30 minutes or more of light to moderate exercise a day on most, if not all, days of the week. However, only 1 of 6 pregnant women in the United States and northern Europe follows these recommendations. Little attention has been given to the experience of exercise in pregnancy. Objectives. The aim of the study was to describe experiences of exercise during pregnancy among women who performed regular resistance training. Design. This was a qualitative, inductive content analysis study. Methods. Seventeen pregnant women who exercised on a regular basis participated in individual semistructured, face-to-face interviews that were recorded, transcribed, coded, and condensed into subcategories and categories. Results. Four categories emerged (subcategories within parentheses): (1) positive impact on body and mind (reduced pregnancy-related problems, increased self-confidence and sense of control, immediate positive feedback, and effects on lifestyle and quality of life); (2) expected benefits and facilitators (knowledge of health benefits, part of one's lifestyle, preventing pregnancy-related problems, social support, staying in good shape, and healthy living with regard to the fetus); (3) new exercise barriers (physical limitations, taking care not to harm oneself or the fetus, uncertainty or lack of knowledge, sense of exclusion at the fitness center, lack of understanding on the part of others, and the pregnancy itself provided an easy excuse); and (4) overcoming exercise barriers (lowering the intensity of exercise, modifying the type of exercise, changing exercise goals, and being extra attentive during exercise). Conclusion. Pregnant women strived to exercise if the exercise facilitators outweighed the barriers. As the study described facilitators, barriers, and strategies for how to overcome exercise barriers, the results can be useful in exercise promotion in healthy pregnancy. © 2014 American Physical Therapy Association.
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| 37. |
- Poulsen, Nina A, et al.
(författare)
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Comparison of milk protein composition and rennet coagulation properties in native Swedish dairy cow breeds and high-yielding Swedish Red cows
- 2017
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302. ; 100:11, s. 8722-8734
-
Tidskriftsartikel (refereegranskat)abstract
- Recent studies have reported a very high frequency of noncoagulating milk in Swedish Red cows. The underlying factors are not fully understood. In this study, we explored rennet-induced coagulation properties and relative protein profiles in milk from native Swedish Mountain and Swedish Red Polled cows and compared them with a subset of noncoagulating (NC) and well-coagulating (WC) milk samples from modern Swedish Red cows. The native breeds displayed a very low prevalence of NC milk and superior milk coagulation properties compared with Swedish Red cows. The predominant variants in both native breeds were αS1-casein (αS1-CN) B, β-CN A2 and β-lactoglobulin (β-LG) B. For κ-CN, the B variant was predominant in the Swedish Mountain cows, whereas the A variant was the most frequent in the Swedish Red Polled. The native breeds displayed similar protein composition, but varied in content of αS1-CN with 9 phosphorylated serines (9P) form. Within the Swedish Mountain cows, we observed a strong inverse correlation between the relative concentration of κ-CN and micelle size and a positive correlation between ionic calcium and gel firmness. For comparison, we investigated a subset of 29 NC and 28 WC milk samples, representing the extremes with regard to coagulation properties based on an initial screening of 395 Swedish Red cows. In Swedish Red, NC milk properties were found to be related to higher frequencies of β-CN A2, κ-CN E and A variants, as well as β-LG B, and the predominant composite genotype of β- and κ-CN in the NC group was A2A2/AA. Generally, the A2A2/AA composite genotype was related to lower relative concentrations of κ-CN isoforms and higher relative concentrations of αS1-, αS2-, and β-CN. Compared with the group of WC milk samples, NC milk contained a higher fraction of αS2-CN and α-lactalbumin (α-LA) but a lower fraction of αS1-CN 9P. In conclusion, milk from native Swedish breeds has good characteristics for cheese milk, which could be exploited in niche dairy products. In milk from Swedish Mountain cows, levels of ionic calcium seemed to be more important for rennet-induced gel firmness than variation in the relative protein profile. In Swedish Red, lower protein content as well as higher fraction of αS2-CN and lower fraction of αS1-CN 9P were related to NC milk. Further, a decrease in the frequency of the composite β-κ-CN genotype A2A2/AA through selective breeding could have a positive effect on milk coagulation properties.
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| 38. |
- Poulsen, N. A., et al.
(författare)
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The influence of feed and herd on fatty acid composition in 3 dairy breeds (Danish Holstein, Danish Jersey, and Swedish Red)
- 2012
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 95:11, s. 6362-6371
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Tidskriftsartikel (refereegranskat)abstract
- The composition of milk fat from dairy cows is related to both genetic and environmental factors. Here, the effect of feed and herd was examined in 3 Scandinavian breeds, namely Danish Holstein-Friesian (DH), Danish Jersey (DJ), and Swedish Red (SR). In total, milk samples from 1,298 cows kept in indoor housing systems were collected from 61 conventional dairy herds in Denmark and Sweden. The fatty acid (FA) composition of milk was determined by gas chromatography and the content of alpha-tocopherol by HPLC. Based on the 17 individual FA determined, distinct FA profiles were observed for all breeds using univariate and multivariate statistics. The DJ cows were characterized by higher levels of saturated short-chain FA; in contrast, DH cows had higher content of unsaturated C18 FA, whereas higher levels of primarily C14:0, C14:1, C18:1 cis-9, and C18:3n-3 were evident in SR cows. This variation in milk fat composition across breeds was further reflected in different desaturase indices, which were generally higher in SR cows. In addition, alpha-tocopherol differed significantly among breeds, with DJ cows having the highest content. Herd-specific feeding plans were collected, and different feed items were separated into 4 broad feed categories, including grass products, maize silage, grain, and concentrate. The pronounced differences in overall feed composition among breeds were, to a large extent, due to regional differences between countries, with SR receiving higher levels of grain and grass silage compared with the Danish breeds. Within breeds, differences in feeding regimens among herds were furthermore higher in SR. Significant correlations between feed category and individual FA were observed in all breeds. Furthermore, variance components were estimated and used to determine the proportion of phenotypic variation that could be explained by herd. The herd effect for individual FA was generally lower for DH compared with the 2 other breeds. In addition, very low herd effects were shown for C14:1 and C16:1 in all breeds, suggesting that the content of these FA is mainly genetically regulated.
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| 39. |
- Sheng, Bulei, et al.
(författare)
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Effects of genetic variants and sialylation on in vitro digestibility of purified κ-casein
- 2022
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302. ; 105:4, s. 2803-2814
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Tidskriftsartikel (refereegranskat)abstract
- Milk with different κ-casein (CN) phenotypes has previously been found to influence its gastric digestion rate. Therefore, the aim of the present study is to disentangle contributions of genetic variation and its related sialylation on the in vitro digestion process of κ-CN. Accordingly, κ-CN was purified from milk representing homozygous cows with κ-CN phenotypes AA, BB, or EE and used as substrate molecules in model studies using the INFOGEST 2.0 in vitro static digestion model. Furthermore, the effect of removal of the terminal sialic acids present on the O-linked oligosaccharides of the purified κ-CN A, B, and E protein variants were studied by desialylation enzymatic assays. The κ-CN proteins were purified by reducing anion exchange chromatography with purities of variants A, B, and E of 93.0, 97.1, and 90.0%, respectively. Protein degradations of native and desialylated κ-CN isolates in gastric and intestinal phases were investigated by sodium dodecyl sulfate-PAGE, degree of hydrolysis (DH), and liquid chromatography electrospray ionization mass spectrometry. It was shown that after purification, the κ-CN molecules reassembled into multimer states, which then constituted the basis for the digestion studies. As assessed by DH, purified variants A and E were found to exhibit faster in vitro digestion rates in both gastric and intestinal phases compared with variant B. Desialylation increased both gastric and intestinal digestion rates for all variants, as measured by DH. In the gastric phase, desialylation promoted digestion of variant B at a rate comparable with native variants A and E, whereas in the intestinal phase, desialylation of variant B promoted better digestion than native A or E. Taken together, the results confirm that low glycosylation degree of purified κ-CN promotes faster in vitro digestion rates, and that desialylation of the O-linked oligosaccharides further promotes digestion. This finding could be applied to produce dairy products with enhanced digestibility.
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| 40. |
- Sheng, Bulei, et al.
(författare)
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Influence of genetic variants and sialylation of purified κ-casein on peptide release during in vitro digestion
- 2023
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Ingår i: Food Chemistry Advances. - 2772-753X. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, digestion pattern of purified bovine κ-casein (κ-CN) variants A, B, E as well as desialylated variant B, using INFOGEST 2.0 in vitro gastrointestinal digestion were investigated using peptidomics. Peptide profiles of the digests were identified and quantified using ion abundancies by liquid chromatography electrospray quadropole time of flight mass spectrometry (LC-ESI/Q-TOF MS/MS). Results showed that the κ-CN variants A and E had comparable digestion patterns at most digestion time points. In the in vitro gastric and in the initial intestinal phases fewer peptides and with lower total abundances were identified for variant B compared to variants A and E, indicating a slower digestion rate for κ-CN B. By desialylation, the digestion rate of desialylated variant B in both gastric and initial intestinal phases increased compared to the natural sialylated counterpart. Bioinformatics search revealed nine potential bioactive peptides released from all three variants A, B and E by the in vitro intestinal digestion, with four additional potential bioactive peptides being released after desialylation of κ-CN B.
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| 41. |
- Sheng, Bulei, et al.
(författare)
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Phosphorylation and glycosylation isoforms of bovine κ-casein variant E in homozygous Swedish Red cow milk by liquid chromatography-electrospray ionization mass spectrometry
- 2022
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302. ; 105:3, s. 1959-1965
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Tidskriftsartikel (refereegranskat)abstract
- Variations in the phosphorylation and glycosylation patterns of the common κ-casein (CN) variants A and B have been explored, whereas studies on variant E heterogeneity are scarce. This study reports for the first time the detailed phosphorylation and glycosylation pattern of the κ-CN variant E in comparison with variants A and B. Individual cow milk samples representing κ-CN genotype EE (n = 12) were obtained from Swedish Red cows, and the natural posttranslational modifications of its κ-CN were identified and quantified by liquid chromatography-electrospray mass spectrometry. In total, 12 unique isoform masses of κ-CN variant E were identified. In comparison, AA and BB milk consisted of 14 and 17 unique isoform masses, respectively. The most abundant κ-CN E isoform detected in the EE milk was the monophosphorylated, unglycosylated [1P 0G, ∼70%; where P indicates phosphorylation from single to triple phosphorylation (1–3P), and G indicates glycosylation from single to triple glycosylation (1–3G)] form, followed by diphosphorylated, unglycosylated (2P 0G, ∼12%) form, resembling known patterns from variants A and B. However, a clear distinction was the presence of the rare triphosphorylated, nonglycosylated (3P 0G, ∼0.05%) κ-CN isoform in the EE milk. All isoforms detected in variant E were phosphorylated, giving a phosphorylation degree of 100%. This is comparable with the phosphorylation degree of variants A and B, being also almost 100%, though with very small amounts of nonphosphorylated, glycosylated isoforms detected. The glycosylation degree of variant E was found to be around 17%, a bit higher than observed for variant B (around 14%), and higher than variant A (around 7%). Among glycosylation, the glycan e was the most common type identified for all 3 variants, followed by c/d (straight and branched chain trisaccharides, respectively), and b. In contrast to κ-CN variants A and B, no glycan of type a was found in variant E. Taken together, this study shows that the posttranslational modification pattern of variant E resembles that of known variants to a large extent, but with subtle differences.
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| 42. |
- Sundekilde, Ulrik K, et al.
(författare)
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Association between the bovine milk metabolome and rennet-induced coagulation properties of milk.
- 2014
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 1525-3198 .- 0022-0302. ; 97:10, s. 6076-6084
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Tidskriftsartikel (refereegranskat)abstract
- The milk metabolomes of 407 individual Swedish Red dairy cows were analyzed by nuclear magnetic resonance spectroscopy as part of the Danish-Swedish Milk Genomics Initiative. By relating these metabolite profiles to total milk protein concentration and rheological measurements of rennet-induced milk coagulation together using multivariate data analysis techniques, we were able to identify several different associations of the milk metabolome to technological properties of milk. Several novel correlations of milk metabolites to protein content and rennet-induced coagulation properties were demonstrated. Metabolites associated with the prediction of total protein content included choline, N-acetyl hexosamines, creatinine, glycerophosphocholine, glutamate, glucose 1-phosphate, galactose 1-phosphate, and orotate. In addition, levels of lactate, acetate, glutamate, creatinine, choline, carnitine, galactose 1-phosphate, and glycerophosphocholine were significantly different when comparing noncoagulating and well-coagulating milks. These findings suggest that the mentioned metabolites are associated with milk protein content and rennet-induced coagulation properties and may act as quality markers for cheese milk.
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