The Experts below are selected from a list of 106977 Experts worldwide ranked by ideXlab platform
Harjinder Singh - One of the best experts on this subject based on the ideXlab platform.
-
small and large deformation rheology and microstructure of κ carrageenan gels containing commercial Milk Protein products
International Dairy Journal, 2002Co-Authors: Yacine Hemar, Peter A Munro, Christopher E Hall, Harjinder SinghAbstract:Abstract The rheological behaviour of commercial Milk Protein/ κ -carrageenan mixtures in aqueous solutions was studied at neutral pH. Four Milk Protein ingredients; skim Milk powder, Milk Protein concentrate, sodium caseinate, and whey Protein isolate were considered. As seen by confocal laser microscopy, mixtures of κ -carrageenan with skim Milk powder, Milk Protein concentrate, and sodium caseinate showed phase separation, but no phase separation was observed in mixtures containing whey Protein isolate. For κ -carrageenan concentrations up to 0.5 wt%, the viscosity of the mixtures at low shear rates increased markedly in the case of skim Milk powder and Milk Protein concentrate addition, but did not change by the addition of sodium caseinate or whey Protein isolate. For κ -carrageenan concentrations from 1 to 2.5 wt%, small and large deformation rheological measurements, performed on the Milk Protein/ κ -carrageenan gels, showed that skim Milk powder, Milk Protein concentrate or sodium caseinate markedly improved the strength of the resulting gels, but whey Protein isolate had no effect on the gel stength.
-
viscosity microstructure and phase behavior of aqueous mixtures of commercial Milk Protein products and xanthan gum
Food Hydrocolloids, 2001Co-Authors: Yacine Hemar, M Tamehana, Peter A Munro, Harjinder SinghAbstract:Abstract The behavior of commercial Milk Protein/xanthan mixtures was studied at neutral pH. Four Milk Protein ingredients; skim Milk powder, Milk Protein concentrate, sodium caseinate and whey Protein isolate were considered. For the xanthan concentrations used, up to 1wt%, the viscosity of the mixtures was dominated by the viscosity of xanthan. Mixtures of xanthan with skim Milk powder or Milk Protein concentrate showed phase separation, as seen by confocal micrographs, and phase diagrams have been established for these two systems. No visible phase separation was observed in the case of mixtures of sodium caseinate or whey Protein isolate systems. However, mixtures of sodium caseinate and xanthan, under certain conditions, showed formation of ‘thread-like’ xanthan-rich regions by confocal microscopy. We believe that the phase separation occurring in Milk Protein concentrate/xanthan or skim Milk powder/xanthan mixtures was a result of depletion flocculation of casein micelles by the xanthan macromolecules, but thermodynamic incompatibility was likely to occur in sodium caseinate/xanthan mixtures.
Kevin R Nicholas - One of the best experts on this subject based on the ideXlab platform.
-
insulin a key regulator of hormone responsive Milk Protein synthesis during lactogenesis in murine mammary explants
Functional & Integrative Genomics, 2010Co-Authors: K L Macmillan, Karensa Menzies, Christophe Lefevre, Kevin R Nicholas, Heather J Lee, Christopher J OrmandyAbstract:Murine Milk Protein gene expression requires insulin, hydrocortisone, and prolactin; however, the role of insulin is not well understood. This study, therefore, examined the requirement of insulin for Milk Protein synthesis. Mammary explants were cultured in various combinations of the lactogenic hormones and global changes in gene expression analysed using Affymetrix microarray. The expression of 164 genes was responsive to insulin, and 18 were involved in Protein synthesis at the level of transcription and posttranscription, as well as amino acid uptake and metabolism. The folate receptor gene was increased by fivefold, highlighting a potentially important role for the hormone in folate metabolism, a process that is emerging to be central for Protein synthesis. Interestingly, gene expression of two Milk Protein transcription factors, Stat5a and Elf5, previously identified as key components of prolactin signalling, both showed an essential requirement for insulin. Subsequent experiments in HCll cells confirmed that Stat5a and Elf5 gene expression could be induced in the absence of prolactin but in the presence of insulin. Whereas prolactin plays an essential role in phosphorylating and activating Stat5a, gene expression is only induced when insulin is present. This indicates insulin plays a crucial role in the transcription of the Milk Protein genes.
-
insulin regulates Milk Protein synthesis at multiple levels in the bovine mammary gland
Functional & Integrative Genomics, 2009Co-Authors: Karensa Menzies, K L Macmillan, Christophe Lefevre, Kevin R NicholasAbstract:The role of insulin in Milk Protein synthesis is unresolved in the bovine mammary gland. This study examined the potential role of insulin in the presence of two lactogenic hormones, hydrocortisone and prolactin, in Milk Protein synthesis. Insulin was shown to stimulate Milk Protein gene expression, casein synthesis and 14C-lysine uptake in mammary explants from late pregnant cows. A global assessment of changes in gene expression in mammary explants in response to insulin was undertaken using Affymetrix microarray. The resulting data provided insight into the molecular mechanisms stimulated by insulin and showed that the hormone stimulated the expression of 28 genes directly involved in Protein synthesis. These genes included the Milk Protein transcription factor, ELF5, translation factors, the folate metabolism genes, FOLR1 and MTHFR, as well as several genes encoding enzymes involved in catabolism of essential amino acids and biosynthesis of non-essential amino acids. These data show that insulin is not only essential for Milk Protein gene expression, but stimulates Milk Protein synthesis at multiple levels within bovine mammary epithelial cells.
Yacine Hemar - One of the best experts on this subject based on the ideXlab platform.
-
small and large deformation rheology and microstructure of κ carrageenan gels containing commercial Milk Protein products
International Dairy Journal, 2002Co-Authors: Yacine Hemar, Peter A Munro, Christopher E Hall, Harjinder SinghAbstract:Abstract The rheological behaviour of commercial Milk Protein/ κ -carrageenan mixtures in aqueous solutions was studied at neutral pH. Four Milk Protein ingredients; skim Milk powder, Milk Protein concentrate, sodium caseinate, and whey Protein isolate were considered. As seen by confocal laser microscopy, mixtures of κ -carrageenan with skim Milk powder, Milk Protein concentrate, and sodium caseinate showed phase separation, but no phase separation was observed in mixtures containing whey Protein isolate. For κ -carrageenan concentrations up to 0.5 wt%, the viscosity of the mixtures at low shear rates increased markedly in the case of skim Milk powder and Milk Protein concentrate addition, but did not change by the addition of sodium caseinate or whey Protein isolate. For κ -carrageenan concentrations from 1 to 2.5 wt%, small and large deformation rheological measurements, performed on the Milk Protein/ κ -carrageenan gels, showed that skim Milk powder, Milk Protein concentrate or sodium caseinate markedly improved the strength of the resulting gels, but whey Protein isolate had no effect on the gel stength.
-
viscosity microstructure and phase behavior of aqueous mixtures of commercial Milk Protein products and xanthan gum
Food Hydrocolloids, 2001Co-Authors: Yacine Hemar, M Tamehana, Peter A Munro, Harjinder SinghAbstract:Abstract The behavior of commercial Milk Protein/xanthan mixtures was studied at neutral pH. Four Milk Protein ingredients; skim Milk powder, Milk Protein concentrate, sodium caseinate and whey Protein isolate were considered. For the xanthan concentrations used, up to 1wt%, the viscosity of the mixtures was dominated by the viscosity of xanthan. Mixtures of xanthan with skim Milk powder or Milk Protein concentrate showed phase separation, as seen by confocal micrographs, and phase diagrams have been established for these two systems. No visible phase separation was observed in the case of mixtures of sodium caseinate or whey Protein isolate systems. However, mixtures of sodium caseinate and xanthan, under certain conditions, showed formation of ‘thread-like’ xanthan-rich regions by confocal microscopy. We believe that the phase separation occurring in Milk Protein concentrate/xanthan or skim Milk powder/xanthan mixtures was a result of depletion flocculation of casein micelles by the xanthan macromolecules, but thermodynamic incompatibility was likely to occur in sodium caseinate/xanthan mixtures.
B A Murray - One of the best experts on this subject based on the ideXlab platform.
-
Solubility of commercial Milk Protein concentrates and Milk Protein isolates
Journal of Dairy Science, 2011Co-Authors: V. Sikand, Luis E. Rodriguez-saona, P S Tong, S Roy, B A MurrayAbstract:High-Protein Milk Protein concentrate (MPC) and Milk Protein isolate (MPI) powders may have lower solubility than low-Protein MPC powders, but information is limited on MPC solubility. Our objectives in this study were to (1) characterize the solubility of commercially available powder types with differing Protein contents such as MPC40, MPC80, and MPI obtained from various manufacturers (sources), and (2) determine if such differences could be associated with differences in mineral, Protein composition, and conformational changes of the powders. To examine possible predictors of solubility as measured by percent suspension stability (%SS), mineral analysis, Fourier transform infrared (FTIR) spectroscopy, and quantitative Protein analysis by HPLC was performed. After accounting for overall differences between powder types, %SS was found to be strongly associated with the calcium, magnesium, phosphorus, and sodium content of the powders. The FTIR score plots were in agreement with %SS results. A principal component analysis of FTIR spectra clustered the highly soluble MPC40 separately from the rest of samples. Furthermore, 2 highly soluble MPI samples were clustered separately from the rest of the MPC80 and MPI samples. We found that the 900 to 1,200 cm⁻¹ region exhibited the highest discriminating power, with dominant bands at 1,173 and 968 cm⁻¹, associated with phosphate vibrations. The 2 highly soluble MPI powders were observed to have lower κ-casein and α-(S1)-casein contents and slightly higher whey Protein contents than the other powders. The differences in the solubility of MPC and MPI were associated with a difference in mineral composition, which may be attributed to differences in processing conditions. Additional studies on the role of minerals composition on MPC80 solubility are warranted. Such a study would provide a greater understanding of factors associated with differences in solubility and can provide insight on methods to improve solubility of high-Protein Milk Protein concentrates.
K L Macmillan - One of the best experts on this subject based on the ideXlab platform.
-
Milk Protein concentration estimated breeding value for fertility and reproductive performance in lactating dairy cows
Journal of Dairy Science, 2017Co-Authors: J M Morton, M J Auldist, Meaghan L Douglas, K L MacmillanAbstract:Milk Protein concentration in dairy cows has been positively associated with a range of measures of reproductive performance, and genetic factors affecting both Milk Protein concentration and reproductive performance may contribute to the observed phenotypic associations. It was of interest to assess whether these beneficial phenotypic associations are accounted for or interact with the effects of estimated breeding values for fertility. The effects of a multitrait estimated breeding value for fertility [the Australian breeding value for daughter fertility (ABV fertility)] on reproductive performance were also of interest. Interactions of Milk Protein concentration and ABV fertility with the interval from calving date to the start of the herd's seasonally concentrated breeding period were also assessed. A retrospective single cohort study was conducted using data collected from 74 Australian seasonally and split calving dairy herds. Associations between Milk Protein concentration, ABV fertility, and reproductive performance in Holstein cows were assessed using random effects logistic regression. Between 52,438 and 61,939 lactations were used for analyses of 4 reproductive performance measures. Milk Protein concentration was strongly and positively associated with reproductive performance in dairy cows, and this effect was not accounted for by the effects of ABV fertility. Increases in ABV fertility had important additional beneficial effects on the probability of pregnancy by wk 6 and 21 of the herd's breeding period. For cows calved before the start of the breeding period, the effects of increases in both Milk Protein concentration and ABV fertility were beneficial regardless of their interval from calving to the start of the breeding period. These findings demonstrate the potential for increasing reproductive performance through identifying the causes of the association between Milk Protein concentration and reproductive performance and then devising management strategies to capitalize on them. Research should be conducted to understand the component of the relationship not captured by ABV fertility.
-
associations between Milk Protein concentration Milk yield and reproductive performance in dairy cows
Journal of Dairy Science, 2016Co-Authors: J M Morton, M J Auldist, Meaghan L Douglas, K L MacmillanAbstract:Milk Protein concentration in dairy cows has been positively associated with a range of measures of reproductive performance. It was possible that these associations were due to confounding by Milk volume. A retrospective single cohort study was conducted using data collected from 74 dairy herds with seasonal or split calving patterns. Associations between Milk Protein concentration and reproductive performance in Holstein dairy cows were assessed using random effects logistic regression. The key finding from this study was that the associations between Milk Protein concentration in early lactation and reproductive performance were not due to confounding by Milk yield. Associations between Milk Protein concentration and reproductive performance were weaker at higher early lactation Milk yields, but positive associations were evident at all Milk volumes assessed. The second major finding was that increases in Milk yield were associated with improved proportions of cows pregnant by wk 6 and 21 at low to moderate Milk Protein concentrations but with decreases in these reproductive measures at high Milk Protein concentrations. Thus, no simple relationship is present between Milk yield and reproductive performance; effects of Milk yield depend on Milk Protein concentration. These results indicate that mechanisms causing the associations between Milk Protein concentration and reproductive performance may be linked to Milk yield but these mechanisms operate over a wide range of Milk yields (<2,000 to ≥5,000kg in the first 120d of lactation). Further research is required to identify the causes of these associations.
-
insulin a key regulator of hormone responsive Milk Protein synthesis during lactogenesis in murine mammary explants
Functional & Integrative Genomics, 2010Co-Authors: K L Macmillan, Karensa Menzies, Christophe Lefevre, Kevin R Nicholas, Heather J Lee, Christopher J OrmandyAbstract:Murine Milk Protein gene expression requires insulin, hydrocortisone, and prolactin; however, the role of insulin is not well understood. This study, therefore, examined the requirement of insulin for Milk Protein synthesis. Mammary explants were cultured in various combinations of the lactogenic hormones and global changes in gene expression analysed using Affymetrix microarray. The expression of 164 genes was responsive to insulin, and 18 were involved in Protein synthesis at the level of transcription and posttranscription, as well as amino acid uptake and metabolism. The folate receptor gene was increased by fivefold, highlighting a potentially important role for the hormone in folate metabolism, a process that is emerging to be central for Protein synthesis. Interestingly, gene expression of two Milk Protein transcription factors, Stat5a and Elf5, previously identified as key components of prolactin signalling, both showed an essential requirement for insulin. Subsequent experiments in HCll cells confirmed that Stat5a and Elf5 gene expression could be induced in the absence of prolactin but in the presence of insulin. Whereas prolactin plays an essential role in phosphorylating and activating Stat5a, gene expression is only induced when insulin is present. This indicates insulin plays a crucial role in the transcription of the Milk Protein genes.
-
insulin regulates Milk Protein synthesis at multiple levels in the bovine mammary gland
Functional & Integrative Genomics, 2009Co-Authors: Karensa Menzies, K L Macmillan, Christophe Lefevre, Kevin R NicholasAbstract:The role of insulin in Milk Protein synthesis is unresolved in the bovine mammary gland. This study examined the potential role of insulin in the presence of two lactogenic hormones, hydrocortisone and prolactin, in Milk Protein synthesis. Insulin was shown to stimulate Milk Protein gene expression, casein synthesis and 14C-lysine uptake in mammary explants from late pregnant cows. A global assessment of changes in gene expression in mammary explants in response to insulin was undertaken using Affymetrix microarray. The resulting data provided insight into the molecular mechanisms stimulated by insulin and showed that the hormone stimulated the expression of 28 genes directly involved in Protein synthesis. These genes included the Milk Protein transcription factor, ELF5, translation factors, the folate metabolism genes, FOLR1 and MTHFR, as well as several genes encoding enzymes involved in catabolism of essential amino acids and biosynthesis of non-essential amino acids. These data show that insulin is not only essential for Milk Protein gene expression, but stimulates Milk Protein synthesis at multiple levels within bovine mammary epithelial cells.