Hydrodynamic properties–structure relationship for sodium caseinates in presence of calcium

Alvarez, Estela M.; Risso, Patricia Hilda; Canales, Marco; Pires, Miryam S.; Gatti, Carlos A.

doi:10.1016/j.colsurfa.2008.06.003

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…These results would indicate the formation of CCA with a more compact structure when calcium is present, according to that reported for bovine CCA …”

Section: Resultssupporting

confidence: 83%

“…These results would indicate the formation of CCA with a more compact structure when calcium is present, according to that reported for bovine CCA. 33 In the studied range of calcium concentrations ((0 to 2.5) mmol • L -1 ), in which the ovine caseinate solubility is not affected (Figure 1A), two contrary effects upon S H may be inferred from the data obtained. On the one hand, as TCC increases, the average size of the aggregates in suspension decreases (Figure 2C) as a direct consequence of a dissociation process undergone by CCA, which favors the exposure of hydrophobic patches.…”

Section: S App )mentioning

confidence: 81%

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Effect of Calcium on Ovine Caseinate Functional Properties

et al. 2010

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The solubility of colloidal particles of ovine caseinate in the presence of calcium was followed by analyzing the colloidal particle size and the protein composition of colloidal particles remaining in suspension. A comparison between the behavior of bovine and ovine caseinate was carried out. A sequential two-step salting-out process, due to progressive Ca2+ binding to at least two kinds of sites, was observed for both caseinates. The precipitation curves were fitted, and the affinity constants and binding site numbers were calculated with an equation based on the concept of Wyman’s linked functions. Ovine caseinate colloidal aggregates obtained in the presence of calcium turned out to be less stable and bigger than the bovine ones. Calcium binding to protein residues modifies the composition and the conformation of caseinates. An aggregation process at low ovine caseinate concentrations and a gelation process at high protein concentrations induced by glucono-δ-lactone hydrolysis were studied in the presence of calcium concentrations where no precipitation is observed. The presence of calcium affects the kinetics of both processes and the final state of aggregates and gels network formed. The degree of compactness, average size of the aggregates, and rheological properties of gels formed at the end of the acidification process depend on the calcium concentration added.

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“…These results would indicate the formation of CCA with a more compact structure when calcium is present, according to that reported for bovine CCA …”

Section: Resultssupporting

confidence: 83%

Section: S App )mentioning

confidence: 81%

Effect of Calcium on Ovine Caseinate Functional Properties

et al. 2010

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“…Added calcium ions bind specifically to caseins and can lead to aggregation of the caseinate particles. Alvarez et al 21 reported changes in the intrinsic viscosity, fluorescence and circular dichroism spectra when CaCl 2 was added to dilute NaCas suspensions, which they attributed to the formation of increasingly dense aggregates. At higher CaCl 2 concentrations an increasing fraction of the proteins precipitates with increasing CaCl 2 concentration.…”

Section: Introductionmentioning

confidence: 99%

Slow dynamics and structure in jammed milk protein suspensions

et al. 2012

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The dynamic mechanical properties and the structure of dense suspensions of sodium caseinate were investigated using oscillatory shear theology and confocal laser scanning microscopy, respectively. Caseins are the most abundant milk proteins and form in the absence of calcium phosphate small star-like particles with radii of about 10 nm. The viscosity increases strongly with increasing protein concentration above -80 g L(-1) due to jamming of the particles. The viscosity increase is stronger at lower temperatures, caused by a strong decrease in the terminal relaxation time with increasing temperature. Addition of calcium ions introduces an attractive interaction that induces phase separation above a critical calcium concentration. Increasing the CaCl2 concentration leads to an increase in the terminal relaxation time, but to a decrease in the high frequency elastic modulus. The effect of adding CaCl2 is stronger at higher temperatures.

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“…Intrinsic viscosities of samples ([η]), related to the protein conformation, are defined by the following equation: false[ normalη false] = lim c 2 → 0 ( η / η 0 ) − 1 c 2 where c 2 is the protein concentration in (0.006 to 0.014) g·mL −1 and η and η 0 are the solutions and solvent viscosities, respectively. The [η] was determined by η measurements of diluted solution series, plotting ((η/η 0 ) − 1)/ c 2 versus c 2 and extrapolating to zero concentration …”

Section: Methodsmentioning

confidence: 99%

“…The [η] was determined by η measurements of diluted solution series, plotting ((η/η 0 ) -1)/c 2 versus c 2 and extrapolating to zero concentration. 18 The υ j 2 of a component of a solution for macromolecules which usually interact with the solvent depends on the solution concentration and is defined by:…”

Section: Methodsmentioning

confidence: 99%

Colloidal Stability of Bovine Calcium Caseinate Suspensions. Effect of Protein Concentration and the Presence of Sucrose and Lactose

et al. 2010

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Sodium caseinate suspensions (Cas) are stabilized as submicelles in a dynamic system consisting of caseins R, β, and κ. Their use in the food industry is quite widespread because of their functional properties and nutritional value. In the presence of calcium ions, Cas are able to form colloidal stable aggregates in suspension (CCA) at certain Ca 2+ and Cas concentration ratios (Ca:Cas). The aim of this work was to study the effect of the protein concentration on the CCA solubility and viscosity at different Ca:Cas and to relate those two functional properties to protein composition and conformational changes. The stability of CCA was also evaluated in the presence of lactose and sucrose. The apparent solubility of the CCA was determined by applying a spectrophotometric method, and the stability test parameters were obtained using a model based on thermodynamic linked functions. The protein conformational changes were followed by using fluorescence techniques and were related to the partial specific volume and the intrinsic viscosity. The experimental data obtained allowed us to conclude that the stability of CCA depends on the initial protein concentration for the same Ca:Cas ratio. A model based on multiple-step equilibrium was proposed as an approach to explain the stability of Cas against Ca 2+ . Furthermore, it was observed that the addition of Ca 2+ to Cas generates changes in the protein conformation, leading to more compact and symmetrical structures. The colloidal stability of the CCA was favored by the presence of sugars, especially by lactose.

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Hydrodynamic properties–structure relationship for sodium caseinates in presence of calcium

Cited by 8 publications

References 14 publications

Effect of Calcium on Ovine Caseinate Functional Properties

Effect of Calcium on Ovine Caseinate Functional Properties

Slow dynamics and structure in jammed milk protein suspensions

Colloidal Stability of Bovine Calcium Caseinate Suspensions. Effect of Protein Concentration and the Presence of Sucrose and Lactose

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