Structure-rheology relations in sodium caseinate containing systems

H.G.M. Ruis

Research output: Thesisinternal PhD, WU

Abstract

The general aim of the work described in this thesis was to investigate structure-rheologyrelations for dairy related products, focusing on model systems containing sodium caseinate. The acid inducedgelationof sodium caseinate, of sodium caseinate stabilized emulsions, and the effect of shear on the structure formation was characterized. Special attention was given to the sol-gel transition point, which was defined by a frequency independent loss tangent. It was shown that the sol-gel transition point is completely controlled by the pH and the temperature, independent of the concentration sodium caseinate or the applied shear rate. Considering sodium caseinate solutions, increase of the temperature of acidification caused a decrease of the critical pH forgelationand a more dense gel structure. The formed gels were not in thermodynamicequilibrium,however, due to the slow kinetics of the system they were stable on the time scale of the experiment. At the gel point we have strong indications that the structure can not be characterized by a single fractal dimension. During the acid inducedgelationof sodium caseinate stabilized emulsions a single sol-gel transition was observed. Addition of an excess of sodium caseinate to the emulsion resulted in two sol-gel transitions upon acidification. Application of shear during the acidification of the emulsions showed a decreasing radius of the aggregates formed at thegelpointwith increasing shear rate. The aggregates formed becamemore densedue to the application of shear while the network that was formed by the aggregates became less compact. No shear induced alignment was observed of emulsion droplets dispersed in water or ina sodiumcaseinatesolution, while emulsion droplets dispersed in axanthansolution did align in a shear field. Addition of sodium inhibited the string formation of the emulsion droplets
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • van der Linden, Erik, Promotor
  • Venema, Paul, Co-promotor
Award date19 Jun 2007
Place of Publication[S.l.]
Publisher
Print ISBNs9789085046486
Publication statusPublished - 2007

Fingerprint

Caseins
Emulsions
Rheology
Sol-gels
Acidification
Gels
Shear deformation
Acids
Dairies
Fractal dimension
Sodium
Temperature
Kinetics
Water
Experiments

Keywords

  • sodium caseinate
  • rheological properties
  • shear
  • gelation
  • emulsions
  • structure
  • acidification
  • spectroscopy
  • light
  • scattering

Cite this

Ruis, H.G.M.. / Structure-rheology relations in sodium caseinate containing systems. [S.l.] : S.n., 2007. 125 p.
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title = "Structure-rheology relations in sodium caseinate containing systems",
abstract = "The general aim of the work described in this thesis was to investigate structure-rheologyrelations for dairy related products, focusing on model systems containing sodium caseinate. The acid inducedgelationof sodium caseinate, of sodium caseinate stabilized emulsions, and the effect of shear on the structure formation was characterized. Special attention was given to the sol-gel transition point, which was defined by a frequency independent loss tangent. It was shown that the sol-gel transition point is completely controlled by the pH and the temperature, independent of the concentration sodium caseinate or the applied shear rate. Considering sodium caseinate solutions, increase of the temperature of acidification caused a decrease of the critical pH forgelationand a more dense gel structure. The formed gels were not in thermodynamicequilibrium,however, due to the slow kinetics of the system they were stable on the time scale of the experiment. At the gel point we have strong indications that the structure can not be characterized by a single fractal dimension. During the acid inducedgelationof sodium caseinate stabilized emulsions a single sol-gel transition was observed. Addition of an excess of sodium caseinate to the emulsion resulted in two sol-gel transitions upon acidification. Application of shear during the acidification of the emulsions showed a decreasing radius of the aggregates formed at thegelpointwith increasing shear rate. The aggregates formed becamemore densedue to the application of shear while the network that was formed by the aggregates became less compact. No shear induced alignment was observed of emulsion droplets dispersed in water or ina sodiumcaseinatesolution, while emulsion droplets dispersed in axanthansolution did align in a shear field. Addition of sodium inhibited the string formation of the emulsion droplets",
keywords = "natriumcase{\"i}naat, reologische eigenschappen, afschuifkracht, gelering, emulsies, structuur, verzuring, spectroscopie, licht, verstrooiing, sodium caseinate, rheological properties, shear, gelation, emulsions, structure, acidification, spectroscopy, light, scattering",
author = "H.G.M. Ruis",
note = "WU thesis, no. 4218",
year = "2007",
language = "English",
isbn = "9789085046486",
publisher = "S.n.",
school = "Wageningen University",

}

Ruis, HGM 2007, 'Structure-rheology relations in sodium caseinate containing systems', Doctor of Philosophy, Wageningen University, [S.l.].

Structure-rheology relations in sodium caseinate containing systems. / Ruis, H.G.M.

[S.l.] : S.n., 2007. 125 p.

Research output: Thesisinternal PhD, WU

TY - THES

T1 - Structure-rheology relations in sodium caseinate containing systems

AU - Ruis, H.G.M.

N1 - WU thesis, no. 4218

PY - 2007

Y1 - 2007

N2 - The general aim of the work described in this thesis was to investigate structure-rheologyrelations for dairy related products, focusing on model systems containing sodium caseinate. The acid inducedgelationof sodium caseinate, of sodium caseinate stabilized emulsions, and the effect of shear on the structure formation was characterized. Special attention was given to the sol-gel transition point, which was defined by a frequency independent loss tangent. It was shown that the sol-gel transition point is completely controlled by the pH and the temperature, independent of the concentration sodium caseinate or the applied shear rate. Considering sodium caseinate solutions, increase of the temperature of acidification caused a decrease of the critical pH forgelationand a more dense gel structure. The formed gels were not in thermodynamicequilibrium,however, due to the slow kinetics of the system they were stable on the time scale of the experiment. At the gel point we have strong indications that the structure can not be characterized by a single fractal dimension. During the acid inducedgelationof sodium caseinate stabilized emulsions a single sol-gel transition was observed. Addition of an excess of sodium caseinate to the emulsion resulted in two sol-gel transitions upon acidification. Application of shear during the acidification of the emulsions showed a decreasing radius of the aggregates formed at thegelpointwith increasing shear rate. The aggregates formed becamemore densedue to the application of shear while the network that was formed by the aggregates became less compact. No shear induced alignment was observed of emulsion droplets dispersed in water or ina sodiumcaseinatesolution, while emulsion droplets dispersed in axanthansolution did align in a shear field. Addition of sodium inhibited the string formation of the emulsion droplets

AB - The general aim of the work described in this thesis was to investigate structure-rheologyrelations for dairy related products, focusing on model systems containing sodium caseinate. The acid inducedgelationof sodium caseinate, of sodium caseinate stabilized emulsions, and the effect of shear on the structure formation was characterized. Special attention was given to the sol-gel transition point, which was defined by a frequency independent loss tangent. It was shown that the sol-gel transition point is completely controlled by the pH and the temperature, independent of the concentration sodium caseinate or the applied shear rate. Considering sodium caseinate solutions, increase of the temperature of acidification caused a decrease of the critical pH forgelationand a more dense gel structure. The formed gels were not in thermodynamicequilibrium,however, due to the slow kinetics of the system they were stable on the time scale of the experiment. At the gel point we have strong indications that the structure can not be characterized by a single fractal dimension. During the acid inducedgelationof sodium caseinate stabilized emulsions a single sol-gel transition was observed. Addition of an excess of sodium caseinate to the emulsion resulted in two sol-gel transitions upon acidification. Application of shear during the acidification of the emulsions showed a decreasing radius of the aggregates formed at thegelpointwith increasing shear rate. The aggregates formed becamemore densedue to the application of shear while the network that was formed by the aggregates became less compact. No shear induced alignment was observed of emulsion droplets dispersed in water or ina sodiumcaseinatesolution, while emulsion droplets dispersed in axanthansolution did align in a shear field. Addition of sodium inhibited the string formation of the emulsion droplets

KW - natriumcaseïnaat

KW - reologische eigenschappen

KW - afschuifkracht

KW - gelering

KW - emulsies

KW - structuur

KW - verzuring

KW - spectroscopie

KW - licht

KW - verstrooiing

KW - sodium caseinate

KW - rheological properties

KW - shear

KW - gelation

KW - emulsions

KW - structure

KW - acidification

KW - spectroscopy

KW - light

KW - scattering

M3 - internal PhD, WU

SN - 9789085046486

PB - S.n.

CY - [S.l.]

ER -