Structure-rheology relations in sodium caseinate containing systems
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
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Doctoral thesis biblioteca |
| Language: | English |
| Subjects: | acidification, emulsions, gelation, light, rheological properties, scattering, shear, sodium caseinate, spectroscopy, structure, afschuifkracht, emulsies, gelering, licht, natriumcaseïnaat, reologische eigenschappen, spectroscopie, structuur, verstrooiing, verzuring, |
| Online Access: | https://research.wur.nl/en/publications/structure-rheology-relations-in-sodium-caseinate-containing-syste |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|