Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments
International audience Casein is the main milk protein component. It exists in milk as a suspension of large spherical particles called casein micelles. These colloidal particles can be destabilized in different ways, by addition of rennet, by slow acidification, or by combinations of both. Various...
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ftccsdartic:oai:HAL:hal-02591323v1 2023-05-15T16:52:22+02:00 Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments Mariette, François Le Feunteun, Steven Technologie des équipements agroalimentaires (UR TERE) Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF) UNIVERSITE EUROPEENNE DE BRETAGNE FRA Partenaires IRSTEA Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) Reykjavík, Iceland 2008-09-15 https://hal.inrae.fr/hal-02591323 en eng HAL CCSD hal-02591323 https://hal.inrae.fr/hal-02591323 IRSTEA: PUB00025356 9th International Conference on the Applications of Magnetic Resonance in Food Science "Challenges in a Changing World" https://hal.inrae.fr/hal-02591323 9th International Conference on the Applications of Magnetic Resonance in Food Science "Challenges in a Changing World", Sep 2008, Reykjavík, Iceland. pp.9 [SDE]Environmental Sciences info:eu-repo/semantics/conferenceObject Conference papers 2008 ftccsdartic 2021-08-21T22:45:36Z International audience Casein is the main milk protein component. It exists in milk as a suspension of large spherical particles called casein micelles. These colloidal particles can be destabilized in different ways, by addition of rennet, by slow acidification, or by combinations of both. Various parameters influenced the dynamics of the coagulation process. Depending on these conditions, the gel microstructure and its rheological properties, which are very important attributes of the product, can therefore be very different. The extent of the structural rearrangements that occur during the ageing of the fresh gel seems to be of primary importance, but although it is possible to highlight their effects, no ideal technique exists to investigate their dynamics. In the present study, we used a time-resolved Pulsed Field Gradient NMR method to investigate how and when probe diffusion rates vary during the coagulation process of dairy protein. The self-diffusion of a small and a large poly(ethylene glycol) (PEG) were monitored during the sol-gel transition of a casein system induced by chymosin, pH changes or a combination of both. Rheological measurements revealed that the diffusion rate of the molecules studied was unaffected by the establishment of a network. However, different evolutions occurred during the gel ageing phase, depending on the size of the diffusing molecule. The diffusion of the large PEG was very sensitive to variations in the size of the casein particles and the casein aggregates constituting the network before and after gelation, respectively. In contrast, the diffusion of the small PEG was sensitive to changes in the internal structure of the colloidal matter. Scanning electron microscopy images showed that all these findings could be explained by the progressive compaction of the casein network caused by the occurrence of structural rearrangements. This study demonstrates the sensitivity of probe diffusion to structural changes in casein gels, and also the potential of PFG-NMR techniques ... Conference Object Iceland Reykjavík Reykjavík Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Reykjavík |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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English |
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[SDE]Environmental Sciences |
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[SDE]Environmental Sciences Mariette, François Le Feunteun, Steven Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience Casein is the main milk protein component. It exists in milk as a suspension of large spherical particles called casein micelles. These colloidal particles can be destabilized in different ways, by addition of rennet, by slow acidification, or by combinations of both. Various parameters influenced the dynamics of the coagulation process. Depending on these conditions, the gel microstructure and its rheological properties, which are very important attributes of the product, can therefore be very different. The extent of the structural rearrangements that occur during the ageing of the fresh gel seems to be of primary importance, but although it is possible to highlight their effects, no ideal technique exists to investigate their dynamics. In the present study, we used a time-resolved Pulsed Field Gradient NMR method to investigate how and when probe diffusion rates vary during the coagulation process of dairy protein. The self-diffusion of a small and a large poly(ethylene glycol) (PEG) were monitored during the sol-gel transition of a casein system induced by chymosin, pH changes or a combination of both. Rheological measurements revealed that the diffusion rate of the molecules studied was unaffected by the establishment of a network. However, different evolutions occurred during the gel ageing phase, depending on the size of the diffusing molecule. The diffusion of the large PEG was very sensitive to variations in the size of the casein particles and the casein aggregates constituting the network before and after gelation, respectively. In contrast, the diffusion of the small PEG was sensitive to changes in the internal structure of the colloidal matter. Scanning electron microscopy images showed that all these findings could be explained by the progressive compaction of the casein network caused by the occurrence of structural rearrangements. This study demonstrates the sensitivity of probe diffusion to structural changes in casein gels, and also the potential of PFG-NMR techniques ... |
author2 |
Technologie des équipements agroalimentaires (UR TERE) Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF) UNIVERSITE EUROPEENNE DE BRETAGNE FRA Partenaires IRSTEA Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA) |
format |
Conference Object |
author |
Mariette, François Le Feunteun, Steven |
author_facet |
Mariette, François Le Feunteun, Steven |
author_sort |
Mariette, François |
title |
Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments |
title_short |
Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments |
title_full |
Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments |
title_fullStr |
Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments |
title_full_unstemmed |
Microstructure investigation of concentrated dairy gels by real-time NMR diffusion experiments |
title_sort |
microstructure investigation of concentrated dairy gels by real-time nmr diffusion experiments |
publisher |
HAL CCSD |
publishDate |
2008 |
url |
https://hal.inrae.fr/hal-02591323 |
op_coverage |
Reykjavík, Iceland |
geographic |
Reykjavík |
geographic_facet |
Reykjavík |
genre |
Iceland Reykjavík Reykjavík |
genre_facet |
Iceland Reykjavík Reykjavík |
op_source |
9th International Conference on the Applications of Magnetic Resonance in Food Science "Challenges in a Changing World" https://hal.inrae.fr/hal-02591323 9th International Conference on the Applications of Magnetic Resonance in Food Science "Challenges in a Changing World", Sep 2008, Reykjavík, Iceland. pp.9 |
op_relation |
hal-02591323 https://hal.inrae.fr/hal-02591323 IRSTEA: PUB00025356 |
_version_ |
1766042558405804032 |