PFG-NMR: a versatile tool for microstructure investigation of dairy protein gels
2011
Mariette, François | Le Feunteun, Steven
In the present study, we illustrate the potentiality of the PFG-NMR technique to investigate structural changes in dairy casein gels. 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 influence 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. To improve our understanding of the microstructure, different PFG-NMR approaches have been carrying out. The diffusion coefficient of poly(ethylene glycol) (PEG) polymers with varying molecular weights, used as probe, were compared in casein gels obtained with different coagulation processes [1,2]. A time-resolved PFG-NMR method to investigate how and when probe diffusion rates vary during the coagulation process of dairy protein was also implemented [2,3]. The last example will we focus on the study of the self-diffusion of non-aggregated casein molecules used as probe and compared with PEG [4].
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