Chapter 8: NMR in Food Technology
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Published:07 Jul 2020
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Special Collection: 2020 ebook collectionSeries: New Developments in NMR
L. C. Geonzon, F. B. A. Descallar, and S. Matsukawa, in NMR and MRI of Gels, ed. Y. De Deene, The Royal Society of Chemistry, 2020, ch. 8, pp. 254-274.
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The application of nuclear magnetic resonance (NMR) techniques to elucidate the solution to gel transition of different food hydrocolloids is presented. The experimental results of NMR relaxation times and molecular mobility measurements of agar, agarose, gellan gum and carrageenan solutions are presented, which provide physical pictures describing the gelation mechanism and network structures of the gels. Relaxation time measurements of polysaccharide chains provided information on the tumbling motion and local mobility and flexibility of the chains. Diffusion measurements of polysaccharide chains and added probe polymers gave insights into the conformational changes of polysaccharide chains undergoing a transition from a solution to a gel, particularly the microscopic events of aggregation, polymer immobilization, and changes in probe diffusion during gelation. NMR measurements accompanied by different experimental techniques, such as optical dichroism, dynamic rheological measurements, differential scanning calorimetry and particle tracking, impart a clear picture at different length scales of observation of the gelation mechanism of polysaccharide gels.