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Updated: May 12, 2026
04:58
Embedded Bioprinting of Tissue-like Structures Using κ-Carrageenan Sub-Microgel Medium
Published on: May 3, 2024
Molecular mobility and microscopic structure changes in κ-carrageenan solutions studied by gradient NMR
Qiuhua Zhao1, Tom Brenner, Shingo Matsukawa
1Department of Food Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Tokyo 108-8477, Japan.
Carbohydrate Polymers
|April 27, 2013
Summary
Carrageenan
Area of Science:
- Polymer Science
- Physical Chemistry
- Materials Science
Background:
- Understanding the sol-to-gel transition in biopolymers like carrageenan is crucial for food and pharmaceutical applications.
- Molecular mobility dictates the physical properties and network formation during gelation.
Purpose of the Study:
- To elucidate the molecular mechanisms underlying the sol-to-gel transition of kappa-carrageenan.
- To investigate the role of molecular weight distribution in carrageenan gelation.
Main Methods:
- Pulsed field gradient stimulated echo (PGSTE) and Carr-Purcell-Meiboom-Gill (CPMG) NMR techniques were employed.
- Diffusion coefficients of carrageenan and a probe molecule (pullulan) were measured.
- Gel Permeation Chromatography (GPC) was used to confirm molecular weight distributions.
Main Results:
- A steep decrease in carrageenan echo signal intensity near the sol-to-gel temperature (Tsg) indicated aggregation and network formation.
- Below Tsg, lower molecular weight carrageenan chains were observed to coexist with higher molecular weight chains forming the gel network.
- The diffusion of pullulan was restricted by higher molecular weight carrageenan chains, while lower molecular weight chains influenced viscosity.
Conclusions:
- The sol-to-gel transition of kappa-carrageenan involves a bimodal molecular weight distribution.
- Higher molecular weight chains form the gel network, restricting probe diffusion.
- Lower molecular weight chains contribute to increased solution viscosity.
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