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Updated: Feb 12, 2026

Author Spotlight: Development of Homogeneous κ-Carrageenan Sub-Microgel Baths for High-Resolution 3D Bioprinting
Published on: May 3, 2024
Characterisation of rheology and microstructures of κ-carrageenan in ethanol-water mixtures
Zhi Yang1, Huijuan Yang2, Hongshun Yang1
1Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore 117543, Republic of Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China.
Abstract:
The effects of ethanol (up to 20 wt%) on the rheological properties and structural characteristics of κ-carrageenan gel were investigated by Field Emission Scanning Electron Microscopy (FESEM) and Small Angle X-ray Scattering (SAXS). Both the sol-gel and gel-sol transition temperatures shifted to higher degree (from 36.8 ± 0.5 to 52.5 ± 1.4 °C and from 51.2 ± 0.6 to 67.0 ± 0.5 °C, respectively) upon 20 wt% ethanol addition (P < 0.05). The critical relaxation exponent n and the critical gel strength Sg obtained from Winter-Chambon criterion decreased and increased, respectively as the ethanol concentration increased. The κ-carrageenan gel was formed due to the formation of fibrillar networks, and the fibrillar density increased upon ethanol addition via FESEM. Moreover, upon 20 wt% ethanol addition, the average radius of gyration of κ-carrageenan strand increased from 1.18 ± 0.03 of control to 1.55 ± 0.02 nm by SAXS. A mechanism underlying the effect of ethanol on the κ-carrageenan gelation was proposed based on coil to double helix transition followed by the helix aggregation.
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