Table 1.
Structural and elastic properties of Kappa gels prepared with salt conditions and carrageenan samples specified in the first column “System”. Mesh size ε, length L and diameter d of strands were obtained from electronic microscopy (EM), fluorescence recovery after photobleaching (FRAP), particles tracking (PT), atomic force microscopy (AFM), nuclear magnetic resonance (NMR), small angle X-ray scattering (SAXS) or wide angle X-ray scattering (WAXD). Column G0 reports the range of gel linear shear storage modulus G0 measured at temperatures between 10 and 25 °C. The last column lists the referenced literature for the corresponding row.
| Sample | Structural Features | Rheology | Ref. | |||
|---|---|---|---|---|---|---|
| Carrageean Form 1 | Salt | ε (nm) | L (nm) | d (nm) | G0 (kPa) | |
| Com. | No salt | 500–104 (EM 3) | 5 × 104 (EM 3) | 100–500 (EM 3) | 0.02–20 | [29] |
| Com. | No salt | 2 × 103–104 (EM 3) | 3 × 103–104 (EM 3) | 2.34 (SAXS) | 2.6 | [30] |
| Na | CaCl2 | Up to 5 × 104 (EM 3) | Up to 5 × 104 (EM 3) | 102–103 (EM 3) | 0.5–3.5 | [31] |
| Na | NaCl | 6 (WAXD) | >100 (AFM 3) | 1.1 (AFM) | 0.1 | [32] |
| K | KCl | 4.3 and 6 (WAXD) | >100 (AFM 3) | 1.5 (AFM) | 1.4 | [32] |
| Na | KCl | <10 (NMR 4) | n.a. 2 | n.a. 2 | 40 | [33] |
| Na | KCL | <80 (FRAP) | n.a. 2 | n.a. 2 | 1 | [34] |
| Na | CaCl2 | <80 (FRAP) | n.a. 2 | n.a. 2 | 0.01 | [34] |
| Na | KCl | <100 (PT) | n.a. 2 | n.a. 2 | 2 | [35] |
| Com. | KCl | 9.5 (SAXS) | n.a. 2 | 25.1 (SAXS) | 11 | [36] |
| Com. | CaCl2 | 17.7 (SAXS) | n.a. 2 | 41 (SAXS) | 130 | [36] |
| Na | KCl | n.a. 2 | <200 (AFM 3) | 1.5–2 (AFM) | 2 | [16] |
| Na | CaCl2 | n.a. 2 | <500 (AFM 3) | 1–1.5 (AFM) | 0.2 | [16] |
1 Com.: commercial carrageenan used as received; Na: sodium form; K: potassium form; Ca: calcium form. 2 n.a.: non available. 3 Estimates from pictures reported in the corresponding reference. 4 Estimate from the hydrodynamic radius of the polymer probe used in NMR.