Table 1.
Main characteristics of aerogels, cryogels and xerogels, respectively.
| Characterization | Polysaccharide | Aerogel | Cryogel | Xerogel | Reference |
|---|---|---|---|---|---|
| Bulk density (g/cm3) | Pectin | ~0.083 | ~0.073 | ~1.057 | [9] |
| Pectin/TiO2 | 0.11–0.24 | N/A | N/A | [67] | |
| Chitosan | 0.07–0.26 | 0.03–0.12 | ~1.30 | [62] | |
| Chitosan/xantan gum | 0.24–0.36 | 0.099 | N/A | [68] | |
| Volume shrinkage (%) | Pectin | ~30 | f10–13 | 90 | [9] |
| Chitosan | ~20 | ~0 | ~80 | [62] | |
| Cellulose | ~8.5–19.2 | ~41 | ~89–93.4 | [29] | |
| Porosity (%) | Pectin | ~94 | ~95 | ~30 | [9] |
| Chitosan | 80–95 | 90–98 | ~10 | [62] | |
| Cellulose | ~92.7–96 | 94.3 | 70.2–80.3 | [29] | |
| Chitosan/xantan gum | ~60–68 | ~85 | [68] | ||
| BET specific surface area (m2/g) | Pectin | ~362 | 10–20 | N/A | [9] |
| Pectin/TiO2 | 339–461 | N/A | N/A | [67] | |
| Chitosan | 200–270 | 50–70 | N/A | [62] | |
| Chitosan/xantan gum | ~5.7–17.5 | ~9.1 | N/A | [68] | |
| Cellulose | 287–303 | 23 | 0.81–107 | [29] | |
| Corn starch | ~64 | N/A | N/A | [69] | |
| Network morphological aspect (according to scanning electron microscopy, SEM) | Pectin | Mesopores and small macropores (50–150 nm in diameter) | Large macropores (0.5–5 µm in diameter) | Dense network | [9] |
| Pectin/TiO2 | Macropores >50 nm Mesopores (2–50 nm) Micropores (<2 nm) |
N/A | N/A | [67] | |
| Chitosan | Size of pores of about ~0.25 µm |
Largest pores (~0.5 µm) | Absence of pores | [62] | |
| Cellulose | Mezopore size distribution between 5–200 nm | Nanofibrils between 50–100 nm | Macropores size between 50–120 µm | [29] | |
| Chitosan/xantan gum | Dense and smooth surface | Granular-like structure and rough surface | N/A | [68] |