Description
Hydrogel edible coatings are thin films formed by ionic cross‑linking of polysaccharides with divalent cations, providing a moisture barrier for fresh produce.
Technical
Polysaccharides such as sodium alginate or carrageenan are cross‑linked by calcium ions to form a hydrogel network. The gelation occurs rapidly (2–5 min) at 20–25 °C, and plasticizers like glycerol (5–10 wt %) lower the glass transition temperature, yielding flexible films that remain stable from 4–25 °C. Drying at 40–50 °C for 10–15 min removes excess moisture, creating a semi‑permeable barrier that reduces weight loss of fresh fruit.
Science
Primary Reaction
Ionic cross‑linking of alginate/carrageenan with Ca²⁺ to form a hydrogel network
Sensory Profile
Aroma ()
neutralmildslightly sweetcleansubtlefresh
Origin & History
Civilization