Hydrocolloide

Hydrocolloide refers to water-loving polymers that form colloidal dispersions in water and, under certain conditions, gels. They are typically high‑molecular‑weight natural or synthetic polymers, including polysaccharides and proteins, that hydrate and swell when dispersed in water. Gel formation can be physical or chemical, driven by hydration, cooling, ionic crosslinking, or pH changes.

Common hydrocolloids include gelatin, agar, carrageenan, alginate, xanthan gum, guar gum, pectin, starch, and cellulose derivatives. They may act as thickeners, stabilizers, emulsifiers, or gelling agents, and their properties depend on molecular weight, concentration, temperature, pH, and ionic strength. Some form gels upon cooling (gelatin), others through ionic crosslinking with multivalent cations (alginate with calcium).

Applications span food, pharmaceuticals, cosmetics, and medicine. In food, they create textures, stabilize emulsions, and control water activity. In pharmaceuticals, they serve as excipients, thickeners, and controlled-release matrices. In wound care, hydrocolloid dressings absorb exudate and form a moist gel that protects the wound. In dentistry, alginate-based hydrocolloid impressions are used to capture dental arches.

Safety and regulation vary by substance and jurisdiction; many hydrocolloids are approved for specific uses, and some may cause allergies or sensitivities in rare cases. They are selected to achieve desired rheological and sensory properties in the final product.