hydrocolloïd

A hydrocolloid is a substance that forms a gel or a viscous solution when dispersed in water. It is typically a hydrophilic polymer that swells and creates a three‑dimensional network capable of trapping significant amounts of water, thereby thickening liquids or forming gels.

Hydrocolloids arise from natural sources such as seaweed, plants, and animal products, as well as from synthetic or semi‑synthetic polymers. Common natural hydrocolloids include agar, carrageenan, alginates, pectin, guar gum, xanthan gum, and starch; gelatin comes from animal collagen. Their gelling behavior varies, with some forming thermo‑reversible gels and others producing more permanent networks, depending on factors like temperature, pH, and ion content.

The primary functions of hydrocolloids are thickening, gelling, stabilizing emulsions, and suspending particles. They also control water activity, modify texture, and can act as edible coatings. In addition to texture modification, some hydrocolloids influence moisture retention, viscosity at low shear, and the rheological properties of mixtures, which are important in production and sensory perception.

Applications span multiple industries. In food, hydrocolloids are used as thickeners and gellants in sauces, dairy products, desserts, meat products, and bakery items, as well as in beverages and confectionery. In pharmaceuticals and cosmetics, they serve as binders, suspending agents, and controlled‑release components. In wound care, hydrocolloid dressings form gels upon exudate contact to maintain a moist healing environment.

Safety and regulation vary by substance and intended use. Most hydrocolloids are considered safe when used as directed, but some, like gelatin, may raise dietary or allergy concerns. Proper labeling and adherence to regional food and medical regulations are important.