Hydrocolloids

Hydrocolloids are high-molecular-weight polymers that readily interact with water to form viscous solutions, gels, or suspensions. They are used to modify the texture, stability, moisture retention, and mouthfeel of foods, pharmaceuticals, cosmetics, and industrial products. Hydrocolloids can be natural, semi-synthetic, or synthetic and include polysaccharides and some proteins.

Common natural hydrocolloids include plant-derived gums such as guar gum, locust bean gum, xanthan gum, carrageenan, alginates, pectin, and starch derivatives; animal-derived gelatin; and seaweed extracts like agar. Synthetic examples include carboxymethylcellulose and hydroxyethylcellulose. These polymers differ in molecular weight, charge, and solubility, which influence their gelling abilities and response to salt, pH, and temperature.

Most hydrocolloids act by forming a network that traps water. Some are thickening agents that increase viscosity without forming a gel, others form gels that can be thermoreversible (gelatin, agar) or thermally irreversible. The functionality depends on concentration, ionic strength, pH, and temperature.

Applications span the food industry (thickening, stabilizing emulsions, gelation for textures), pharmaceuticals and nutraceuticals (excipients, controlled release, tablet disintegration), cosmetics (texture and moisture retention), and industrial uses (drilling fluids, paper coatings). Safety and regulatory status vary by compound and jurisdiction; many hydrocolloids have GRAS status in the United States but may require labeling or usage limits. Careful selection is needed to achieve desired rheology and ensure compatibility with other ingredients.