Hydrocolloid

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A hydrocolloid is defined as a colloid system where the colloid particles are dispersed in water. A colloid system is simply a system or mixture in which two substances are interspersed between each other. A hydrocolloid has colloid particles spread throughout water and depending on the quantity of water available can take on different states, e.g: gel or sol (liquid). Hydrocolloids can be either irreversible (single state) or reversible. For example, agar, a reversible hydrocolloid of seaweed extract, can exist in a gel and sol state and alternate between states with the addition or elimiation of heat.

Many hydrocolloids are derived from natural sources. For example, carrageenan is extracted from seaweed, gelatin has bovine (cow) and fish origins and pectin extracted from citrus peel and apple pomace.

Jell-O (trade mark Jell-O), the well known dessert, is made from gelatin powder, another effective hydrocolloid. Hydrocolloids are employed in food mainly to influence texture or viscosity (ex. of a sauce). Hydrocolloids are also used in skin care and wound dressing.