Hydrocolloids

Perhaps the most important family of these new (and not so new) thickeners consists of hydrocolloids. Technically, a hydrocolloid is anything that disperses particles in water. Even though some hydrocolloids are starches or very similar to starches, when chefs refer to hydrocolloids, they’re talking about substances that form long chains of polymers (usually of simple sugars, but sometimes amino acids). These polymers interfere with the fluidity of water and render a sauce thicker. Many hydrocolloids also act as emulsifiers and hence thicken—or at least keep from breaking—sauces such as hollandaise or mayonnaise. Hydrocolloids can also cause liquids to gel, a useful characteristic when making chauds-froids and gelées. For a list of hydrocolloids.