Thickening agent
Thickening agents are often regulated as food additives and as cosmetics and personal hygiene product ingredients.
A flavorless powdered starch used for this purpose is a fecula (from the Latin faecula, diminutive of faex, "dregs").
Typical gelling agents are based on polysaccharides such as natural gums, starches, pectins and agar-agar or proteins such as gelatin.
Examples are: Commercial jellies used in East Asian cuisines include the glucomannan polysaccharide gum used to make "lychee cups" from the konjac plants, and bbl aiyu or ice jelly from the Ficus pumila climbing fig plant.
Kappa carrageenan may include potassium chloride to improve the gelling process and produces a clear product with very little aftertaste.
The most basic type of thickening agent, flour blended with water to make a paste, is called whitewash.
Roux, a mixture of flour and fat (usually butter) cooked into a paste, is used for gravies, sauces and stews.
Overheating easily ruins such a sauce, which can make egg yolk difficult to use as a thickener for amateur cooks.
Other thickeners used by cooks are nuts (including rehan) or glaces made of meat or fish.
As an alternative to adding more thickener, recipes may call for reduction of the food's water content by lengthy simmering.
When cooking, it is generally better to add thickener cautiously; if over-thickened, more water may be added but loss of flavour and texture may result.
Fumed silica and similar products form stiff microscopic chains or fibers which interlock or agglomerate into a mass, holding the associated liquid by surface tension, but which can separate or slide when sufficient force is applied.
Additives such as precipitated silica, fine talc, or chalk also meet the definition of thickening agent in that they increase viscosity and body while not affecting the target property of a mixture.
[citation needed] Thickening agents used in cosmetics or personal hygiene products include viscous liquids such as polyethylene glycol, synthetic polymers such as carbomer (a trade name for polyacrylic acid) and vegetable gums.
[citation needed] One of the main use of thickeners is in the paint and printing industries, which depend heavily on rheology modifiers, to prevent pigments settling to the bottom of the can, yielding inconsistent results.
Water based formulas would be nearly impossible with the exception of India ink and the few other water-soluble pigments, but these would have very little coverage and at best would stain wood slightly.
