Thickening agents

Thickening agents, or thickeners, are substances which,

when added to an aqueous mixture, increase its viscosity without

substantially modifying its other properties, such as taste. They

provide body, increase stability, and improve suspending action.

They also improve the nutritive value. Thickening agents are often

food additives.

Food thickeners are frequently based on polysaccharides

(starches or vegetable gums) or proteins (egg yolks, demi-glaces, or

collagen). Common examples are agar, arrowroot, coconut,

tamarind, curd, poppy seeds, onion taste, coriander powder, gelatin,

katakuri, pectin, rehan, roux, tapioca, guar gum, locust bean gum,

and xanthan gum. Flour is often used for thickening gravies, gumbos

and stews. It must be cooked in thoroughly to avoid the taint of

uncooked flour. Cereal grains (oatmeal, couscous, farina, etc.) are

used to thicken soups.

Some of the thickening agents are discussed below:

Roux

Roux (pronunced ROO) is a thickener that's made from equal

weights of flour and a fat, like butter or meat drippings. It is

especially good for thickening rich, hearty stews and gravies. Some

popular types of roux are:

§ White roux - Melt the butter, add the flour and cook for a

few minutes over a low heat while stirring constantly.

§ Blond roux - It is made in the same manner as the white

roux but it is cooked a little longer. It is finished when the

flour has a blond colour.

§ Brown roux - It is made in the same manner as the blond

roux but it is cooked until the flour has a very distinct light

brown colour and nutty aroma.

Beurremanie

Beurremanie (pronounced BARE mahn-YAY) is flour-butter

mixture. It is used to correct overly thin sauces at the last minute. To

make it, blend equal weights of butter and flour is mixed and knead

together. After whisking it into a sauce, it is cooked for no more than

a minute or two, since sauces thickened with flour pick up a starchy

taste after they've cooked for a few minutes. Beurremanie is mainly

used in "a la minute" cookery.

Fresh Cream

Fresh cream is generally used to finish sauces and soups, It

has also a slight thickening effect.

Egg Yolks

Egg yolks make wonderful thickeners--imparting both a rich

flavor and velvety smooth texture. We need to "temper" them by

adding some of the hot liquid to the egg yolks, whisking the mixture

together, and then adding it to the sauce.

Pectin

Pectin (pronounced PECK-tin) is a white to light brown

powder derived from the cell wall of higher terrestrial plants. It is

mainly used in food as a gelling agent in jams and jellies. Some fruits

like quinces, gooseberries, tart apples, and sour plums, contain

enough natural pectin that they'll thicken all by themselves into

preserves. Others, like cherries and some berries, need an extra

boost to firm up. Jam recipes for pectin-deficient fruit normally call for

liquid or powdered pectin.

Liaison (Fresh Cream and Egg Yolks)

Liaison is a very popular thickening agent in white sauces

and cream soups. A Liaison consists usually of 2/3 cream and 1/3

egg yolk (1 dl.cream and 1 egg yolk). The soup or sauce containing

liaison is not allowed to boil .

Refined Flours and Starches

These are products such as arrowroot, cornflour, fecule etc.

They are diluted with water, milk, wine or stock, then stirred into the

boiling liquid and allowed to boil for a few minutes. The thickening

power of these products is usually stronger than the one of ordinary

flour, therefore these products are used in small quantities only.

Arrowroot

Arrowroot has a neutral taste and thickens at a lower

temperature than corn starch, and hence can be used to thicken

delicate egg-based soups and sauces. It also imparts an eyepleasing

glossy look to the sauce. However, care needs to be

exercised not to add arrowroot too early during the cooking process,

as overheating tends to destroy its thickening property.