Thickening & Binding Agents

Thickening Agents give body, consistency and potability when used, when used. They improve the nutritive value. Flavored liquids are thickened and converted into soups, sauces, curries, mousses, puddings, etc. 

Binding Agents are used to form a mixture of ingredients into a cohesive mass.
The thickening agents are starch, agar, eggs, gelatin, coconut, tamarind, curd, poppy seeds, onion paste, coriander power, etc. starch is the reserve carbohydrate of plants and is abundant in common food: corn, rice, wheat, potatoes, arrowroot, and tapioca; rice has about 80 per cent starch, wheat 70 per cent and potatoes about 19 per cent starch. 

Starch is classified into cereal starches, root starches and instant starches.

Cereal starch is found in rice, wheat and maize. (Thickening And Binding Agents )

When cooked, corn wheat, or rice, begins to gelatinize at about 710c (160oF) but requires about 85-96oc (185-205oF) for maximum thickening. Cereal starches, when cooked and cooled, tend gel, while most root starches do not, as they have more thickening power than root starches. Root starches. Thicken at a lower temperature of 65-71oc (150-160oF) than cereal starches. They thicken completely below boiling point. Instant starches are pre-cooked starches, also known as pre-gelatinized starches.

 Instant puddings, etc., in the market contain instant starches. 

‘Thickening And Binding Agents’

Agar is a rigid transparent gel, and is used for salads and sweet dishes. It is a seaweed, widely found in china. 
Eggs give a firm gel when baked, and thicken, but are soft when stirred.
Gelatin (unflavored) is used for salads, cold sweets and cold soups. When set, it is transparent, firm and quivery. 
Coconut is used for curries, and gives the gravy a whitish color, and thickens and enhances the taste. 
Tamarind is used in a pulpy form and it gives a thickening to the consistency of the gravy and gives a brownish appearance and an acidic taste.
Curd is used for thickening curries and it gives a whitish appearance, and a good flavor.
Poppy seeds, onion paste, coriander powder give body to the curries, and slightly thicken the gravy and blend with the flavor of the curry. 

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Definition

Most sauces and gravies are thickened with some kind of starch. Thickening agents increase the viscosity of a liquid mix without interfering with its other properties. Each thickening agent has properties best suited for specific recipes. Starches are the most common and most useful thickeners for sauce-making. Flour is the principal starch used. Others available starches to the chef include cornstarch, arrowroot, waxy maize, instant or pre gelatinized starch, bread crumbs, and other vegetable and grain products, like potato starch and rice flour.

Roux

Roux (roo) is a cooked mixture of equal parts by weight of flour and fat such as clarified butter, margarine, shortening, animal fats, vegetable oil or rendered meat drippings.

Types of Fat Used in Making Roux

Clarified butter is preferred for the finest sauces because of its flavor. The butter is clarified because the moisture content of whole butter tends to gelatinize some of the starch and makes the roux hard to work.

Margarine is widely used in place of butter because of its lower cost. However, its flavor is inferior to butter, so it does not make as fine a sauce. The quality of margarine varies from brand to brand.

Animal fats, such as chicken fat, beef drippings, and lard, are used when their flavor is appropriate to the sauce. Thus, chicken fat can be used for chicken velouté, and beef drippings can be used for beef gravy. When properly used, animal fats can enhance the flavor of a sauce.

Vegetable oil and shortening can be used for roux but, because they add no flavor, they are not preferred. Solid shortening also has the disadvantage of having a high melting point, which gives it an unpleasant fuzzy feeling in the mouth. It is best reserved for the bakeshop and the fry kettle.

Today, roux-thickened sauces are often condemned for health reasons because of the fat content of the roux. It should be remembered, however, that when a roux-bound velouté or brown sauce is properly made, most of the fat is released and skimmed off before the sauce is served.

Types of Flour Used in Making Roux

The thickening power of flour depends, in part, on its starch content. Bread flour has less starch and more protein than cake flour. Eight parts (such as ounces or grams) of cake flour has the same thickening power as 10 parts of bread flour. Bread flour frequently is used for general cooking purposes in commercial kitchens even though it has less thickening power than cake flour or pastry flour. Most sauce recipes are based on bread flour or on all-purpose flour, which has similar thickening power. The proportions of roux to liquid must be adjusted if another flour is used.

Flour is sometimes browned dry in the oven for use in brown roux. A heavily browned flour has only one-third the thickening power of unbrowned flour. In addition to starch, wheat flour contains proteins and other components. As a roux thickened sauce is simmered, these components rise to the surface as scum. They then can be skimmed off. Sauces are generally simmered for a time even after the starch is completely gelatinized so these “impurities” can be cooked off. This improves the texture, gloss, and clarity of a sauce. When a high-protein flour such as bread flour is used in a roux, the sauce must be cooked longer and skimmed more often to achieve good clarity. Sauces made with wheat flour do not freeze well because some of the starch breaks down when frozen, reducing its thickening power.

Ingredient Proportions of Roux

Correct amounts of fat and flour i.e. equal parts by weight are important to a good roux. There must be enough fat to coat all the starch granules, but not too much. In fact, Escoffier called for even less fat than our standard proportions (8 parts fat to 9 parts flour). A good roux is stiff, not runny or pourable. A roux with too much fat is called a slack roux. Excess fat increases the cost of the roux unnecessarily; the excess fat rises to the top of the sauce, where it either is skimmed off or makes the sauce look greasy.

There are 3 stages of a roux.

White Roux

Blond Roux

Brown Roux

A white roux retains its initial color and is only cooked slightly to remove any starchiness from the roux. A blonde roux is caramelized slightly to give it a darker blonde color. A brown roux is cooked until almost burnt; highly caramelized, it also has a nice nutty flavor to it.

Beurre manié (burr mahnyay)

It is a mixture of equal parts soft, raw butter and flour worked together to form a smooth paste. It is used for quick thickening at the end of cooking to finish a sauce. The raw butter adds flavor and gives a sheen to the sauce when it melts. To use, drop very small pieces into a simmering sauce and stir with a whip until smooth. Repeat until desired consistency is reached. Simmer just a few minutes more to cook the flour, and then remove from the fire.

Liaison (lee-ay-zohn)

Is a mixture of cream and beaten egg yolks that is added to soups and sauces to improve color, increase flavor, improve texture and bind them together. The finished product must be held under 1800 F. or the eggs will curdle. For this reason a liaison is usually added at the last minute to reduce the possibility of the eggs curdling. Part of a soup or sauce is whipped into a liaison gradually until all of the mixture is incorporated. By adding a small portion of hot sauce or soup to the cold liaison, the temperature of the eggs is not increased too markedly at one time. If the 1iaison is to be added to the soup or stock, the product must be sufficiently cooled to prevent curdling of the eggs.

A rule of thumb ratio is three parts of cream to one part of eggs by weight. Weight measurement is more accurate than volume. As this form of liaison is expensive, its use is prohibitive in many operations. It is used primarily in establishments where menu prices are above average and most items are cooked to order.

To incorporate liaison:

Remove sauce from heat.

Correct seasoning and strain if necessary.

Combine beaten egg yolks and cream.

Whip small amounts of sauce into liaison gradually until certain that eggs will not curdle.

Incorporate liaison-sauce mixture with balance of sauce.

Hold for service.

Whitewash

It is a thin mixture of flour and cold water. Sauces made with whitewash have neither as good a flavor nor as fine a texture as those made with roux. Whitewash is not recommended for use.

Cornstarch

This produces a sauce that is almost clear, with a glossy texture. To use, mix with cold water or other cold liquid until smooth. Stir into the hot liquid. Bring to a boil and simmer until the liquid turns clear and there is no starchy taste. Do not boil for a long period or the starch may break down and the liquid become thin. Sauces thickened with cornstarch may thin out if held on the steam table for long periods. Cornstarch is used extensively in sweet sauces to accompany certain meats as well as in desserts and dessert sauces. It has roughly twice the thickening power of flour.

Arrowroot

It is used like cornstarch, but it gives an even clearer sauce. Its use is limited by its high cost. Nevertheless, because of its quality, it is the preferred starch for thickening jus lié. It is less likely than cornstarch to break down when heated for a long time. Most commonly added as a slurry, and its full thickening power is not realized until the sauce is brought to a simmer.

Slurry

The easiest and quickest thickening method, a slurry thickens almost immediately and creates a glossy appearance. To create a slurry, corn starch is stirred into a small amount of cold water or stock, then whisked into a simmering sauce.

Waxy Maize

It is used for sauces that are to be frozen. Flour and other starches break down and lose their thickening power when frozen. Waxy maize does not. It is handled like cornstarch.

Pregelatinized or Instant Starches

This have been cooked, or gelatinized, and then re-dried. Thus, they can thicken a cold liquid without heating. These starches are rarely used in sauce-making but are frequently used in the bakeshop.

Bread Crumbs

Bread crumb and other crumbs will thicken a liquid quickly because they have already been cooked, like instant starches. Bread crumbs may be used when smoothness of texture is not desired. A common example is the use of gingersnap crumbs to thicken sauerbraten gravy.

Vegetable Purées

A simple tomato sauce is basically a seasoned vegetable purée. The sauce gets its texture from the thickness of the main ingredient. No additional thickener is needed. Using this same principle, we can add body or texture to sauces by adding a smooth vegetable purée, or by puréeing mirepoix or other vegetables with the sauce.

Nuts & Seeds

Finely grounded Nuts and seed such as ground nut, cashew nut, pumpkin seed or chaar magaz are used in making of soup which adds texture as well as flavor to a sauce.

Chaar Magaz

Four seeds i.e. pumpkin seeds, water melon seeds, musk melon seeds & cucumber seeds together are known as char magaz in Hindi & many Indian languages. The paste of this used as thickening in many Indian gravies.

Fecule (Potato Starch)

Raw Potatoes are sometimes used as a thickening agent in puree soups and are cooked with legumes. The starch from the potatoes is the major thickening factor. Potato starch settles to the bottom of a soup crock if it stands for long periods of time. A small amount of roux is often added to prevent this separation.

Farine

Literally the French word for “flour”. As a thickening technique it refers to dusting your product (usually a protein) in flour. The excess flour is then shaken off, and the product is sautéed. The pan is then usually de-glazed, and a sauce is built on top of this base. Also commonly used to build a base for thick soups and stews.

Panada

Most commonly used to stabilize and bind meat balls and pâtés, it is usually a mixture of day old bread and some sort of liquid; stock, milk, water, etc. In the case of thickening sauces or soups, the bread is usually browned in butter and then simmered into the base that you wish to thicken. It can either be left as is, or blended and strained for a more refined consistency. It aids in binding the fat. It also lightens the density of the product. It contributes to the seasoning of the product. Some examples of panada is below

Bread Panada

Flour Panada

Frangipane Panada

Rice Panada

Potato Panada

Food Grade Gums

Food grade gums are really emerging as the thickening agent of choice in a lot of high end kitchens. They’re gaining popularity because they are extremely neutral in flavor and are added in such low concentrations (usually less than 0.5% by weight), that they have no effect on color or flavor. One of the most commonly used food grade gums for this purpose is Xanthan Gum, which can be picked up at a lot of health foods stores.

Tapioca Granules

These translucent, pearly granules have a thickening power slightly greater than corn starch. They are commonly used to thicken pie fillings, and can also be used for creamy puddings, custards, and thickening soups and gravies. Tapioca starch thickens quickly, and at a relatively low temperature. It's a good choice if you want to correct a sauce just before serving it.

Cream

A handy and rich addition to soups because its proteins have been greatly diluted by fat globules and are less likely to form a skin (like milk does) when heated or boiled. It is also fairly immune to curdling in the presence of acidic or salty foods.

The word "cream" comes from the Greek "Chriein," which means "to anoint." This word is also the root word of "Christ," the "Anointed One."

Evaporated milk

Mary Bruce of Brunswick, Maine, cites this as a good and healthy substitute for cream as a soup thickener, adding body and helping to avoid curdling. She credits Marjorie Standish, author of Cooking Down East with the idea.

Yoghurt

A reasonably good thickener for certain soups especially Middle Eastern and south Indian recipes, it gives a tangy taste to the gravies.

Note that yoghurt has an undeservedly high reputation in health-food circles. At the turn of the 20th century, it was discovered that the growth of harmful microbes was suppressed in cows by the lactobacilli (found in yoghurt) populating their intestines. An assumption was made but, unfortunately, lactobacillus bulgaricus does not survive in humans.

Thickening Gums

One of the types of food thickeners are gums. All gums are polysaccharides, that is similar to sugars but with many sugar units making up a large molecule. They are bland in taste, odor less and tasteless. They may have a nutritional quality besides the primary function but they certainly help in digestion and may be used as laxatives too. Vegetable gums used as food thickeners include alginin, guar gum, locust bean gum, and xanthan gum.

Vegetable Gums

Vegetable gums come from the varied sources that can be on land or in sea. Some of the seaweeds are the excellent sources of food gums in which comes the carrageenan and alginates. Whereas guar, locust bean gum, pectin are obtained from the plants. Xanthan gum is obtained by the process of microbial fermentation. The source of gelatin is animal tissue.

As per the definition from vegetable gums are the polysaccharides that have the natural origin and used to increase the viscosity of the solution or food even if used in a very small concentration. So vegetable gums are actually the food thickening agents.

Major Vegetable Gums

Xanthan Vegetable Gum

Agar Agar

Cellulose Gum

Guar Gum

Locust Bean Gum

Pectin

Agar Agar

Agar agar is used as a vegetable gum for gelling the dairy products like yogurt. Agar agar as a food thickener has the capacity to absorb 100 times more water than its weight. Agar agar is a polysaccharide that has the repeating unit of alpha-D-galactopyranosyl and 3, 6-anhydro-alpha-L-glactopyranosyl.

Cellulose Gum

Use of cellulose gum as a vegetable gum and food thickening agent is not new. At home homemakers have been using it for the last 50 years. All cellulose vegetable gums are water soluble because of the cellulose content in it. It is used in ice-creams, beverages and in baked food products to prevent stalling. Also the ice-crystal formulation in ice-creams is prevented by this vegetable gum.

Xanthan Gum

Xanthan Gum is again a polysaccharide and chiefly used in salad dressing and sauces. Also some of the bakery filling use the Xanthan gum that is an excellent food thickener. This vegetable gum is also used to increase the shelf period of eatables.

Guar Gum

Guar Gum is a carbohydrate based vegetable gum and food thickener that swell up in cold water. It is an excellent food thickening agent used in food industry as it has about 80-85% of soluble dietary fibers. Because of this reason guar gum is also used in bread to have more soluble dietary content.

Locust Bean Gum

Locust Bean Gum is also called the Carob bean gum as it is made from the carob bean's seed. It is mainly used in food for water binding, thickening and gel strengthening. This vegetable gum is used as dessert gel, dairy applications and as processed cream cheese.

Pectin

Pectin is a kind of polysaccharide that is obtained from plant such as citrus fruit peel, apple peel etc. Pectin is a vegetable gum and food thickener that is used to make gel. You will find in almost every fruit based product such as jam, confectioneries, fruit drinks etc. Apart from this yogurt and other dairy products also use this vegetable gum as food thickener.