Food thickeners are used to produce thickness and consistency in liquid food items.  Thickeners are also used in cosmetics and body care items such as shampoos and conditioners, but this lesson will focus on thickeners used in food and sold in most natural product stores.  Thickeners used in packaged grocery items are covered in advanced lessons.

Food thickeners are typically based on polysaccharides (starches, vegetable gums, and pectin), or proteins.  Starches include arrowroot, cornstarch, katakuri starch, potato starch, sago, tapioca and their various derivatives. Vegetable gums used as food thickeners include guar gum, locust bean gum, and xanthan gum.  Proteins used as food thickeners include collagen, egg whites, and gelatin.  Sugars include agar and carrageenan.  Other thickening agents act on the proteins already present in a food, such as sodium pyrophosphate, which acts on casein in milk during the preparation of instant pudding.

Starch thickeners are the type used in most households.  But the choice of thickeners used in cooking depends on differences in taste, clarity, and their responses to chemical and physical conditions.  For example, arrowroot is a better choice than cornstarch for acidic foods because it loses thickening potency in acidic mixtures.   At pH levels below 4.5, guar gum has sharply reduced thickening capability.  If the food is to be frozen, tapioca or arrowroot is preferable over cornstarch, which becomes spongy when frozen.  Prolonged cooking and stirring as well as exposure to acids like lemon juice, wine, and vinegar weaken all starches’ thickening power. Different starches, however, can endure different amounts of heat, agitation, and acidity before they start to break down and lose their thickening power.

The most common thickeners sold to consumers in natural product stores are these:

Agar (often referred to as Agar Agar) is a traditional odorless, tasteless sea vegetable gelatin created by a long, slow process that combines a mixture of red algae sea vegetables of the Gelidium and Gracilaria species.    After harvesting, the seaweed is washed, sun-bleached, strained, and allowed to harden and dry. Through this process it is transformed into odorless light-weight translucent bars, shaved into fine flakes, or powdered.   Agar is rich in iodine, calcium, iron, and other trace minerals.  It is most often used in desserts, a thickener for soups, fruit preserves, ice cream and as a clarifying agent in brewing.  It is also an important vegetarian substitute for gelatin, an animal product, and is also important in macrobiotic cooking.  Some health food stores may merchandise it in the macrobiotic section of the store.  Agar doesn't perform as well in acidic liquids so more is needed to achieve a jello-like texture.  Nor does it do well in recipes with milks or other fatty ingredients which make agar difficult to dissolve.   Medicinally, agar can also act as a mild laxative by adding bulk in the body. The seaweed thickener is mostly an indigestible complex carbohydrate that passes through the body unchanged; however, it bonds with toxic and radioactive pollutants and helps to expel them from the body.

Arrowroot is an easily digested, less processed, starch extracted from the roots of the arrowroot plant, Maranta arundinacea. Gluten-free, the starch is used as a thickener in many foods such as puddings and sauces, and is also used in cookies and other baked goods.  It helps make cakes and cookies lighter and softer.  It has about twice the thickening power of flour.  Unlike cornstarch, arrowroot is completely flavorless and will not impart a starchy taste into puddings or other dishes.  It does not turn sauces cloudy and works best at temperatures below simmer.  It has a neutral taste and tolerates acidic ingredients.  It will freeze well and dissolves at lower temperatures, but does not perform well in milk-based cream sauces. 

Why This Matters:

Arrowroot is simply dried and ground root. Corn starch is made by wet milling, a process which requires at least 6 steps. In addition to being more processed, corn starch is also highly at risk for GMO’s, although organic varieties are available.

Cornstarch (gluten-free) is one of the most common thickeners typically used in soups, stews, sauces and gravies.   Made from corn, it has twice the thickening power of flour, but can produce a slightly starchy taste.  Made through a series of mechanical processing steps, it is highly refined and has little nutritional value.  Customers who want to avoid GMOs in corn products should look for organic corn starch.  Corn starch may be added to rice flour (also considered a natural thickener) for certain sauces and gravies.  Cornstarch is the best choice for dairy based sauces, but sauces made with cornstarch do not freeze well, instead turning spongy.  Cornstarch performance can disappoint if the cook uses too little liquid, too much sugar, too  much fat or too much acid; or if there is too much stirring, excessive cooking, or undercooking.  Cooks should make sure they use a clean spoon to taste a corn starch thickened sauce.  If one is not used, the digestive enzymes in a person's mouth will cause a properly thickened mixture to thin dramatically in a few minutes.

Eggs provide excellent natural thickeners for some dishes by using the yolks.  They are classically used in Hollandaise sauce and its derivatives, mayonnaise, Aioli, puddings, ice creams, pastry creams, and custards.  Egg yolks provide both a rich flavor and a velvety smooth texture, but they need to be handled carefully to achieve the thickening result.  If they are added to a hot sauce, they will curdle on contact.  Instead, they need to be "tempered" by adding a small amount of the hot liquid to the egg yolks, whisking the mixture together, then adding the mixture to the sauce slowly, whisking all the while.  Egg yolk sauces should never be cooked in an aluminum pan because the chemistry between the aluminum and the yolks will turn the sauce a gray color. 

Flour made from wheat is a good thickener for pie fillings, gravies, gumbos, and stews.  Typically, unbleached white flour is made into a roux by combining equal parts flour and a fat - butter or meat drippings - and whisked and cooked over heat to ameliorate the flavor of the flour and remove lumps.  Liquids are then added and the resulting sauce or dish begins to thicken between 144°F and 162°F. and complete the process at 205°F.    

Fruit Pectin is a naturally occurring polysaccharide found in berries, apples and other fruit.  When heated together with sugar, it causes a thickening that is characteristic of jams and jellies.  Prepared pectin is a white powdery substance that has been produced by extracting the polysaccharides from apples and adding citric acid and dextrose as binders.  It doesn't add or change the flavor of foods and allows the home cook to use less sugar and prepare thickened recipes more quickly.  Pectin is used most often in jams, jellies, marmalade and jelled fruit desserts.  Because it gives a good gel structure, a clean bite, and confers a good flavor release, it is sometimes used as a stabilizer in protein drinks, or drinking yogurt to improve mouth-feel.  Pectin is also used in medicine.   Pectin has a limited shelf life so store staff who manage this product need to be aware of expiration dates and product rotation.

Gelatin is a translucent, flavorless gelling agent derived from collagen, a natural protein present in the tendons, ligaments, and tissues of mammals.  It is produced by boiling the connective tissues, bones, and skins of animals, usually cows and pigs.   Gelatin's ability to form strong, transparent gels and flexible films that are easily digested, soluble in hot water, and capable of forming a positive binding action have made it a valuable commodity in food processing, pharmaceuticals, photography, and paper production.  Most consumers consume gelatin in the form of a flavored dessert, but unflavored gelatin is also used as a binding ingredient in savory and sweet recipes, such as aspic. 

Why This Matters:

Gelatin is NOT vegetarian or vegan friendly and because of how it is manufactured, many natural food stores do not carry traditional gelatin.  Depending on the customers’ purpose, agar or a Vegan Jel made from vegetable gum could be recommended as a substitute.

Kudzu (also known as Kuzu) is a starch extracted from the deep roots of the kudzu vine.  It is dried and is available as a white powder or in chalky lumps.  Like cornstarch and arrowroot, kudzu is used as a thickener in sauces, gravies, stews and deserts.  It is also used as a gelling agent like agar and gelatin.  It is considered a macrobiotic staple and often will be merchandised in the macrobiotic area of the store alongside Agar.  It should be dissolved in cold liquid before adding to the pot, and then stirred constantly until the milky white color is eliminated and becomes clear.  Kudzu has high iron content, plus fair amounts of calcium and phosphorus.

Why This Matters:

Both agar and kudzu have “gelling” properties. With a little experimenting, your customer can find what works best in a particular recipe.

Potato Starch is most frequently used for sauces, soups, and stews.  It tolerates higher temperatures than cornstarch and is a natural way to add moistness to many baked goods.  Gluten-free potato starch is 100% starch, whereas potato flour is 85% starch, the rest being fiber, fat, protein and sugar.  Potato starch will turn clear in a recipe, versus potato flour, which turns to opaque.  It is also an approved thickener for Passover, a time when cornstarch is not permitted.  Most packages will include a Kosher seal.  

Tapioca is the starch extracted from the root of the cassava plant, also called manioc or yuca.  It comes in various forms including pearl (also known as pellet or bead), flour (not wheat), and the tiny-grained instant or quick are the three types most common.  Pearl tapioca, which comes in various sizes, is used almost exclusively to make tapioca pudding, lending body and texture.  The pearls need to be hydrated after which they become translucent, slightly swollen, and jelly-like. Tapioca flour (finely ground tapioca - it does not contain wheat) is sometimes used in restaurants for soups, fruit fillings and glazes.  It is sometimes called tapioca starch and can be substituted for cornstarch in some recipes.

Xanthan Gum is a corn-based, fermented product that is used as a thickener, particularly in gluten-free foods.  People who are sensitive to corn should avoid xanthan gum and use guar gum instead.  Xanthan gum is a polysaccharide, created when the bacteria, xanthomonas campestris, is allowed to ferment on sugar.  The result is a gel that is dried and powdered.  It operates both as an emulsifier as well as a thickener, and can create a creamy texture.  In gluten free baking, xanthan gum serves a similar purpose as gluten, making the dough elastic and able to rise and hold shape during baking.  It can also be found in salad dressings, sauces, and ice cream.  It can be found in natural product stores in one-pound packages or in smaller 6 ounce. packages.

Why This Matters:

Xanthan gum is commonly made from corn, but can also be made from wheat or soy. While the final product only contains trace amounts of these ingredients, people with severe wheat, gluten, or soy allergies can have issues with Xanthan gum.

Leaveners

Sometimes referred to as rising agents, leavening agents are substances that produce gases which are then incorporated into dough or batters, causing the finished item to rise and increase in volume.  These rising agents are typically merchandised in the same area of the natural food store as the thickeners or in the baking aisle.  There are chemical leaveners such as baking soda and baking powder, along with other leaveners including yeast, baker's ammonia and cream of tartar that are considered natural.  Natural product stores will typically carry baking soda and powder even though purists would not classify these items as natural.  Different leaveners also can contribute to the taste of different baked item, especially yeast items.

Baking Powder is a blend of acid, usually calcium acid phosphate, sodium aluminum sulfate or cream of tartar) and baking soda, which is alkali.  When moistened and heated, the baking powder produces carbon dioxide bubbles which act as a filler in the recipe.  Experts recommend looking for baking powder that does NOT contain aluminum ingredients. 

Baking Soda creates carbon dioxide gas when moistened.  Double-acting baking powder, the most popular on the market today, produces an initial set of gas bubbles when mixed with wet ingredients and a second set when heated.  The results are lighter items with fine textures.  This leavener is most typically used in recipes with acid ingredients such as applesauce, soured milk, buttermilk, honey, brown sugar, molasses, cream of tartar, lemon juice or vinegar, chocolate and cocoa powder.  Baking soda is four times as strong as baking powder. The general rule is to use 1 to 1-1/4 teaspoons baking powder per cup of flour. On the other hand, baking soda should be added at 1/4 teaspoon per cup of flour.

Baker's Ammonia is a type of baking powder that yields a very light, airy product, but can impart an ammonia flavor to baked goods.  It's best used in cookies, which are flat enough to allow all of the ammonia odor to dissipate during cooking. Northern Europeans still use it because it makes their Springerle and gingerbread cookies very light and crisp.

Why This Matters:

Bakers Ammonia is NOT ordinary household ammonia, which is poisonous.

Cream of Tartar is made from the acidic sediment that develops on the side of wine caskets.  It is particularly useful in its dry white powdered form and is used in recipes for cookies, cakes and old recipes created before commercial baking powder was a staple in the market. It used to give a creamier texture to sugary things like candy and frosting and to stabilize and increase the volume of beaten egg whites, often used during whipping.  It may also be used in candy-making because its acidity affects sugar as it cooks, preventing unwanted crystallization resulting in a creamier texture. 

Vital Wheat Gluten (see Lesson 4 Topic 1) is the protein found in wheat.  When added to yeast bread, it improves the elasticity of the dough and helps to produce light textured bread.  It can also be used to make seitan.

Yeast is a microscopic, unicellular fungus that is the necessary and vital component of bread making, as well as the making of wine and beer.  There are more than 1,500 known species of yeast.  Typically, natural food stores will carry fresh yeast known as Active Dry Yeast or Yeast Cake.  There are other types for sourdough bread, often called pre-ferments and sourdough starters.   All yeast goes through a process of fermentation, which is responsible for leavening the dough, creating the texture, and maturing the gluten from the flour.   In order to function properly, all yeast needs food, moisture and a warm environment.   Yeast is sensitive – too much heat or cold, will kill it; too much or too little salt will hinder the fermentation and if added at the wrong time will kill the yeast.

 

 

Words to Remember

AIOLI

A spread from the French region of Provence that combines garlic, egg yolk, lemon juice, mustard and olive oil that resembles mayonnaise.

 

GELATIN

A virtually colorless and tasteless water-soluble protein prepared from collagen and used in food preparation as the basis of jellies, in photographic processes, and in glue.

 

KATAKURI STARCH

A thickener made from the katakuri lily native to Japan and used in Japanese cooking from soups to fried tempura.

 

POLYSACCHARIDE

Carbohydrates made up of many monosaccharides joined together.