Ingredient Information

Function

Corn starch is a thickening agent that is used in baking and in processed foods, such as, sauces, gravies, soups, and custards. It is added to salad dressings to stabilize the food emulsion. It is an ingredient in pasta. Obtained from the endosperm of the corn kernel, corn starch is a polysaccharide, consisting of repeating glucose molecules. When starch is added to water, with the addition of heat, the starch molecule swell and forms a matrix. This property, when added to food formulations, allows for the formation of thick, gel-like substances. The gels formed by starch are fairly stable, thus it is acceptable for use in foods that will be re-heated to foods that are refrigerated or frozen.

Starch can be modified enzymatically and/or chemically to produce the desired functional food properties. For example, starch can be enzymatically broken down to smaller glucose chains to produce a thinner gel or sauce. Starch that has been modified will appear on the label as “modified corn starch”.

Other Use and Industries

Although food historians have determined that starches have been used for centuries in many native cultures, corn starch is used extensively in the papermaking process. It is used as a glue or paper adhesive. Corn starch is also used industrially in the textile and laundry industries to make stain resistant fabrics. In the construction industry, start in used to make wall boards and other building materials. Today, corn starch is used as a biodegradable polymer in the manufacture of plastics and plastic bags. Using starch in this way has provided a significant reduction in non-biodegradable landfill volume.

In the pharmaceutical industry, corn starch is used as an excipient and aids in the delivery of various medicines. Cosmetically, it is favored as an alternative to talc powder due to a reduced risk of respiratory irritation. The ethanol industry has produced a great demand for corn and the food industry is feeling this competitive pressure. Corn starch is the base for the production of biofuel corn ethanol.

Health Effects

Corn starch, although a carbohydrate, has little to no nutritional value. The health benefits of this ingredient are debated. On one side, corn starch is a functional food ingredient, providing thickening and stabilizing properties. Without it, many sauces and puddings that we enjoy would lack texture and the desired consistency. In addition because it is a polysaccharide, it does not cause a spike in blood sugar levels upon consumption. On the other side, however, corn starch is typically added to not-so-healthy foods and due to its highly refined state, offers no real nutritional value.

In addition, corn starch most probably originates from genetically modified corn or GMO corn. Currently, 86% of the US corn crop is genetically modified. Specifically, corn has been genetically altered to resist certain herbicides. Other modifications include insect resistance and vitamin-enriched varieties. Many criticize that these genetic modifications were not tested thoroughly. Others demand that GMO corn ingredients should be labeled so that consumers can make an informed choice about consuming such products. Recent studies are not showing good support of GMO products. One study revealed that GMO corn caused organ damage when fed to rats. If GMO corn is an issue for your beliefs, there are non-GMO corn products available at health foods markets.

Origins

Corn starch is a product of the wet milling processing of corn. The process is well defined and efficiently uses all parts of the corn kernel. First, shelled corn is cleaned and placed in large steep tanks. The corn is soaked for 30-50 hours at 130 °F in a dilute solution of sulfur dioxide. This steeping process softens the corn kernel so the germ can be removed. The next step involves the removal of the bran fraction of the kernel leaving the endosperm.

The endosperm consists of mostly starch and some gluten. A centrifugational step is used to separate these two components. The gluten fraction is dried and is referred to as corn gluten meal. Corn starch makes up the remaining fraction and this starch milk is refined and purified by additional centrifugation steps. The dewatered starch obtained from this step is dried and passed through a fine sieve. The dried starch product can be modified for the particular end use by the addition of acids and other additives prior to the dewatering step.