Corn is an American success story. Nearly 8 billion bushels are grown in the United States every year. Now 8 billion is an impressive number but, since I have no idea what a bushel is, I am not immediately impressed. My helpful dictionary says a bushel is really 4 pecks. No help there. A little more investigation and a bushel proves to be a box a little more than a foot on a side. So that’s about 10 billion cubic feet or roughly 864 ears of corn for every person in the US. I don’t know about you, but I don’t eat that much corn. What’s done with it? Some of it is used to feed livestock. Some of it is turned into whiskey. And, over a billion bushels are used by corn refiners to produce corn starch and corn syrup.
A grain of corn is nearly 70% starch in the form of long strings of molecules that can be straight like hay or branching like tree limbs. These strings are organized in spherical patterns forming starch granules. When heated in solution, the starch granules absorb water and eventually gelatinize into a paste. Starch gel temperature and character can be selected by choosing from among hundreds of strains of corn and further controlled by manufacturing steps. Food starches are produced that thicken soups, sauces, pie fillings and even yogurts. They help suspend fats and proteins in gravies, salad dressings and puddings. Industrial applications include a wide range of glues, pastes and coatings. It is said the Egyptians used a starch coating to improve their papyrus. Even today, paper and textiles are sized with starch to improve strength and appearance. Cornstarch powder is misted between sheets of paper during printing to prevent ink smear. And, that very same cornstarch is patted on a million baby bottoms every day.
Unfortunately, the very first step in corn refining is a 2-day soak in hot water laced with sulfur dioxide. This is called steeping. Then the kernels are ground into a slurry, centrifuged and screened to separate the oil, protein and starch. The starch is washed and dried, looks pure and white, but carries traces of the original sulfur dioxide. The United Nations Codex Alimentarius Commission writes standards for the international food industry. Refined corn products are classified as food additives and are covered in a book called the Food Chemicals Codex. When I pulled a Codex off the shelf of a local university library, it looked and smelled brand new. I must have been its only visitor in many years. Codex rules state that a corn starch may contain up to 50 ppm (parts per million) of sulfur dioxide. This is a maximum, so it is reasonable that the effective SOx concentration listed in our Oxides of Sulfur Ingredient Table is about half that.
Starch strings are built of sugar-like molecules. If the strings are broken into smaller pieces by acids or enzymes, the starches become slightly sweet. Maltodextrin and polydextrose fall into this category of slightly sweet starches. The shorter the strings, the sweeter the starch until you finally get pure sugars in the form of glucose syrup, commonly known as corn syrup. If the corn syrup is crystallized, you get dextrose. If it is dried, you get corn syrup solids. All of these forms of corn syrup have effective sulfur oxide concentrations about half that of starch. The sulfur oxide is lowered as the processing continues. Corn syrup and dextrose are not quite as sweet as the sucrose in cane or beet sugar. This limited the appeal of refined corn until 1970 when high fructose corn syrup was born. Since fructose is slightly sweeter than sucrose, the cane and the beet had met their match. High fructose corn syrup is economically manufactured at 42%, 55% and 90% fructose and further processing can produce pure crystalline fructose. High fructose corn syrup and fructose are so highly refined that much of the sulfur dioxide is left behind and the effective concentrations are usually low enough to be ignored. As a matter of fact, they are almost as low in sulfur as cane and beet sugar.
Corn starches and syrups are the most common sulfured ingredients in modern foods. They are to be found in nearly every packaged product in your supermarket. This may be a slight exaggeration, but it sure seems that way when I am shopping for clean foods. Why should refined corn products be so popular? They are economical, easy to handle and available in a wide range of designer styles. Also, America’s corn crop is enormous and refined corn consumes only a small part. This makes refined corn a stable, reliable product with plenty of room to grow. And, the uses of refined corn are seemingly endless. In addition to the traditional uses of cornstarch, the slightly sweet starches like maltodextrin are used as bulking and texturing agents. This is extremely important for the low sugar and fat free products that are currently so popular. When you take out sugar and fat, you have to put something back in or things just don’t taste and feel right. What better than a slightly sweet and creamy starch that contributes zero sugar and zero fat to the food label?
For more than a year, I ate Smucker’s Light Strawberry Preserves to avoid the high fructose corn syrup common in most other jams. Well, you just can’t cheat the Brimstone Demons. Smucker’s Light Preserves contain maltodextrin and polydextrose to make up for the missing corn syrup. Unfortunately, the sulfur in these starches is much worse than the high fructose corn syrup I was trying to avoid. The 100% fruit products are no help. They use grape juice concentrate instead of sugar or corn syrup. And, grapes have their own special sulfite problem. So do the sweeteners used by many diabetics, the alcohol sugars like sorbitol, malitol and xylitol. Unfortunately, sorbitol and its friends are usually made from good old corn starch just like corn syrup. And they have SOx ratings about the same as corn syrup. These days, I mostly use honey.
The big break for refined corn came in 1984, when Coke and Pepsi decided to switch from sugar to high fructose corn syrup. Cola bottle labels declare a mixture of "high fructose corn syrup and/or sugar". But guess what’s in the bottle? That 1984 decision to switch to corn syrup contributed to riots in the Philippines where cane sugar production collapsed. And, it put corn refining on a growth curve that can only be matched by Microsoft and Google. Take a look at the graph of corn sweetener production from 1950 to 1995. This graph is a reflection of a fundamental shift in American food habits. In 1950, the corn syrup share of the US nutritive sweetener market was a paltry 10%. By 1995, this share was over 50%, bigger than cane and beet sugar combined. And it keeps on growing…like a giant blob of sweet, pulsating syrup.