Sugar and other sweeteners used in food can be derived from a variety of plants, including the sugar beet, sugar cane, maple tree, stevia plant, and some species of palms. But one of the most commonly used plants for producing sugar is corn. It is found in food items as corn syrup, high fructose corn syrup, or, as the corn refiners prefer to market it as “corn sugar.”
What Foods Use Corn Syrup
Corn syrup is used in many of the food products on the market today, including canned fruits and vegetables, snack foods, processed meats, crackers, ice cream, and soda and other beverages. In addition, corn syrup is used to flavor non-food products, such as the adhesive on an envelope flap or stamps. Corn syrup is far less expensive to process than other sweetener options, and as a result, it is an ingredient that is nearly impossible to avoid consuming.
The use of corn as a food dates back to as early as 4000 B.C., when it was grown in the region known today as Oaxaca, Mexico. The hardy plant thrived in almost any weather and soil conditions, and was later exported to Spain and then to other parts of Europe. As the popularity of corn as food grew, so did the technologysurrounding the processing of the grain. Water-powered mills that had been used to grind wheat were adapted to grind corn, and by the 1700s, a device had been made that would easily remove corn from the cob.
Invention of Corn Syrup
Though corn itself is viewed as a member of the grain family, the sugars that are made from corn are actually derivatives of the starch from the corn. The process of converting starches into sweeteners began in Japan in the 800s, using arrowroot. In 1811, a Russian chemist named G.S.C. Kirchoff rediscovered the ability to convert starch to sugar when he heated potato starch in a diluted amount of sulfuric acid to create several starch-derived sweeteners, including dextrose.
In the United States, the method of using acid to create sweeteners was the primary way corn syrup was created until 1967, when an enzyme process was used to create high fructose corn syrup. At first, this new method took several days to complete, but in 1972, the method had been refined so that the process was reduced to only several hours.
How Corn Syrup is Made
Like any food additive that is derived from a natural ingredient, the process by which corn syrup is made involves many different steps. The steps below were explained and illustrated in the 1999 publication of How Products Are Made: An Illustrated Guide to Product Manufacturing.
Transporting the Corn: Dried corn kernels are transported to the refinery where the corn is weighed and stored prior to processing. The corn may come from just one farm, or be a mixture of corn kernels from many different farms.
Sorting the Corn for Corn Syrup Processing: The kernels are then sent down a vibrating conveyor belt, where debris such as sticks and cobs, is removed. Electromagnets remove any nails, screws, or other bits of metal that may be mixed in with the kernels. A controlled blast of air cleans off any dust or sediment that may have settled on the kernels.
Softening the Corn Kernels: The sorted kernels are then moved into large, stainless steel holding tanks called “steep tanks.” These tanks hold about 168,000 pounds of corn kernels. Warm water, with a small amount of sulfur dioxide is then circulated throughout the tanks. This continues for 20 – 40 hours, until the kernels are soft. This softening of the corn kernels allows the starch to be more easily withdrawn from the corn.
The First Milling Process: During this coarse grinding process, the inner part of the corn kernel, the germ, is separated from the outer part of the kernel. The cleaned germs are then heated and the corn oil is extracted.
Separating the Starch, Protein, and Fiber: A machine then separates the starch, protein, and fiber from one another. The fiber portion is then dried and sent off to become animal feed or corn bran fiber for use in cereals. The protein is called gluten, and is dried, and then sold as animal feed. The starch is diluted with water, then washed and filtered, to remove any remaining protein. Some of the corn starch is dried and used for food, building products, and chemicals. The rest of it, usually the majority, is converted into corn sweeteners.
Corn Starch to Corn Syrup: Using a process called acid hydrolysis, the corn is then converted into corn syrup. The syrup is then filtered and refined to remove as much water as possible. Some of the corn syrup is dried and made into a corn syrup powder.
Corn syrup to High Fructose Corn Syrup with Enzyme Conversion: Ordinary corn syrup contains dextrose sugar, which is only about three-quarters as sweet as the sucrose found in cane or beet sugar. In many situations, this is an advantage, because it does not overtake the other flavors in food. However, when a higher sweetness is desired, the corn syrup undergoes another process called enzyme conversion. In this process, the dextrose is converted to an even sweeter product called fructose.
How to Eat Less High Fructose Corn Syrup in the Diet
High fructose corn syrup, or HFCS, has been an ingredient involved in controversy and a difference of opinion by many food industry spokespeople and the medical community. In fact, the attention of the negative side effects of consuming high fructose corn syrup has been so strong, that the corn refining industry started a campaign in 2010 to rebrand corn syrup as “corn sugar.”
Katherine Zeratsky, R.D., L.D., of the Mayo Clinic recommends that those concerned with high fructose corn syrup in the diet follow these guidelines:
- Consume less soda
- Choose fruits and vegetables that are canned in their own juices instead of syrups
- Prepare foods from fresh ingredients, instead of processed items
- Avoid foods that have added sugar
- If fruit juice is a must, look for juices that have no added sugar, or are labeled 100% juice