High-fructose corn syrup (HFCS)—also called glucose/fructose in Canada, glucose–fructose syrup (GFS) in the EU, and high-fructose maize syrup in other countries —comprises any of a group of corn syrups that has undergone enzymatic processing to convert some of its glucose into fructose to produce a desired sweetness.
In the United States, consumer foods and products typically use high-fructose corn syrup as a sweetener. It has become very common in processed foods and beverages in the U.S., including breads, cereals, breakfast bars, lunch meats, yogurts, soups, and condiments.
HFCS consists of 24% water, and the rest sugars. The most widely used varieties of high-fructose corn syrup are: HFCS 55 (mostly used in soft drinks), approximately 55% fructose and 42% glucose; and HFCS 42 (used in beverages, processed foods, cereals and baked goods), approximately 42% fructose and 53% glucose. HFCS-90, approximately 90% fructose and 10% glucose, is used in small quantities for specialty applications, but primarily is used to blend with HFCS 42 to make HFCS 55.
1. Use as a replacement for sugar
In the United States, HFCS is among the sweeteners that have primarily replaced sucrose (table sugar) in the food industry. Factors for this include governmental production quotas of domestic sugar, subsidies of U.S. corn, and an import tariff on foreign sugar, all of which combine to raise the price of sucrose to levels above those of the rest of the world, making HFCS cheaper for many sweetener applications. The relative sweetness of HFCS 55 is comparable to table sugar (sucrose), a disaccharide of fructose and glucose, (HFCS 90 is sweeter than sucrose and HFCS 42 is less sweet than sucrose) while, being a liquid, HFCS is easier to blend and transport.
2. Comparison to other sweeteners
2.1 Cane and beet sugar
Cane sugar and beet sugar are both relatively pure sucrose. While glucose and fructose, which are the two components of HFCS, aremonosaccharides, sucrose is a disaccharide composed of glucose and fructose linked together with a relatively weak glycosidic bond. The fact that sucrose, glucose and fructose are unique, distinct molecules complicates the comparison between cane sugar, beet sugar and HFCS. A molecule of sucrose (with a chemical formula of C12H22O11) can be broken down into a molecule of glucose (C6H12O6) plus a molecule of fructose (also C6H12O6 — an isomer of glucose) in a weakly acidic environment by a process called inversion. Sucrose is broken down during digestion into a mixture of 50% fructose and 50% glucose through hydrolysis by the enzyme sucrase. People with sucrase deficiency cannot digest (break down) sucrose and thus exhibit sucrose intolerance.
Honey is a mixture of different types of sugars, water, and small amounts of other compounds. Honey typically has a fructose/glucose ratio similar to HFCS 55, as well as containing some sucrose and other sugars. Like HFCS, honey contains water and has approximately 3 kcal per gram. Because of its similar sugar profile and lower price, HFCS has been used illegally to “stretch” honey. As a result, checks for adulteration of honey no longer test for higher-than-normal levels of sucrose, which HFCS does not contain, but instead test for small quantities of proteins that can be used to differentiate between HFCS and honey.
HFCS was first introduced by Richard O. Marshall and Earl R. Kooi in 1957. They were, however, unsuccessful in making it viable for mass production. The industrial production process and creation was made by Dr. Yoshiyuki Takasaki at the Agency of Industrial Science and Technology of Ministry of International Trade and Industry of Japan in 1965–1970. HFCS was rapidly introduced to many processed foods and soft drinks in the U.S. from about 1975 to 1985.
High-fructose corn syrup is produced by milling corn to produce corn starch, then processing that starch to yield corn syrup, which is almost entirely glucose, and then adding enzymes that change some of the glucose into fructose. The resulting syrup (after enzyme conversion) contains approximately 42% fructose and is HFCS 42. Some of the 42% fructose is then purified to 90% fructose, HFCS 90. To make HFCS 55, the HFCS 90 is mixed with HFCS 42 in the appropriate ratios to form the desired HFCS 55. The enzyme process that changes the 100% glucose corn syrup into HFCS 42 is as follows:
- alpha-amylase – produces shorter chains of sugars called oligosaccharides from raw cornstarch.
- Glucoamylase – breaks the oligosaccharides down even further to yield the simple sugar glucose.
- Xylose isomerase (aka glucose isomerase) – converts glucose to a mixture of about 42% fructose and 50–52% glucose with some other sugars mixed in.
Although both types of amylase are naturally produced by many animals (including humans), the most common method of commercial production is microbial fermentation. Xylose isomerase is not native to animals; and in standard glycolysis the glucose molecules are isomerized only after phosphorylation by glucose-6-phosphate isomerase yielding fructose 6-phosphate. Fructose molecules are phosphorylated by fructokinase and enter the glycolytic pathway at this point.
While inexpensive alpha-amylase and glucoamylase are added directly to the slurry and used only once, the more costly xylose-isomerase is packed into columns and the sugar mixture is then passed over it, allowing it to be used repeatedly until it loses its activity. This 42–43% fructose glucose mixture is then subjected to a liquid chromatography step, where the fructose is enriched to about 90%. The 90% fructose is then back-blended with 42% fructose to achieve a 55% fructose final product. Most manufacturers use carbon adsorption for impurity removal. Numerous filtration, ion-exchange and evaporation steps are also part of the overall process.
The units of measurement for sucrose is degrees Brix (symbol °Bx). Brix is a measurement of the mass ratio of dissolved sucrose to water in a liquid. A 25 °Bx solution has 25 grams of sucrose per 100 grams of solution (25% w/w). Or, to put it another way, there are 25 grams of sucrose and 75 grams of water in the 100 grams of solution. The Brix measurement was introduced by Antoine Brix.
A more universal measurement of sugars, including HFCS, is called dry solids. Dry solids is defined as the mass ratio of dry sugars to the total weight of the sugar solution. Since Brix is based on the refractive index of light against a sucrose molecule it is not accurate when measuring other sugars such as glucose, maltose, and fructose.
When an infrared Brix sensor is used, it measures the vibrational frequency of the sucrose molecules, giving a Brix degrees measurement. This will not be the same measurement as Brix degrees using a density or refractive index measurement, because it will specifically measure dissolved sugar concentration instead of all dissolved solids. When a refractometer is used, it is correct to report the result as “refractometric dried substance” (RDS). One might speak of a liquid as being 20 °Bx RDS. This is a measure of percent by weight of total dried solids and, although not technically the same as Brix degrees determined through an infrared method, renders an accurate measurement of sucrose content, since the majority of dried solids are in fact sucrose.
Recently, an isotopic method for quantifying sweeteners derived from corn and sugar cane was developed which permits measurement of corn syrup- and cane sugar-derived sweeteners in humans, thus allowing dietary assessment of the intake of these substances relative to total intake.
4. Sweetener consumption patterns
Prior to the development of the worldwide sugar industry, dietary fructose was limited to only a few items. Milk, meats and most vegetables, the staples of many early diets, have no fructose and only 5–10% fructose by weight is found in fruits such as grapes, apples and blueberries. Molasses and common dried fruits have a content of less than 10% fructose sugar. From 1970 to 2000 there has been a 25% increase in “added sugars”.
4.2 United States
US sweetener consumption, 1966–2009, in dry pounds. It is apparent from this graph that overall sweetener consumption, and in particular glucose-fructose mixtures, has increased since the introduction of HFCS. Thus, the amount of fructose consumed in the United States has increased since the early 1980s. This would be true whether the added sweetener was HFCS, table sugar, or any other glucose-fructose mixture.
A system of sugar tariffs and sugar quotas imposed in 1977 in the United States significantly increased the cost of imported sugar and U.S. producers sought cheaper sources. High-fructose corn syrup, derived from corn, is more economical because the domestic U.S. prices of sugar are twice the global price and the price of corn is kept low through government subsidies paid to growers.
HFCS became an attractive substitute, and is preferred over cane sugar among the vast majority of American food and beverage manufacturers. Soft drink makers such as Coca-Cola and Pepsi use sugar in other nations, but switched to HFCS in the U.S. in 1984. Large corporations, such as Archer Daniels Midland, lobby for the continuation of government corn subsidies.
Other countries, including Mexico, typically use sugar in soft drinks. Some Americans seek out Mexican Coca-Cola in ethnic groceries because they prefer the taste compared to Coke made with HFCS. Kosher for Passover Coca-Cola sold in the U.S. around theJewish holiday also uses sucrose rather than HFCS and is also highly sought after by people who prefer the original taste.
The average American consumed approximately 37.8 lb (17.1 kg) of HFCS in 2008, versus 46.7 lb (21.2 kg) of sucrose.
4.3 European Union
In the European Union (EU), HFCS, known as isoglucose or glucose-fructose syrup, is subject to a production quota. In 2005, this quota was set at 303,000 tons; in comparison, the EU produced an average of 18.6 million tons of sugar annually between 1999 and 2001. Wide-scale replacement of sugar with HFCS has not occurred in the EU.
In Japan, HFCS consumption accounts for one quarter of total sweetener consumption.
Health concerns have been raised about high fructose corn syrup, which allege contribution to obesity, cardiovascular disease, diabetes, and non-alcoholic fatty liver disease. Critics of the extensive use of HFCS in food sweetening argue that the highly processed substance is more harmful to humans than regular sugar, contributing to weight gain by affecting normal appetite functions. The use of food grade hydrochloric acid in the processing of corn syrup has given rise to the unconfirmed speculations that HFCS itself is a source of inorganic mercury a known neurotoxin. The food industry does no longer use conventional chemical hydrolysis for the manufacture of HFCSs but instead a multi-step bioprocess with bacterial enzymes is applied. TheCorn Refiners Association disputes these claims and maintains that HFCS is comparable to table sugar. Studies by the American Medical Association suggest “it appears unlikely that HFCS contributes more to obesity or other conditions than sucrose”, but welcome further independent research on the subject. Further reviews in the clinical literature have disputed the links between HFCS and obesity, type 2 diabetes, and metabolic syndrome, and concluded that HFCS is no different from any other sugar in relationship to these diseases. HFCS has been classifiedgenerally recognized as safe (GRAS) by the U.S. Food and Drug Administration since 1976. Yet further study showed that with dietary zinc (Zn) loss and copper (Cu) gain from the consumption of high fructose corn syrup (HFCS), metabolic processes required to eliminate heavy metals are impaired in autistic children.
It is important to note that many sources agree that research conducted in the lab setting is often different from consumption of HFCS in everyday life. These sources point out that laboratory research often tests only fructose rather than one of the blends of fructose and glucose that makes up HFCS. When considering how results of any research is applicable to you it is important to know how the lab setting and everyday settings relate and to be cautious of reports that make great claims. That being said more research still needs to be done on the topic of HFCS and the human body.
While the growth of fructose consumption in many developed nations coincides with the increase of prevalence of obesity, medical research to date is inconclusive, with contradictory conclusions presented by various research teams. The consensus supported by many health professionals and nutrition experts points at an overall excessive use of carbohydrates, particularly sugar-sweetened beverages, that lead to weight gain, due to a decreased effect on satiety.
In the United States, high-fructose corn syrup has become a sucrose replacement for honey bees. In 2009, a study by Leblanc et al. found that at temperatures above 45 °C (113 °F) HFCS rapidly forms hydroxymethylfurfural, which is toxic to the honey bees being fed HFCS. In 2012, a study by Chensheng Lu et al. found that beehives fed HFCS laced with imidacloprid, a pesticide commonly used on corn crops, died out at a higher rate than beehives fed imidacloprid-free HFCS.
7. Public relations
There are various public relations issues with high-fructose corn syrup, including its labeling as “natural”, its advertising, companies that have moved back to sugar, and a proposed name change to ‘corn sugar’. In 2010 the Corn Refiners Association applied to allow HFCS to be renamed ‘corn sugar’, but was rejected by the US Food and Drug Administration in 2012.PMID
This article uses material from the Wikipedia article High-Fructose Corn Syrup, which is released under the Creative Commons Attribution-Share-Alike License 3.0.