Biotechnology and Molecular Biology Review Vol. 5(5), pp. 71 - 78 December 2010 Available online at http://www.academicjournals.org/BMBR ISSN 1538-2273 ©2010 Academic Journals Review High fructose corn syrup: Production, uses and public health concerns Kay Parker, Michelle Salas and Veronica C. Nwosu* Department of Biology, College of Science and Technology, North Carolina Central University, Durham, NC 27707, USA. Accepted 21 September, 2010 High fructose corn syrup (HFCS) is a liquid alternative sweetener to sucrose that is made from corn, the “king of crops” using chemicals (caustic soda, hydrochloric acid) and enzymes (-amylase and glucoamylase) to hydrolyze corn starch to corn syrup containing mostly glucose and a third enzyme (glucose isomerase) to isomerize glucose in corn syrup to fructose to yield HFCS products classified according to their fructose content: HFCS-90, HFCS-42, and HFCS-55. HFCS-90 is the major product of these chemical reactions and is blended with glucose syrup to obtain HFCS-42 and HFCS-55. HFCS has become a major sweetener and additive used extensively in a wide variety of processed foods and beverages ranging from soft and fruit drinks to yogurts and breads. HFCS has many advantages compared to sucrose that make it attractive to food manufacturers. These include its sweetness, solubility, acidity and its relative cheapness in the United States (US). The use of HFCS in the food and beverage industry has increased over the years in the US. The increase in its consumption in the US has coincided with the increase in incidence of obesity, diabetes, and other cardiovascular diseases and metabolic syndromes. This study examines literature on the production and properties of HFCS and the possible health concerns of HFCS consequent to its consumption in a wide variety of foods and beverages in the typical US diet. Key words: High fructose corn syrup, sweeteners, soft and juice drinks, baked goods, obesity, diabetes, metabolic syndrome, mercury; honey bees, colony collapse disorder. INTRODUCTION The bulk of the United States (US) diet comes from four containing amylose and amylopectin to corn syrup crops: corn, wheat, soybean, and rice. Of the four crops, containing mostly glucose followed by the isomerization corn is arguably the most dominant and most profitable to of the glucose in corn syrup to fructose to yield HFCS farm with its cultivation being highly subsidized by the US (Figure 1). Three categories of HFCS are in common government elevating corn to the “king of crops”. Corn use: HFCS-90 (90% fructose and 10% glucose) which is has been subjected to various genetic modifications that used in specialty applications but more importantly is have resulted in a crop that is resistant to pesticides, a blended with glucose syrup to yield HFCS-42 (42% feature that has increased the productivity of corn for fructose and 58% glucose) and HFCS-55 (55% fructose farmers. Corn is not only food for humans, but is also and 45% glucose). HFCS is called isoglucose in England feed for farm animals as diverse as cattle, pigs, and and glucose-fructose in Canada, and was first introduced poultry that are the major sources of meats for the US to the food and beverage industry in the late 1960s diet. Corn is the primary source of high fructose corn (HFCS-42 in 1967) and 1970s (HFCS-55 in 1977) to syrup (HFCS) in the US. Marshall and Kooi (1957) improve stability and functionality of various foods and developed the process for making HFCS. HFCS is made beverages. Carbohydrate sweeteners are craved for their by the chemical and enzymatic hydrolysis of corn starch sweetness because they enhance the taste and enjoy- ment of various foods. They are mostly monosaccharides such as glucose, fructose, and galactose; and disaccha- rides such as sucrose, lactose, and maltose. They come *Corresponding author. E-mail: [email protected]. Tel: in various forms such as cane and beet sugar, cane juice, (919)530-6170. Fax: (919) 530-7773. molasses, honey, fruit juice concentrates, corn syrups, 72 Biotechnol. Mol. Biol. Rev. and HFCS. Non carbohydrate sweeteners that have been Apergillus, breaks dextrins and oligosaccharides to the in use include saccharin (discovered in 1879); cyclamate simple sugar glucose. The product of these two enzymes (discovered in 1937); aspartame (discovered in 1965); is corn syrup also called glucose syrup. The third and acesulfame (discovered in 1967) and sucralose relatively expensive enzyme used in the process is (discovered in 1976). Sweeteners are measured on a glucose isomerase (also called D-glucose ketoisomerase sweetness index using sucrose as the baseline sugar or D-xylose ketolisomerase), that converts glucose to with a sweetness index of 1.0. The impetus for the search fructose. for alternative and non-caloric sweeteners to sucrose has While -amylase and glucoamylase are added directly historically been for better health for diabetics and also to the processing slurry, pricey glucose isomerase is for weight control. Cost is another major factor behind immobilized by package into columns where the glucose this search. The development of the relatively inexpen- syrup is passed over in a liquid chromatography step that sive HFCS has made it possible for it to become a viable isomerizes glucose to a mixture of 90% fructose and 10% alternative to sucrose and other natural sugars in a very glucose (HFCS-90). Whereas inexpensive -amylase and short time. HFCS represents approximately 40% of all glucoamylase are used only once, glucose isomerase is added caloric sweeteners in the US diet (Putnam and reused until it loses most of its enzymatic activity. The - Allshouse, 1999). Sucrose contains fructose and glucose amylase and glucoamylase used in HFCS processing in equal amounts linked by glucosidic bond. This bond have been genetically modified to improve their heat has to be broken to release both monosaccharides for stability for the production of HFCS. In the US, four metabolism. HFCS-55 contains more fructose than companies control 85% of the $2.6 billion HFCS glucose and this fructose is more immediately available business—Archer Daniels Midland, Cargill, Staley Manu- because it is not bound up in sucrose. There are facturing Co, and CPC International. differences in the metabolism of glucose and fructose With clarification and removal of impurities, HFCS-90 is with that of glucose being better understood than that of blended with glucose syrup to produce HFCS-55 (55% fructose. The use of HFCS in the food and beverage fructose) and HFCS-42 (42% fructose). Both HFCS-55 industry has increased over the years in the US. This and HFCS-42 have several functional advantages in study examines literature on the production and proper- common, but each has unique properties that make them ties of HFCS and the possible health concerns of HFCS attractive to specific food manufacturers. Because of its consequent to its consumption in a wide variety of foods higher fructose content, HFCS-55 is sweeter than and beverages in the typical US diet. The health imply- sucrose and is thus used extensively as sweetener in cation of HFCS consumption is subject to intense debate. soft, juice, and carbonated drinks. HFCS-42 has a mild The increase in its consumption in the US has coincided sweetness and does not mask the natural flavors of food. with the increase in incidence of obesity, diabetes, and Thus it is used extensively in canned fruits, sauces, other cardiovascular diseases and metabolic syndromes. soups, condiments, baked goods, and many other Thus published literature was surveyed to collate data on processed foods. It is also used heavily by the dairy the impact of HCFS on human health. Of concern is the industry in yogurt, eggnog, flavored milks, ice cream, and possible contamination of HFCS with mercury during other frozen desserts. The use of HFCS has increased processing. Also of concern is the possible toxicity of since its introduction as a sweetener (Figure 2). Although, HFCS and its by-products to honey bees. its use peaked in 1999, it rivals sucrose as the major sweetener in processed foods. The US is the major user of HFCS in the world, but HFCS is manufactured and PRODUCTION AND USES OF HFCS used in many countries around the world (Vuilleumier, 1993). HFCS has functional advantages relative to The schematic of HFCS production is shown in Figure 1. sucrose. HFCS is produced from corn. The corn grain undergoes These include HFCS’s relative cheapness (at 32 several unit processes starting with steeping to soften the cents/lb versus 52 cents/lb for sucrose); greater hard corn kernel followed by wet milling and physical sweetness with HFCS being sweeter than sucrose (Table separation into corn starch (from the endosperm); corn 1), better solubility than sucrose (Table 2) and ability to hull (bran) and protein and oil (from the germ). Corn remain in solution and not crystallize as can sucrose starch composed of glucose molecules of infinite length, under certain conditions. Moreover, HFCS is liquid and consists of amylose and amylopectin and requires heat, thus is easier to transport and use in soft drink caustic soda and/or hydrochloric acid plus the activity of formulations (Hanover and White, 1993). It is also acidic three different enzymes to break it down into the simple and thus has preservative ability that reduces the use of sugars glucose and fructose present in HFCS. An other preservatives. HFCS has little to no nutritional value industrial enzyme, -amylase produced from Bacillus other than calories from sugar (Table 3). Analysis of food spp., hydrolyzes corn starch to short chain dextrins and consumption patterns using USDA (2008) food consump- oligosaccharides. A second enzyme, glucoamylase (also tion tables for the US from 1967 to 2000 (Bray et al., called amyloglucosidase), produced from fungi such as 2004) showed that HFCS consumption increased Parker et al 73 Corn Starch Amylose and Amylopectin Heat Chemicals - Amylase Dextrins and Maltodextrins Heat Chemicals Glucoamylase AKA Amylo- glucosidase Glucose syrup AKA: Corn Syrup Glucose Isomerase: Column immobilized HFCS-90 Blending with Glucose Syrup Figure 1.