Corn CONTENTS Member Companies and Pland Locations ...... 2 Foreword ...... 3 Introduction ...... 4 The Corn Wet Milling Industry ...... 5 General Manufacturing System ...... 6 CONTENTS Corn Oil Manufacturing Process ...... 9 Packaging, Transport and Storage ...... 13 Physical and Chemical Properties ...... 14 Nutritional Properties ...... 16 Production and Commercial Uses ...... 19 Analytical Examination of Corn Oil ...... 22

TABLES 1. Proximate Analysis of Yell Grain ...... 6 2. Comparative Composition of Crude & Refined Corn Oil ...... 12 3. Approximate Composition of Refined Corn Oil: Nutrient Values ...... 14 4. Food Chemicals Codex Specifications for Refined Corn Oil ... 15 5. Typical Chemical and Physical Data for Refined Corn Oil ...... 15 6. Production, 2004 ...... 19

FIGURES 1. A Kernel of Corn ...... 6 2. The Corn Wet Milling Process ...... 7 3. Corn Oil Refining...... 11 4. Nutritional Labeling of Corn Oil ...... 16

Corn Refiners Association 1701 Pennsylvania Avenue, N.W. Washington, D.C. 20006-5805 202-331-1634 Fax: 202-331-2054 www.corn.org 1 5th Edition Copyright 2006 MEMBER COMPANIES PLANT LOCATIONS Archer Daniels Midland Company Plants: P.O. Box 1470 Cedar Rapids, Iowa 52404 Decatur, Illinois 62525 Clinton, Iowa 52732 Columbus, Nebraska 68601 Decatur, Illinois 62525 Marshall, Minnesota 56258-2744

Cargill, Incorporated Plants: P.O. Box 5662/MS62 Blair, Nebraska 68008-2649 Minneapolis, Minnesota 55440-5662 Cedar Rapids, Iowa 52406-2638 Dayton, Ohio 45413-8001 Eddyville, Iowa 52553-5000 Hammond, Indiana 46320-1094 Memphis, Tennessee 38113-0368 Wahpeton, North Dakota 58075

Corn Products International, Inc. Plants: 5 Westbrook Corporate Center Bedford Park, Illinois 60501-1933 Westchester, Illinois 60154 Stockton, California 95206-0129 Winton-Salem, North Carolina 27107

National Starch and Chemical Company Plants: 10 Finderne Avenue Indianapolis, Indiana 46221 Bridgewater, New Jersey 08807-0500 North Kansas City, Missouri 64116

Penford Products Co. Plant: (A company of Penford Corporation) Cedar Rapids, Iowa 52404-2175 P.O. Box 428 Cedar Rapids, Iowa 52406-0428

Roquette America, Inc. Plant: 1417 Exchange Street Keokuk, Iowa 52632-6647 Keokuk, Iowa 52632-6647

Tate & Lyle Ingredients Americas, Inc. Plants: (A subsidiary of Tate & Lyle, PLC ) Decatur, Illinois 62521 P.O. Box 151 Lafayette, Indiana 47902 Decatur, Illinois 62521 Lafayette, Indiana 47905 Loudon, Tennessee 37774

2 Golden corn oil sitting on the pantry shelf often serves as the most visible sign of the corn refining industry to most Ameri- cans. Although corn oil represents a relatively modest amount of all food ingredients produced by corn refiners, its household use reminds consumers of the vast array of food and industrial products derived from our most abundant crop. FOREWORD Long the preferred food oil for discerning consumers, corn oil was limited in supply until recent years. The growth of corn refining over the last twenty years, has led to greater supplies of corn oil being available for domestic consumption while also contributing to the U.S. balance of trade through exports.

The modern corn refining process creates various food and industrial starches, sweeteners, alcohols, oil, feed ingredients and bioproducts. Each offers an excellent example of the way we can add value to raw agricultural commodities. By doing so, we expand markets for U.S. farmers, increase employment through processing and provide a wide array of useful products to American industry and consumers.

We hope you will find this booklet about corn oil useful. Please contact the Corn Refiners Association, if you would like more information on corn refining and its products.

Audrae Erickson President Corn Refiners Association

Readers are advised that the information and suggestions contained herein are general in nature and that specific technical questions should be referred to the Association or its member companies. Questions as to the price and/ or availability of products described should be directed to individual Asso- ciation members.

3 As the corn refining industry clearly from other edible veg- expanded its product portfo- etable . About 95 percent lio and processed more corn, of domestically produced the quantity of corn oil avail- corn oil is from the corn wet able increased dramatically. milling industry, and all but a INTRODUCTION Corn oil has become an im- small fraction is used in one portant item in the mix of form or another as food. products manufactured from America’s most important This booklet presents a brief crop, and is no longer thought history and current descrip- of as simply another co-prod- tion of the corn wet milling uct of starch manufacture. industry and products; a de- scription of the corn oil Annual production of crude manufacturing process; com- corn oil currently exceeds 2.4 position, physical and chemi- billion pounds. Nearly all of cal properties of corn oil; commercial uses and end it is refined into high-quality products utilizing corn oil; oil for the food industry and nutritional considerations; and direct use by consumers. In a listing of methods for iden- the 1950s, medical researchers tification and analysis of corn found that corn oil was effec- oil. It is the fourth in a series tive in reducing serum choles- of booklets describing prod- terol in humans. This re- ucts from corn. Subjects of search gave rise to an other volumes are: corn increased demand for corn oil starch; nutritive sweeteners that continues today. from corn; and corn wet milled feed products. Corn refiners invested in re- search and development that The growth of corn oil in the has resulted in production of marketplace is based on its edible oils of consistently high functionality, economy, and quality. Concurrently, devel- acceptability in relation to opment of new and improved other or oils. Among products using corn oil, many these factors, functionality is of them conceived in re- foremost. For health reasons, sponse to health-related re- corn oil has replaced a signifi- search in foods and nutrition, cant amount of saturated has given this oil a market and is also a top choice for identity that is widely recog- trans fat reduction in numer- nized and differentiates it ous food products.

4 BACKGROUND hydrate — which became a The origins of the American commercial product within corn wet milling industry can a few years. In the 1950s, be traced back to 1842, when syrups in a range of con- Thomas Kingsford began the trolled levels of sweetness commercial manufacture of approaching that of pure THE CORN WET dextrose entered the mar- starch from corn. Previously, MILLING INDUSTRY starch was made from wheat ket. In 1967, enzymatic and potatoes, starting as a transformation of glucose cottage industry in the colo- to fructose was introduced, nial period. The first starch leading to production of factory had been established high fructose . in New England in 1802 to Since the late 1980s, sweet- provide potato starch for cot- eners derived from corn ton cloth mills. By 1860, a have supplied the majority substantial amount of corn- of the U.S. nutritive sweet- starch was being produced in ener market. A wide vari- many small plants scattered ety of starches and starch about the country. U.S. con- derivatives are now pro- sumption of cornstarch duced to fill the needs of reached about 210 million many different industries. pounds in the 1880s, but there Additionally, corn refiners was significant overproduc- are branching out to pro- tion and many of the small duce a wide variety of spe- plants closed. After 1900, cialty food and feed addi- there was a steady increase in tives through other consumption and most of the fermentation processes. small plants were replaced by Co-products from corn a small number of large refining make important plants. By this time, corn had contributions to livestock succeeded wheat and potatoes feeds. Production of high- as the principal source of quality corn oil increases in starch. Thereafter the indus- direct proportion to the try enjoyed continuing growth growing volume of corn while it began to diversify into going to starch, sweetener, the complex processing indus- ethanol and bioproduct try that corn refining is today. production, and the oil has found a unique and special Corn syrups became a well- place among edible oils. known article of commerce and household use in the lat- The current growth and ter part of the nineteenth development of corn refin- century. By 1921, research led ing, characterized by ad- to a pure sugar from corn vanced technology, the syrup — crystalline dextrose large number and diversity 5 of products and variety of protein (gluten) are intermixed industries served, demon- and require more drastic treat- strates that the , ment for separation. Table 1 like crude petroleum, has shows the chemical composition become an important source considered representative of of chemical feedstocks. American yellow hybrid dent GENERAL corn. MANUFACTURING SYSTEM COMPONENTS OF THE Starch CORN KERNEL Figure 1 is a cross sectional dia- gram of the corn kernel, show-

ing the general structure and lo- Endosperm Hull Starch Fiber and cation of the major components Germ of interest in the milling process. Gluten The outer layers (hull, or bran and tip-cap), which account for about Figure 1. 6 percent of the kernel’s weight, A Kernel of Corn. become a component of feed Figure 2 is a flow chart of the products. The germ (embryo), corn wet milling process, show- in which most of the oil resides, ing the paths of the corn kernel is about 11.5 percent. The re- through equipment, processes, mainder of the kernel is en- and intermediate products to dosperm. Floury endosperm the four main categories of (white portion of the drawing) is output products: starch, sweet- mostly soft starch, easily sepa- ener, animal feed and oil. Nutri- rated and recovered. The stippled tive sweeteners are further re- portion of Figure 1 is horny en- fined to produce fermentation dosperm, in which starch and products and other chemicals

Table 1. Characteristic Range Average Proximate Analysis of Moisture (% wet basis) 7 – 23 16.0 Yellow Dent (% dry basis) 61 – 78 71.7 Grain Protein (% dry basis) 6 – 12 9.5 Fat (% dry basis) 3.1 – 5.7 4.3 Ash (oxide) (% dry basis) 1.1 – 3.9 1.4 Pentosans (as xylose) (% dry basis) 5.8 – 6.6 6.2 Fiber (neutral detergent residue) (% dry basis) 8.3 – 11.9 9.5 Cellulose + Lignin 3.3 – 4.3 3.3 (acid detergent residue) (% dry basis) Sugars, Total (as glucose) (% dry basis) 1.0 – 3.0 2.6 Total Carotenoids (mg/kg) 12 – 36 26.0

Reprinted with permission form White, P.J., and Johnson, L.A., eds., 2003, Corn Chemistry and Technology, American Association of Cereal Chemists, St. Paul, MN.

6 such as amino acids, organic in a series of tanks, which are acids and polyols. operated in a continuous-batch process. The water circulates THE CORN WET MILLING counter currently through the tanks, so when it is finally with- PROCESS drawn from the newest batch, it Shelled corn enters the system has a relatively high concentra- through cleaning machines, tion of solubles. The steeping which remove foreign material. process facilitates separation of Cleaned corn then goes to a the components of the kernel steep tank holding up to and loosens the gluten bonds to 25,000 bushels, where it soaks release the starch. Discharged in circulating water, maintained steepwater, rich in protein at 35 at 125°F and slightly acidified to 45 percent of total solids, is with 0.1 to 0.2 percent of sul- concentrated in vacuum evapo- fur dioxide. Steeping the corn rators to a solids content of 35 for 24 to 48 hours softens the to 55 percent. Steepwater con- kernel, loosens the hull and centrate is utilized in feed prod- germ and swells the en- ucts or in industrial fermentation dosperm. Steeping takes place media. Figure 2 The Corn Wet Milling Process

Shelled Corn ○○○○○○○○○○

Corn Cleaners

○○○○○○ Hydroclone ○○○○○○○○○○○○○○○○○○○○○○○○○○○ Steep Tanks ○○○○○○○○Germ Grinding Mills Screens Centrifugal Separators Separators Starch Washing ○○○○○ ○○○○○○○○○○○○○○○○ ○○○○○○○○○○○○

Steepwater Germ Fiber Gluten

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ ○○○○○○○○○○○ Germ Washing

and Drying ○○○○

○○○○○ Refinery Clean, Dry Germ

Oil Expellers Corn Germ and Extractors ○○○○○○○○○○Meal Starch Nutritive Crude Oil Products Sweeteners ○○○○

○○○○○ Feed Oil Refining Products (See Fig. 3) Fermentation and Refined Other Chemicals Corn Oil

7 Softened corn from the steep PRODUCTS tanks is coarsely ground with End products of the wet mill- water in an attrition mill to ing process are purified starch, free the hull, the germ and a a collection of feed products, large portion of the floury and crude corn oil. Commer- endosperm starch and gluten. cial starch products are then The slurry of coarsely ground manufactured in great variety, corn is forced under pressure including unmodified corn- into hydroclones, which cen- starch, acid-modified and oxi- trifugally separate the lighter dized starches, dextrins, and corn germ, which is then car- starch derivatives. Detailed ried off to washing screens. information on starch process- Washed germ is conveyed to a ing and products is presented dryer and from there to oil in the booklet, “Corn Starch,” recovery facilities. Washings from the Corn Refiners Asso- from the germ are piped to ciation. the starch centrifuges. Heavy fractions from the coarse A large fraction of total corn- grinding mills and germ sepa- starch production is utilized in rators are passed through fine the manufacture of nutritive grinding mills and washing sweeteners. These starch con- screens for fiber separation. version products include Finally, the slurry is sent to maltodextrins; high fructose, high maltose, and other types centrifuges for separation of of corn syrups; corn syrup gluten (light phase) from solids; and dextrose. Compre- starch (heavy phase). hensive information about these products is presented in The gluten fraction passes to a “Nutritive Sweeteners from centrifugal concentrator and is Corn” available from the Corn filtered and dried. The starch Refiners Association. Another stream goes to washing cy- major use of cornstarch is as a clones fed with fresh water; feedstock for production of overflow, containing residual ethanol and other fermentation gluten from the “mill starch,” products for food and feed is recycled to the starch centri- applications. fuge; underflow from the washing cyclones, a suspen- The corn wet milling process is sion of starch containing only very efficient resulting in the about 0.3 percent protein, is utilization of virtually all of passed through a concentrator the corn kernel. Steepwater, and dryer, from which the bran and gluten from starch finished starch product production and germ meal emerges. from the oil extraction process

8 are all utilized in high-quality REFINING livestock feeds. Manufacture, Crude corn oil, because of the composition and uses of these natural antioxidants it con- feed products are the subject tains, undergoes little deterio- of another Corn Refiners As- ration when stored for long sociation booklet, “Corn Wet periods, provided the tem- Milled Feed Products.” perature is kept well below CORN OIL 40°C (102°F) and moisture plus volatile matter level is MANUFACTURING below 0.4 percent. Since vir- PROCESS Corn germ contains about 85 tually all refined corn oil is percent of the total oil of the utilized in foods, the need to kernel. The rest is dispersed attain a quality suited to such in endosperm and hull frac- use guides the refining pro- tions and is generally utilized cess. Steps include degum- in feed products. The clean, ming to remove phosphatides, dried germ from wet milling alkali treatment to neutralize has an oil content of 45 to 50 free fatty acids, bleaching for percent. Oil is usually ex- color and trace element re- tracted from the germ by a moval, winterization (the re- combination of expelling in moval of high-melting waxes) continuous screw presses and and deodorization (steam stripping under vacuum). Fig- solvent extraction of the press ure 3 is a flow chart of the cake. The initial expeller can refining operations. Crude oil recover a little more than half enters the process via prelimi- of the oil and subsequent nary filtration. Degumming solvent extraction (with hex- removes phosphatides and ane or iso-) will bring other materials that may be the total yield to about 95 precipitated or dissolved from percent. The solvent is re- the crude oil by hot water. moved by evaporation, recov- This step is usually omitted in ered and re-used. The ex- refineries that process only pelled and solvent-extracted corn oil, but is used in refiner- fractions are combined as ies that are set up to refine total crude corn oil. The oil- as well as corn oil. depleted germ is freed of Degumming is accomplished solvent, toasted, ground and by introducing hot water at a screened. The resulting corn level of 1 to 3 percent of oil germ meal is combined with volume, or by injecting an fiber and concentrated equivalent amount of steam steepwater to produce corn to hydrate the phosphatides. gluten feed. The phosphatides, together

9 with certain other materials, clays that bleach by adsorbing absorb water and precipitate color bodies, residual from the oil as a heavier and metal complexes from the phase, which is removed by oil. In plants producing par- centrifugation. tially hydrogenated oil along with regular corn oil, bleached When degumming is omitted, oil coming from the filter is the refiner depends on an alkali piped to the hydrogenation refining step, which uses vessel. When that process is roughly the same temperature completed, the partially hydro- as a degumming operation, to genated oil is passed through take out the phosphatides a filter to remove catalyst along with the free fatty acids particles and other extraneous (in the form of soapstock) and material. Further bleaching, to reduce color. Phospholip- deodorization and filtration ids, “corn lecithin,” can be yield a clear, pale yellow oil. recovered from both degum- ming and alkali refining resi- Refining of the unmodified dues. oil continues with winteriza- tion. Waxes, present in the oil In the alkali refining step, free in small amounts characteristi- fatty acids are neutralized by cally have high melting points treatment at 82 – 100°C (160 – and are readily crystallized by 180°F) with a small amount of chilling in refrigerated vessels. concentrated sodium hydrox- They are then removed by ide solution. Alkali refining filtration. This produces a reduces color and also removes haze-free finished oil when other non-triglyceride sub- refrigerated. stances, which are separated along with the neutralized free Finally, deodorization is ac- fatty acids and hydrated phos- complished by a continuous phatides, by centrifugation. steam distillation under high The alkali treated oil is usually vacuum at high temperature washed with a small quantity 232 – 260°C (450 – 500°F). of hot water to remove re- Oil is fed into the top of the sidual formed by the distillation tower, while a jet alkali treatment. The separated of steam entering at the base residues from alkali treatment carries the volatile odorants are sold as soapstock or acidu- with it as it passes upwards lated soapstock, which con- and exits near the top. Con- tains about 95 percent free densed exhaust steam con- fatty acids. tains odor, color, flavor com- ponents and the remaining The oil is then decolorized by traces of free fatty acids. The treatment with acid-activated deodorized oil is drawn off at

10 Figure 3. Corn Oil Refining Crude Corn Oil ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

Lecithin, etc. Oil ○○○○○○○○ Filter ○○ ○○○○○

Centrifuge○○○○○○○○○○○○○○○○Degumming ○○

○○○○○○○○○○○○○○○○○Alkali Refining ○○○○○○○○ Re-Wash ○○ ○○ Oil Soapstock

○○○○○○○○○○○○○○○○○○Centrifuge Free Fatty Acids Pholpholipids Color

Bleaching

Oil Spent Clay Hydro- ○○○○○○○○○○○○○○○○○○○ Filter Soap genation ○○○○○○○○○○○○○○○○○○○○○○○○○○○○ Phospholipids Color ○○○○○○

○○○○○○○○Filter

○○ Winterize

Residue

Spent Catalysts, Post Bleach Filter ○○○○○○○○ Waxes etc.

Steam Filter ○○○○○○○ Deodorize Condensate Odor Color Flavor Deodorize Polish Filter Free Fatty Acids

Polish Filter

Finished Finished Hydrogenated Oil Oil

11 the bottom of the tower, then The changes in composition dried and passed through a accomplished by refining are polish filter to become the indicated in Table 2. Refining final product, refined corn oil. increases purity from 95 – 96 percent to about 99 percent Corn oil may be shipped from triglycerides. The substances refinery to a food manufac- removed in attaining this level turer after bleaching and win- of purity are ones that detract terization, leaving deodoriza- from the value as a high-qual- tion to be done in the food ity edible oil for varied uses. plant. Essential aspects of Free fatty acids lower the corn oil manufacture are com- of oils in mon throughout the industry, operations. Phospholipids at but the refining process may the levels ordinarily found in vary considerably or have crude oils must be removed some steps eliminated, de- because they produce dark pending on quality and com- colors upon heating the oil position of the crude oil, sta- and form a precipitate, or tus of plant equipment and sludge, in the presence of the planned end use. With small amounts of moisture in current technology, manufac- frying vats. They also signifi- turing is essentially a continu- cantly affect flavor if not re- ous process. moved. Color, odor, and

Table 2. Typical Value, % Comparative Composition of Crude Refined Crude & Refined Corn Oil* Triglycerides 95.6 98.8 Free fatty acids 2.5 0.05 Phospholipids 1.5 0.0 Unsaponifiables Cholesterol 0.0 0.0 1.2 1.1 Tocopherols 0.12 0.08 Waxes 0.01 0.0 Color variable: very pale yellow dark to yellow Odor and flavor strong slight corn corn/feed slight nutty/ buttery Cold test at 0°C (32°F) — clear for 24 hours**

*Adapted and updated from Blanchard, Paul Harwood, “Technology of Corn Wet Milling and Associated Processes,” 1992. Table 14.1, p. 360 **Time may vary depending on producer

12 flavor must be removed be- adequate shelf life, consumer cause of consumer prefer- packages of corn oil are often ence. In addition, these refin- filled under nitrogen into either ing steps solve important glass or plastic bottles. Like- safety concerns with smoking wise, snack foods fried in corn oils and will remove potential oil can be given added protec- contaminants, which may be tion against rancidity by pack- present in any agricultural raw aging in laminated foil and plas- material. Processing is con- tic bags that, in filling and trolled to retain the toco- sealing, have air in the package PACKAGING, pherols in the refined oil. displaced by an inert gas such TRANSPORT, This is an advantage because as nitrogen. Storage at ambi- AND STORAGE of their antioxidant activity, ent room temperature or lower which helps retard develop- is also necessary to prevent de- ment of rancidity, and for the terioration in packaged pre- activity of certain pared foods containing polyun- tocopherols. saturated oils.

Corn oil has little or no sensi- Crude corn oil in bulk — mov- tivity to indoor, incandescent ing between plants, from starch light, but prolonged exposure to plant to a distant refinery or to fluorescent lighting may result an export terminal — is shipped in development of measurable in rail tank cars or, sometimes, rancidity. The consumer pack- in highway tankers. Food grade, ages of clear glass or plastic fully refined corn oil in bulk is now used permit color and clar- often shipped from refinery to ity of the product to be easily food manufacturer in highway seen for the relatively brief pe- tankers, depending on the quan- riod it usually remains on an tity and distance. Smaller quan- open shelf. Contact with cop- tities of corn oil are shipped per promotes the rapid devel- from refinery or repacker to the opment of rancidity in polyun- user in drums or cans. Larger saturated oils. For this reason, quantities, which are shipped metal drums, plant storage for export, are carried by ocean- tanks, rail and highway trans- going parcel tankers. port tanks, valves, piping and process equipment must be Although corn oil in packaged scrupulously free of copper at products is well protected all places where there could be against rancidity by the natural any contact with the oil. Pro- antioxidants it contains, further longed contact with iron may protection by displacing also cause problems, but iron is headspace air with nitrogen is of much less concern in this re- sometimes practiced. To ensure gard than copper. 13 Physical and chemical data on fined stages or in the finished vegetable oils serve a number of (fully refined) form. Tables 3 practical uses: assessment of through 5 present data concern- nutritional values; specification ing the physical and chemical writing for sale and purchase of properties of finished (fully re- oils, in consideration of intended fined) corn oil. use; quality control and monitor- ing of refining and food manu- Table 3 represents the infor- PHYSICAL AND facturing processes; background mation on refined corn oil CHEMICAL information for chemical, bio- that is of primary concern to PROPERTIES logical and medical research in- nutritionists and dieticians. volving fats; and regulation of Table 4 lists the primary speci- food quality and safety by pub- fications for corn oil that have lic agencies charged with that re- been adopted by the Commit- sponsibility. tee on Food Chemicals Codex of the National Academy of Corn oil may be supplied to the Sciences/National Research user in the crude state for fur- Council. Purchase specifica- ther refining, in intermediate re- tions for crude and refined

Table 3. (Amount in 100 Grams of Oil) Approximate Composi- Weight (grams) 100.0 tion of Refined Corn Oil: Moisture (grams) None Nutrient Values Protein (N x 6.25) (grams) None Fat, Total (grams) 100.0 Triglycerides (grams) 98.8 Polyunsaturates, Total (grams) 59.7 Cis, Cis Only (grams)* 58.7 Monounsaturates (grams) 26.0 Saturates, Total (grams)* 13.1 Unsaponifiable Matter (grams) 1.2 Cholesterol (milligrams) None Phytosterols (milligrams) 1000 Tocopherols, Total (milligrams) 88 Alpha-tocopherol (milligrams) 19 Gamma-tocopherol (milligrams) 67 Delta-tocopherol (milligrams) 3 Carbohydrate, Available (grams) None Ash (grams) None Sodium (milligrams) None Energy (calories) 885

*Polyunsaturated and saturated fats as defined for nutrition information labeling, 21 CFR 101.9 (1994).

14 corn oil may be obtained from characterize edible oils, pre- individual oil producers. Ad- senting ranges that typify re- ditional chemical and physical fined corn oil, are shown in measurements that are used to Table 5.

Table 4. Arsenic Not more than 0.5 mg/kg Food Chemicals Codex Color (AOCS-Wesson) Not more than 5.0 red Specifications for Refined Free Fatty Acids (as ) Not more than 0.1% 120 - 130 Corn Oil Lead Not more than 0.1 mg/kg Linolenic Acid Not more than 2.0% Peroxide Value Not more than 10 meq/kg Unsaponifiable Matter Not more than 1.5% Water Not more than 0.1%

Food Chemicals Codex, Fifth Edition, pp. 122-123, National Academy Press, 2003.

Iodine Value (Wijs) 122 – 131 Table 5. 189 – 195 Typical Chemical and Viscosity (Sayboldt-Universal, 100°F) 165 – 175 seconds Physical Data for Refractive Index @ 25°F 1.470 – 1.474 Refined Corn Oil Specific Gravity @ 60°F 0.922 – 0.928 Weight per gallon @ 60°F 7.7 pounds Melting Point 12 – 17°F Smoke Point 445 – 460°F Flash Point 630 – 640°F Fire Point 690 – 700°F Cloud Point 7 – 12°F

Typical Profile Grams/100 gm. oil

Linoleic 18:2 (polyunsaturated) 54 – 60 Linolenic 18:3 (polyunsaturated) 1 Palmitic 16:0 (saturated) 11 – 13 Stearic 18:0 (saturated) 2 – 3 Oleic 18:1 (monounsaturated) 25 – 31

15 ROLE OF CORN OIL IN The National Research Council THE DIET and the Food and Agriculture Corn oil can play a major role in Organization/World Health Or- the human diet. It is a concen- ganization recommend about 2- trated source of energy (calo- 4 percent energy in the form of ries), is very digestible, provides essential fatty acids with an ad- essential fatty acids and Vitamin ditional 3 percent of energy for E, and is a rich source of poly- women who are pregnant or are NUTRITIONAL unsaturated fatty acids, which breast feeding. A tablespoon PROPERTIES help regulate blood cholesterol serving of corn oil will satisfy the levels and lower elevated blood daily essential fatty acid require- pressure (1,2). Animal and hu- ment for a healthy child or adult. man studies show that at least 97 percent of the oil is digested LABELING and absorbed. Like all fats and A typical Nutrition Facts panel oils, corn oil provides 9 kcal (38 for corn oil is shown in Figure kjoules)/gram, or about 120 kcal 4. Corn oil may be labeled “A per one tablespoon (14g) serv- cholesterol and/or sodium free ing. Corn oil is a rich source of food.” When this descriptor is , an essential fatty used the following statement acid that the body cannot make. must appear: “Contains 14

Figure 4. Nutrition Facts Nutritional Labeling of Serving Size 1 tbsp (14 g) Corn Oil Servings Per Container (pint) 32

Amount Per Serving Calories 120 Calories from Fat 120 %Daily Value* Total Fat (14 g) 22% (2 g) 9% Polyunsaturated Fat (8 g) Monounsaturated Fat (4 g) Cholesterol (0 mg) 0% Sodium (0 mg) 0% Total Carbohydrate (0 g) 0% Protein (0 g) Vitamin E 15%

Not a significant source of dietary fiber, sugars, vitamin A, vitamin C, calcium, and iron. *Percent Daily Values are based on a 2,000 calorie diet. Ingredients: Corn Oil

16 grams of fat per serving. See Nu- because corn oil was the trition Facts panel for information only highly polyunsaturated on total fat, saturated fat and other oil readily available to inves- nutrients.” tigators and patients in the mid-1950s. Due to its high stability, pleasant taste and CHOLESTEROL AND multifunctional usage, corn CORONARY HEART DISEASE oil became the standard The relationship between dietary against which other oils fat, blood cholesterol and lipo- were compared to assess protein levels and coronary cholesterol-lowering abilities heart disease has been exten- of oils. In a survey of the sively studied for fifty years. It literature, 30 clinical studies is now widely accepted that a (39 diet comparisons) were diet high in saturated fat and found where corn oil was a cholesterol is one of many caus- significant part of the diet. ative factors in the development A total of 1,160 subjects of atherosclerosis and coronary were studied; the average heart disease. Regression equa- cholesterol lowering was 16 tions relating type of fat and its percent. This is greater effect on blood cholesterol, than the 3-14 percent cho- based on 248 metabolic diet lesterol lowering anticipated comparisons (3), show that satu- by the National Cholesterol rated fats raise, polyunsaturated Education Program. Simi- fats lower and monounsaturated lar benefits are not likely to fats have no effect on blood result for the general popu- cholesterol levels. Saturated fats lation as diets are strictly are approximately twice as pow- controlled in clinical trials. erful in raising cholesterol levels However, the level of total as polyunsaturated fats are in and saturated fat and cho- lowering them. The National lesterol in the diet has Cholesterol Education Program steadily decreased over the and the American Heart Asso- past 10 to 15 years. ciation recommend a diet in which total fat is less than 30 In research where corn oil percent of calories, saturated fat was compared to other oils, is less than 10 percent of calo- nine human feeding studies ries, polyunsaturated fat is up to involving 391 men and 10 percent of calories and cho- women showed that corn lesterol is 300 mg or less per day. oil had the greatest choles- terol-lowering abilities. In Corn oil has been used exten- fact, three studies show sively in research studying the corn oil to be superior to relationship of dietary fat to in overall cho- blood cholesterol levels. This is lesterol lowering. The total 17 composition of an oil, which directly below the saturated fat includes the fatty acid compo- line on the Nutrition Facts sition, triglyceride structure panel. Items containing less and non-triglyceride compo- than 0.5 grams of trans fat per nents, contributes to that oil’s serving can be declared as 0 ability to lower serum choles- grams. If the food contains terol. Among liquid vegetable less than 0.5 grams of total fat, oils, no oil is better than corn a footnote can replace the trans oil to lower blood cholesterol line that says, “Contains an levels. insignificant amount of trans fat.” Items that have levels of BLOOD PRESSURE less than 0.5 grams per serving Numerous human studies of both saturates and trans fat show that diets enriched in can bear the statement, “Satu- polyunsaturated fatty acids rated fat free.” Items that offer can significantly lower el- a 25 percent reduction in satu- rates per serving can bear the evated blood pressure. Corn statement, “Reduced satu- oil was used in many of these rates.” studies (4). Corn oil diets have shown blood pressure The average trans fatty acid lowering of about 12 percent intake is estimated at 2-4 per- in men and 5 percent in cent of the total energy con- women who had elevated sumed. The average saturated blood pressure (mild hyper- fat intake estimate is 12-14 tension). No significant effect percent. Current dietary ad- of polyunsaturates has been vice is to reduce consumption noted in persons with normal of both saturated and trans blood pressure. fatty acids.

TRANS FATTY ACIDS Where do trans fatty acids The Food and Drug Admin- come from? Trans fatty acids istration adopted regulations occur naturally in ruminant that require the labeling of animals, such as cows. retail foods for trans fatty and milk fat can contain be- acids in January 2006. The tween four and 11 percent trans primary reason for this re- fatty acids. In vegetable oil quirement is the fact that processing, most trans fatty numerous studies have shown acid formation occurs during that, like saturated fatty acids, partial hydrogenation. Partial trans fatty acids elevate blood hydrogenation of liquid veg- cholesterol levels. (5) etable oils to produce more solid and stable forms for use The requirement mandates a in products such as marga- separate line item for trans fat rines and has

18 been carried out for over 90 CORN OIL PRODUCTION years. During hydrogenation, The amount of corn oil pro- some of the naturally occur- duced, which is controlled by ring cis double bonds in the the total volume of corn pro- unsaturated fatty acids are cessed, has increased steadily changed into trans double since 1973. Between 1956 and bonds, which makes the fatty 1974, average annual growth acid molecule appear and act in production of crude corn PRODUCTION similarly to that of a saturated oil was 3.2 percent. From AND fatty acid. Small amounts of 1974 through 2002, the rate trans fatty acids, typically 0.5 – of increase climbed to 5.75 COMMERCIAL 3 percent, are also formed percent annually. USES during deodorization of non- hydrogenated salad oils. This Corn oil is now the second is the final step in oil process- leading vegetable oil produced ing where the oil is exposed to in the United States, second in high temperature. importance only to soybean oil. Domestic corn oil pro- 1. B.F. Hauman, Corn Oil. J. duction was 2.5 billion pounds Am. Oil Chem. Soc. 62:1524- in 2004 and soybean oil, 31, 1985 which has dominated the U.S. 2. J. Dupont, P.J. White, M.P. vegetable oil market was 18.7 Carpenter, E.J. Schaefer, S.N. billion pounds. Relative pro- Meydani, C.E. Elson, M. duction of major vegetable Woods and S.L. Gorbach, oils is shown in Table 6. Food uses and health effects of corn oil. J. Am. Col. Nutr. Vegetable oil statistics are avail- 9:438-470, 1990 able online from the U. S. De- partment of Agriculture Eco- 3. D.M. Hegsted, L.M. Ausman, nomic Research Service at J.A. Johnson and G.E. Dallal, Dietary fat and serum ; http://usda.mannlib.cornell.edu/ an evaluation of the experi- data-sets/crops/89002/. mental data. Am. J. Clin. Nutr. 57:875-883, 1993 Table 6. 4. J.M. Iacono and R.M. Soybean Oil 18,710 Vegetable Oil Production, 2004 Dougherty, Effects of poly- Corn Oil 2,470 (Million Pounds) unsaturated fats on blood 915 pressure. Ann. Rev. Nutr. 13:243-260, 1993 Sunflower Oil 305 626 5. J.T. Judd, D.J. Baer, B.A. Clevidence, P. Kris-Etherton, Source: Bureau of the Census and R.A. Muesing and M. Iwane. Agricultural Marketing Service Lipids 37, no2: 123-131, 2002

19 FOOD USE OF ety of packaged and restau- VEGETABLE OILS rant foods, including: Overall the major vegetable „ oils such as soybean, corn, Spaghetti sauce; „ cottonseed, and canola com- Potato chips and snack prised more than 95 percent foods; „ of the vegetable oil consumed French fries and breaded in the United States in 2004. fried foods; „ The vast majority of this use Baking mixes; „ is in three categories: (1) salad Frostings and whipped or which takes toppings; „ around 47 percent of domes- Crumb coatings for meat tic consumption; (2) shorten- and ; and „ ing (fluid, semi-solid, or solid Baked goods. baking and frying fats) which accounts for about 43 percent Only a minor amount of total of domestic vegetable oil corn oil production is blended consumption; and (3) marga- with other vegetable oils with rine which accounts for about the exception of corn oil in 10 percent of domestic veg- consumer packages such as etable oil consumption. those listed above in which ingredient statements show corn oil as part of a blend or FOOD USES OF CORN OIL one of several optional oils The principal food uses of that may be used. There are a corn oil (as either consumer few such products that indi- or institutional products) in- clude: cate only corn oil is used. Use in packaged foods represents „ Salad and cooking oil - 100 a small fraction of total corn percent corn oil or in oil consumption. blends with other liquid vegetable oils. The output of cooking oil is „ – both 100 per- divided between consumer cent corn oil in the oil and institutional packaged phase or in blends with products and industrial frying other vegetable oils. oils furnished to snack food „ Blends of (40 per- producers and restaurant fry- cent) and corn oil marga- ing operations. Corn oil may rine (60 percent). be blended with other oils in „ Mayonnaise and emulsion- packages for home use in type salad dressings. order to provide desirable flavor to other oils. Institu- As an oil ingredient in a vari- tional frying use of corn oil

20 has expanded dramatically in plies have been diverted to the last decade as fast food institutional frying uses. companies have switched potato frying from an animal INDUSTRIAL USE OF fat to a vegetable oil base. CORN OIL Historically, both non-hydro- Consumption of corn oil in genated and partially hydroge- nonfood uses represents a nated corn oil have been used negligible percentage of total for frying applications. Re- consumption. Small amounts cently, the use of non-hydro- are used in the manufacture genated corn oil has increased, of resins, plastics, lubricants primarily to address trans fatty and similar oils. A small acid concerns. quantity of highly refined oil is used by the pharmaceutical Margarine began to displace industry in certain dosage butter as a household spread forms and for other purposes. beginning in the 1930s. How- ever, before 1950, use of corn The residues and byproducts oil in margarine manufacture from corn oil refining amount was minimal. The discovery to 8 to 10 percent of the in the 1950s that corn oil had crude oil entering the process. a favorable impact on serum The bulk of these residues are cholesterol dramatically ex- in the form of soapstock, panded its use in margarine. which contains the neutralized Corn oil are free fatty acids and phosphati- among the highest in des. Most materials recovered polyunsaturates of all the from soapstock have indus- leading margarines. Use of trial end uses, but oil can be a corn oil in margarine was only source of edible forms of free about one million pounds in fatty acids and lecithin. It is the 1930s, but increased to possible to recover small around 15 million pounds in quantities of phytosterols and the 1950s, 50 million pounds other substances from in the 1960s and up to 250 soapstock and the minor resi- million pounds in the early dues. Recovered waxes from 1980s. Corn oil use for marga- the winterizing step are uti- rine production has decreased lized industrially or in animal since the early 1980s as sup- feeds.

21 Published literature provides numerous sources and de- scriptions of methods of analysis for various chemical and physical properties of corn and other food oils. The Corn Refiners Association has ANALYTICAL developed various analytical EXAMINATION methods for numerous prod- OF CORN OIL ucts of the corn wet milling industry, including corn oil.

These “Standard Analytical Methods” are published by the Association and may be obtained for a reasonable cost. Methods developed specifically for use with corn oil are:

„ H-10: Cold Test „ H-12: Color (Spectropho- tometric) „ H-22: Free Fatty Acids „ H-32: Iodine Number (Wijs Method)

In addition, a number of other professional societies publish methods that may be of use to the producer and user of corn and other veg- etable oils. In particular, the reader is referred to the meth- ods published by the AOAC International (2200 Wilson Blvd., Suite 400, Arlington, Virginia 22201, www.aoac.org) and the American Oil Chem- ists’ Society (P.O. Box 3489, 1608 Broadmoor Drive, Champaign, Illinois 61826, www.aocs.org).

22 Corn Refiners Association 1701 Pennsylvania Avenue, N.W. • Washington, D.C. 20006-5805 202-331-1634 Fax: 202-331-2054 • www.corn.org