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Corn kernels have threemain parts, the seed coat orpericarp, the starchy endosperm,and the embryo,commonly called the germ(Figure 1).The pericarp is the outerskin or hull of the kernelwhich serves to protect theseed. The endosperm, themain energy reserve, makesup about 80 percent of thetotal weight of the kernel. Itis about 90 percent starchand 7 percent gluten (protein),with the remainderconsisting of small amountsof oil, minerals and sometrace constituents.Typical composition of corngrain is shown in Table 1.The embryo contains a min-Endospermiature plant made up of aroot like portion and five orsix embryonic leaves. Inaddition, there are presentlarge quantities of high energyoil to feed the tiny plantwhen it starts to grow, aswell as many substancesrequired during germinationand early development.StarchStarchandGlutenGermHull andFiberFigure 1.A Kernel of Corn.THE CORNKERNELCharacteristic Range AverageMoisture (% wet basis) 7 – 23 16.0Starch (% dry basis) 61 – 78 71.7Protein (% dry basis) 6 – 12 9.5Fat (% dry basis) 3.1 – 5.7 4.3Ash (oxide) (% dry basis) 1.1 – 3.9 1.4Pentosans (as xylose) (% dry basis) 5.8 – 6.6 6.2Fiber (neutral detergent residue) (% dry basis) 8.3 – 11.9 9.5Cellulose + Lignin 3.3 – 4.3 3.3(acid detergent residue) (% dry basis)Sugars, Total (as glucose) (% dry basis) 1.0 – 3.0 2.6Total Carotenoids (mg/kg) 12 – 36 26.0Table 1.Proximate Analysis ofYellow Dent CornGrainReprinted with permission form White, P.J., and Johnson, L.A., eds., 2003, CornChemistry and Technology, American Association of Cereal Chemists, St. Paul, MN.5