Chemical composition is not a grade factor but it provides additional information related to nutritional value for livestock and poultry feeding and for wet milling uses, as well as other processing uses of corn. Unlike many physical attributes, chemical composition values would not be expected to change significantly during storage or transport. Corn consists primarily of protein, starch and oil, composition components that are of significant interest to the industry.
Protein is very important for poultry and livestock feeding. It helps with feeding efficiency and supplies essential sulfur-containing amino acids. Protein is usually inversely related to starch content. Results are reported on a dry basis.
- In 2011, the U.S. Aggregate protein averaged 8.7%.
- Protein ranged from 6.7% to 12.5% with a standard deviation of 0.60% for U.S. Aggregate.
- Protein was distributed with 41.8% between 8.0% to 8.99% and 34.0% between 9.0% to 9.99%.
- Protein averages for corn expected to go to the Gulf, Pacific Northwest, and Southern Rail regions were 8.7%, 8.5%, and 9.1%, respectively
Starch is an important factor for corn used by wet millers and drygrind ethanol manufacturers. High starch content is often indicative of good kernel maturation/filling conditions and reasonably high kernel densities. Starch is usually inversely related to protein content. Results are reported on a dry basis.
- The U.S. Aggregate starch averaged 73.4%.
- Starch ranged from 71.5% to 75.4% with a standard deviation of 0.62% for the U.S. Aggregate.
- The majority of the samples had a starch concentration in the 73.0% to 73.99% range.
- Starch averages for corn expected to go to the Gulf, Pacific Northwest, and Southern Rail regions were 73.5%, 73.6% and 73.1%, respectively.
Oil is an essential component of poultry and livestock rations. It serves as an energy source, enables fat-soluble vitamins to be utilized, and provides certain essential fatty acids. Oil is also an important byproduct of corn wet and dry milling. Results are reported on a dry basis.
- U.S. Aggregate oil averaged 3.7%.
- Oil ranged from 2.0% to 5.0% with a standard deviaton of 0.31% for the U.S. Aggregate.
- Oil was distributed with 46.6% of the samples at 3.25% to 3.74%, and 38.2% of samples at 3.75% to 4.24%.
- Oil averages for corn expected to go to the Gulf, Pacific Northwest, and Southern Rail regions were 3.7%, 3.6% and 3.7%, respectvely. Thus, there is likely no noteworthy diﬀerences in oil content of corn expected to go to any of these catchment areas.
Chemical Composition Summary
- In addition to genetics, the average protein content (8.7%) is affected to some extent by crop yields (bushels per acre) and available nitrogen during the growing season.
- Starch content (73.4%) was relatively high which in combination with observed high test weights indicates good kernel filling that should be good for all processing uses and feeding.
- Oil content (3.7%) was relatively constant across all export catchment areas.