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2015/2016 Sorghum Early Harvest Report

Contents

  1. Harvest Quality Highlights
  2. Introduction
  3. Quality Test Results
  4. Chemical Composition
  5. Physical Factors
  6. Testing Analysis Methods
  7. Moisture
  8. Chemical Composition
  9. Physical Factors
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C. Chemical Composition

Chemical composition of sorghum is important because the components of protein, starch, oil and tannins are of significant interest to end users. The chemical composition attributes are not grade factors. However, they provide additional information related to nutritional value for livestock and poultry feeding and other processing uses of sorghum. Unlike many physical attributes, chemical composition values are not expected to change significantly during storage or transport.

SUMMARY: CHEMICAL COMPOSITION

  • In 2015, Early Harvest protein concentration averaged 10.4%, which is on the lower end of typical protein concentration values in literature for U.S. sorghum hybrids.
  • Early Harvest starch concentration averaged 73.3% in 2015, a typical level for any sorghum samples.
  • Early Harvest oil concentration averaged 4.3% in 2015, which is on the higher end of typical oil concentration values in literature for U.S. sorghum hybrids.
  • Early Harvest oil concentration in 2015 was bimodally distributed with 40% of samples at 3.99% or lower and 50% of samples at 4.5 to 4.99%.
  • All 2015 Early Harvest samples were considered tannin-free.

1. Protein

Protein is very important for poultry and livestock feeding. It supplies essential sulfur-containing amino acids and helps to improve feed conversion efficiency. Protein is usually inversely related to starch concentration. Results are reported on a dry basis.

RESULTS

  • In 2015, Early Harvest protein concentration averaged 10.4%, which is on the lower end of typical protein concentration values in literature for U.S. sorghum hybrids.
  • The protein concentration values for the 2015 Early Harvest samples had a standard deviation of 0.75%. Protein concentration range for the Early Harvest samples was from 7.1 to 12.7% in 2015.
  • Protein concentration in the 2015 Early Harvest samples was distributed with 20% of samples below 9.0%, 54% between 9.0 and 10.99%, and only 26% at or above 11.0%.

2. Starch

Starch is an important factor for sorghum related to metabolizable energy for livestock and poultry. Levels of starch in sorghum may also be of interest to processors as starch provides the substrate for several valueadded processes. High starch concentration is often indicative of good kernel maturation/filling conditions and reasonably moderate kernel densities. Starch is usually inversely related to protein concentration. Results are reported on a dry basis.

RESULTS

  • Early Harvest starch concentration averaged 73.3% in 2015, a typical level for any sorghum samples.
  • The starch concentration values for the 2015 Early Harvest samples had a standard deviation of 0.69%.
  • Starch concentration range for the Early Harvest samples was from 71.1 to 75.0% in 2015.
  • Starch concentration in the 2015 Early Harvest samples was distributed with 26% of samples between 70.0 and 72.99%, 48% between 73.0 and 73.99%, and 26% equal to or greater than 74.0%.

3. Oil

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 may also be an important co-product of sorghum value-added processing. Results are reported on a dry basis.

RESULTS

  • Early Harvest oil concentration averaged 4.3% in 2015, which is on the higher end of typical oil concentration values in literature for U.S. sorghum hybrids.
  • The oil concentration values for the 2015 Early Harvest samples had a standard deviation of 0.31%.
  • Oil concentration range for the Early Harvest samples was from 3.0 to 5.0% in 2015.
  • Early Harvest oil concentration in the 2015 Early Harvest samples was bimodally distributed with 40% of samples at 3.99% or lower and 50% of samples at 4.5 to 4.99%. Additionally, 8% of samples had oil concentrations from 4.0 to 4.49% and 2% were at 5.0% and higher.
  • The samples with oil concentrations greater than 4.25% were confined to one area within the Early Harvest sampling area.

4. Tannins

Tannins are present in sorghum varieties that have a pigmented testa within their kernels. Chemically, tannins are compounds that are large molecules comprised of smaller molecules (catechins and epicatechins) and belong to a broader class of compounds called proanthocyanidins (compounds found in grapes, bark, tea leaves, etc. that influence aroma, flavor, mouth-feel and astringency, and have antioxidant and other possible health benefts). While present in sorghum varieties grown around the world, more than 99% of sorghum currently grown in the United States is tannin-free due to decades of breeding efforts to eliminate tannins from sorghum hybrids. Tannins have effects on nutritional and functional properties as a result of interactions of the tannins with other kernel chemicals. Livestock and poultry growth performance is negatively affected by presence of tannins in sorghumcontaining rations. Current non-tannin sorghums grown in the United States have virtually the same energy profile as corn in feed rations. Results are reported as being below 4.0 milligrams of catechin equivalents (CE) per gram sample or 4.0 mg CE/g or above. Values below 4.0 mg CE/g generally imply absence of condensed tannins1, 2.

RESULTS

  • All observed tannin levels in the 2015 Early Harvest samples were less than 4.0 mg CE/g, implying an absence of tannins.

1Awika, J.M., L.W. Rooney, 2004. Sorghum phytochemicals and their potential impact on human health. Phytochemistry 65, 1199-1221.

2Price, Martin L., Van Scoyoc, S., Butler, L.G., 1978. A critical evaluation of vanillin reaction as an assay for tannin sorghum. Journal of Agricultural and Food Chemistry 26, 1214-1218.