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Physical Properties of Grains

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5. Examine the dockage-free sample for ergot, smut, stones, treated seeds, and odor. 6. Determine the test weight per bushel of the dockage-free sample ... – PowerPoint PPT presentation

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Title: Physical Properties of Grains


1
Lecture 6
  • Physical Properties of Grains
  • Grading of Wheat

2
Gramineae (Poaceae)Grass Family
  • 600 genera, 10,000 species
  • Most common plant family
  • Food plants, ornamentals, forage crops, weeds,
    and even building materials
  • Fruit is called a caryopsis a dry,
    single-seeded, indehiscent fruit in which the
    seed and pericarp are fused

3
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4
Geometrical Properties
  • How do the following properties we talked about
    on Tuesday related to official grading?
  • Shape
  • Size
  • Volume
  • Sphericity
  • Surface Area

5
Class Differences
6
Class Differences
7
Class Differences
8
Class Differences
9
Class Differences
10
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11
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12
Definitions in Wheat
  • Dockage material removed by an approved device
    according to procedures prescribed by FGIS
    typically including weed seeds, weed stems,
    straw, grain other than wheat, sand, dirt, dust
  • Shrunken and broken pass through a 0.064 x 3/8
    slotted sieve
  • Foreign Material insect parts, small seeds,
    stones, and pieces of stems or cobs
  • Damaged Kernels remaining broken pieces, or
    whole kernels that are weather damaged, diseased,
    frost damaged, germ damaged, heat damaged, insect
    bored, mold damaged, sprout damaged, or otherwise
    materially damaged
  • Total defects sum of shrunken broken, foreign
    material, and damaged kernels

13
Wheat Grading Steps
  • Get a 1000 to 1025 g representative sample
  • Examine for heating, odor, filth, castor beans,
    crotalaria seeds, garlic, glass, insect
    infestation, and unknown substances
  • Divide out a 250g (representative portion) and
    determine moisture content, return
  • Determine dockage from whole sample

14
Wheat Grading Steps
  • 5. Examine the dockage-free sample for ergot,
    smut, stones, treated seeds, and odor
  • 6. Determine the test weight per bushel of the
    dockage-free sample
  • 7. When necessary, divide out a representative
    portion and determine the protein
  • 8. Divide out a representative portion (250 g)
    and determine the shrunken and broken kernels

15
Wheat Grading Steps
  • 9. If necessary, divide out representative
    samples from the SHBN-free sample and pick
    percentage of kernel damage (15 g) and foreign
    material (30 g). Damage may include contrasting
    wheat classes, damaged kernels, and heat-damaged
    kernels.

16
Sources of Dockage
  • Harvesting machinery
  • Age, condition, and adjustments
  • Weeds in the field
  • Cropping system
  • Environmental conditions
  • Handling of the material

17
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18
Where would you take a representative sample?
19
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20
Types of Wheat Kernel Damage
21
Kernel Damage
22
Kernel Damage
23
Kernel Damage
24
Kernel Damage
25
NOT Kernel Damage
26
Kernel Damage
27
Kernel Damage
28
Special Grades
29
Special Grades
30
Conclusions
  • Dockage is not an official U.S. grading factor
    but can be specified in a contract
  • Dockage is actually added to wheat during
    blending to just meet the grade requirements!
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