Course:Grain Quality

1
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy
Rice Exercise
INFORMATION COLLECTION
Characteristic Sample 1 Sample 2 Sample 3 Average
Moisture content
Oven
Meter
Grain dimensions LW
1000-grain weight gm
Degree of dockage
Inert
Weeds
Insects
Cracked grains
Discolored grains
Immature grains
2
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice
Lesson 1 The quality characteristics
3
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
1 The quality characteristics
PADDY CHARACTERISTICS
List of characteristics 1. 2. 3. 4. 5.
6. 7. 8. 9. 10.
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
1 The quality characteristics
QUALITY CHARACTERISTIC MOISTURE CONTENT
Moisture content has a significant influence on
all aspects of paddy quality. To obtain high
yields, it is essential that paddy be milled at
the proper moisture content. Paddy is at its
optimum milling potential when its moisture
content is 14
5
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
1 The quality characteristics
QUALITY CHARACTERISTIC IMMATURE
Immature rice kernels are very slender and chalky
and result in the production of excessive bran,
broken grains and brewers rice
6
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
1 The quality characteristics
QUALITY CHARACTERISTIC VARIETAL PURITY
A mixture of varieties in a sample of paddy
causes difficulties in milling and usually
results in reduced milling capacity, excessive
breakage, lower milled rice recovery, and reduced
head rice yields.
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
1 The quality characteristics
QUALITY CHARACTERISTIC DOCKAGE
Dockage includes chaff, stones, weed seeds, soil,
rice straw, stalks and other foreign matter.
These impurities generally come from the field or
from the drying floor.
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
1 The quality characteristics
QUALITY CHARACTERISTIC DISCOLORED
Water, insects and heat exposure can cause paddy
to deteriorate through biochemical changes in the
grain which may result in the development of
off-doors and changes in physical appearance
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
1 The quality characteristics
QUALITY CHARACTERISTIC CRACKED
Overexposure of mature paddy to fluctuating
temperature and moisture conditions leads to the
development of crack in individual kernels.
10
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
2 Measuring moisture content
OVEN METHOD
This method weighs a sample of the paddy and then
removes all the moisture by heating the sample in
an oven. After the moisture has been removed, the
sample is re-weighed.
11
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
2 Measuring moisture content
MOISTURE METER
This method weighs a sample of the paddy and then
removes all the moisture by heating the sample in
an oven. After the moisture has been removed, the
sample is re-weighed.
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice
Lesson 3 Measuring grain dimension and
varietal purity
VARIETAL PURITY

• Crops of a single variety are easier to manage
  because they
• have uniform stands
• fill uniformly
• ripen at the same time

• Milling a mixture of varieties results in
• reduced milling capacity
• excessive breakage
• lower milled rice recovery
• reduced head rice yields

A measure of varietal purity is the L-W ratio of
the grain
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
3 Measuring grain dimension and varietal purity
Grain Length (mm) Width(mm)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Total
Average total/20 A B
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
3 Measuring grain dimension and varietal purity
REVIEW
1.
2
3.
4.
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
3 Measuring 1000-grain weight
1000-GRAIN WEIGHT

• Procedure
• Count 1000 grains of paddy.
• Weigh the 1000 grains.
• This is the 1000-grain weight.

16
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
4 Measuring the amount of dockage
PADDY PURITY - DOCKAGE

• Procedure
• Weigh a sample of paddy (about 100gm) A.
• Separate the dockage from the paddy.
• Weigh the dockage B.

Dockage in a paddy rice sample less is better.
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Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice
Lesson 4 Measuring the amount of dockage
DOCKAGE TYPES

• Procedure
• Weigh a sample of paddy (about 100gm) A.
• Separate the insects from the paddy.
• Separate the weed seed from the paddy.
• Separate the inert material from the paddy.
• Weigh the types of dockage B, C, and D.

18
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
5 Measuring the percentage of cracked grain
CRACKED GRAIN PERCENTAGE
Crack detector

• Procedure
• Select a sample of about 25gm of paddy and weigh
  it A.
• Separate the cracked grains from the paddy.
• Weigh the discolored grains B.

19
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
6 Measuring the percentage of immature grain
IMMATURE GRAIN PERCENTAGE

• Procedure
• Select a sample of about 25gm of paddy and weigh
  it A.
• Separate the immature grains from the paddy.
• Weigh the immature grains B.

20
Course Grain Quality Module 3 Determining
the Physical Characteristics of Paddy Rice Lesson
7 Measuring the percentage of discolored grain
DISCOLORED GRAIN PERCENTAGE

• Procedure
• Select a sample of about 25gm of paddy and weigh
  it A.
• Separate the immature grains from the paddy.
• Weigh the immature grains B.

21
Course Grain Quality Module 3 Quality of
paddy Review
QUIZ ANSWERS

• Any four of moisture content. Varietal purity,
  cracked grain, immature or discolored
• Air-oven method, using moisture
• All foreign matter in he paddy sample. Weeds,
  insects, stones, inert
• The length width ratio is used because it
  measures varietal purity
• Yellowing or black spots through change in the