Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceExercise :

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 [%]

INFORMATION COLLECTION

Course : Grain QualityModule 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.

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 1 : The quality characteristics

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%

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 1 : The quality characteristics

QUALITY CHARACTERISTIC: MOISTURE CONTENT

Immature rice kernels are very slender and chalky and result in the production of excessive bran, broken grains and brewer’s rice

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 1 : The quality characteristics

QUALITY CHARACTERISTIC: IMMATURE

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.

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 1 : The quality characteristics

QUALITY CHARACTERISTIC: VARIETAL PURITY

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.

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 1 : The quality characteristics

QUALITY CHARACTERISTIC: DOCKAGE

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

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 1 : The quality characteristics

QUALITY CHARACTERISTIC: DISCOLORED

Overexposure of mature paddy to fluctuating temperature and moisture conditions leads to the development of crack in individual kernels.

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 1 : The quality characteristics

QUALITY CHARACTERISTIC: CRACKED

                           

                                                                                

                                                                                                            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.

OVEN METHOD

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 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.

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 2 : Measuring moisture content

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy Rice Lesson 3 : Measuring grain dimension and varietal purity

A measure of varietal purity is the L-W ratio of the grain

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

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 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]

Average paddy length [A]Average paddy length [B]

Length to width ratio (L/W)

=

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 3 : Measuring grain dimension and varietal purity

REVIEW

1.

2

3.

4.

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 3 : Measuring 1000-grain weight

Procedure

1. Count 1000 grains of paddy.

2. Weigh the 1000 grains.3. This is the 1000-grain

weight.

1000-GRAIN WEIGHT

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 4 : Measuring the amount of dockage

PADDY PURITY - DOCKAGE

Dockage in a paddy rice sample – less is better.

Procedure

1. Weigh a sample of paddy (about 100gm)[A].

2. Separate the dockage from the paddy.3. Weigh the dockage [B].

Wt of dockage [B]

Total wt of sample [A]X 100% Dockage =

Procedure

1. Weigh a sample of paddy (about 100gm) [A].2. Separate the insects from the paddy.3. Separate the weed seed from the paddy.4. Separate the inert material from the paddy.5. Weigh the types of dockage [B], [C], and [D].

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy Rice Lesson 4 : Measuring the amount of dockage

DOCKAGE TYPES

Wt of insects [B]

Total wt of sample [A]X 100% Insects =

Wt of weed seed [B]

Total wt of sample [A]X 100% Weedseed =

Wt of inertmaterial [B]

Total wt of sample [A]X 100% Inertmaterial =

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 5 : Measuring the percentage of cracked grain

Procedure

1. Select a sample of about 25gm of paddy and weigh it [A].2. Separate the cracked grains from the paddy.3. Weigh the discolored grains [B].

Wt of cracked grains [B]

Wt of sample [A]X 100% Cracked grains =

CRACKED GRAIN PERCENTAGE

Crack detector

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 6 : Measuring the percentage of immature grain

IMMATURE GRAIN PERCENTAGE

Procedure

1. Select a sample of about 25gm of paddy and weigh it [A].2. Separate the immature grains from the paddy.3. Weigh the immature grains [B].

Wt of immature grains [B]

Wt of sample [A]X 100% Immature grains =

Course : Grain QualityModule 3 : Determining the Physical Characteristics of Paddy RiceLesson 7 : Measuring the percentage of discolored grain

Procedure

1. Select a sample of about 25gm of paddy and weigh it [A].2. Separate the immature grains from the paddy.3. Weigh the immature grains [B].

Wt of immature grains [B]

Wt of sample [A]X 100% Immature grains =

DISCOLORED GRAIN PERCENTAGE

Course : Grain QualityModule 3 : Quality of paddyReview :

1. Any four of moisture content. Varietal purity, cracked grain, immature or discolored

2. Air-oven method, using moisture3. All foreign matter in he paddy sample. Weeds, insects, stones, inert4. The length width ratio is used because it measures varietal purity5. Yellowing or black spots through change in the

QUIZ ANSWERS