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NIR Technology Australia
Application Note 02: Cropscan 2000G Sorghum Analysis
February 2000
Introduction
The Cropscan 2000G Whole Grain Analyser has been used to develop a
calibration capable of predicting both the protein and moisture content of
sorghum samples grown in Australia. Near Infrared (NIR) spectra of sorghum are
shown below.
.
Description
52 samples of sorghum were scanned on the Cropscan 2000G between
720-1100nm using a 16mm pathlength cell. Using the software package
Unscrambler, a partial least squares (PLS-1) regression was performed on the
data to develop a calibration, which relates the spectral data to the
prescribed protein and moisture values of the sorghum samples
Results
Ten (10) duplicate sorghum samples were used as a prediction set to determine
the predictive ability of the calibration model produced. The individual
samples were scanned five (5) times and the average was taken as the protein
and moisture values. The results are shown below
|
Sample ID |
Protein NIR (1) |
Protein Ref (2) |
Diff (1) & (2) |
Moisture NIR (3) |
Moisture Ref (4) |
Diff (3) & (4) |
|
1a |
10.2 |
10.1 |
-0.1 |
11.4 |
11.9 |
0.5 |
|
1b |
10.2 |
10.1 |
-0.1 |
11.3 |
11.9 |
0.6 |
|
2a |
10.3 |
10.3 |
0 |
12.9 |
13.2 |
0.3 |
|
2b |
10.3 |
10.3 |
0 |
12.9 |
13.2 |
0.3 |
|
3a |
7.9 |
7.7 |
-0.2 |
12.9 |
12.8 |
-0.1 |
|
3b |
8.2 |
7.7 |
-0.5 |
12.8 |
12.8 |
0 |
|
4a |
9.7 |
9.3 |
-0.4 |
13 |
13.2 |
0.2 |
|
4b |
10.1 |
9.3 |
-0.8 |
13 |
13.2 |
0.2 |
|
5a |
9 |
9.5 |
0.5 |
11.9 |
11.8 |
-0.1 |
|
5b |
9 |
9.5 |
0.5 |
11.9 |
11.8 |
-0.1 |
|
6a |
9.3 |
9.5 |
0.2 |
12 |
12.2 |
0.2 |
|
6b |
9.3 |
9.5 |
0.2 |
12.1 |
12.2 |
0.1 |
|
7a |
8.6 |
8.4 |
-0.2 |
12.1 |
12.1 |
0 |
|
7b |
8.6 |
8.4 |
-0.2 |
12.1 |
12.1 |
0 |
|
8a |
9.7 |
10.3 |
0.6 |
11.8 |
11.9 |
0.1 |
|
8b |
9.9 |
10.3 |
0.4 |
11.8 |
11.9 |
0.1 |
|
9a |
9.2 |
10.1 |
0.9 |
13.4 |
13.4 |
0 |
|
9b |
9.3 |
10.1 |
0.8 |
13.5 |
13.4 |
-0.1 |
|
10a |
8 |
7.5 |
-0.5 |
12.4 |
11.8 |
-0.6 |
|
10b |
8 |
7.5 |
-0.5 |
12.5 |
11.8 |
-0.7 |
Statistical analyses of the above data are given in the following table
|
|
Protein Analysis |
Moisture Analysis |
|
Bias |
0.03 |
0.04 |
|
Standard Deviation |
0.47 |
0.31 |
|
SDD* |
0.15 |
0.07 |
* SDD = Standard Deviation of Differences between duplicate samples
A graphical representation of the data is presented below
Conclusion
The Cropscan 2000G can be used to measure the moisture content in
sorghum with a good reproducibility (SDD for the duplicate samples of 0.07%)
and acceptable accuracy. This provides a method for farmers to confidently
deliver sorghum with a moisture content less than 13.5% (which is the maximum
allowable level). Also the farmer is potentially able to deliver a more
marketable product on the basis of higher protein content (which is can be
measured to an accuracy of 0.5%).