Classifying macadamia kernels with near-infrared (NIR) analysis using the Luminar 5030 by Brimrose. In this presentation I show an example of classification and discuss the potential of applying NIR to grade and sort macadamia.

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Classification of macadamia kernels by
NIR analysis: preliminary analysis
Daniel Pelliccia
Instruments & Data Tools

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Instruments & Data Tools: capabilities
3D IMAGING3D ANALYSISNIR ANALYSIS

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Outline
1. The instrument: Brimrose Luminar 5030
2. Samples: macadamia kernels
3. Results and discussion: Principal Component Analysis
4. Discussion & Conclusion

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The instrument: Brimrose AOTF analyser Luminar 5030
The Luminar 5030 spectrometer is based on an
Acousto-Optic Tunable Filter (AOTF).
NIR region 1100 nm - 2300 nm
Resolution 2 nm
Gain 1x
Scans Per Average 100
Acquisition mode Reflectance
Acquisition parameters

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Samples: macadamia kernels
Samples of macadamia kernels were kindly provided by Kim Jones of Cropwatch Independent
Laboratories.
Sample type and ID Number of kernels (or part thereof)
Fresh, CV 344 10
Fresh, CV A16 6
Stale, FREC 936-16 7
Rancid, No2 2L-BOL 7
All samples had an associated hexanal reading, which will be used in a future regression work. This
analysis is restricted to kernel classification using Principal Component Analysis (PCA).

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Results: representative spectra and second derivative
Spectra Second derivative
- The spectra are the average of the 10 measurements taken on each kernel
- Noticeable difference between fresh and other kernels

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Results: PCA in 1200-1400 nm band
● Fresh kernels (green and blue dots) are well
separated from the rest.
● Stale and rancid kernels are partially
overlapping.
● Preliminary evidence that the fresh kernels
from the two different cultivars could also be
separated, based on their PC2 value.
NIR analysis may be capable of segregating
kernels according to their source.
Analysis on a larger number of samples is
required to check validity.

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Results: PCA in 1850-2050 nm band
● Stale and rancid kernels are well separated
● Fresh kernels tend to overlap more: mixing
between cultivars
● This is suggesting a two-step approach to
classifying macadamia kernels
This is suggesting a two-step approach to
classifying macadamia kernels
Again, a larger number of samples is required to
check validity.

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Conclusion
● The classification of macadamia kernels according to their status can be accomplished by NIR
analysis using a Brimrose Luminar 5030 handheld analyser.
● The results of this preliminary analysis suggest that NIR analysis is able to segregate kernels of
different oxidation stage, fresh, stale and rancid with good accuracy.
● Results also suggest that NIR may be able to segregate kernels based on their source cultivar.
● Further analysis, on a larger number of samples, is however required to draw more general
conclusions and provide recommendations.
Instruments & Data Tools Pty Ltd
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