Original Paper

Journal of Food Measurement and Characterization

, Volume 7, Issue 4, pp 149-157

First online:

A multispectral sorting device for isolating single wheat kernels with high protein content

  • Ron P. HaffAffiliated withUSDA-ARS-WRRC Email author 
  • , Tom C. PearsonAffiliated withUSDA-ARS-CGAHR
  • , Elizabeth MaghirangAffiliated withUSDA-ARS-CGAHR

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Automated sorting of single wheat kernels according to protein content was demonstrated using two novel multispectral sorting devices with different spectral ranges: 470–1,070 nm (silicone based detector) and 910–1,550 nm (InGaAs based detector). The multispectral data were acquired by rapidly (~12 kHz) and sequentially pulsing LEDs at nine wavelengths and measuring the amount of light reflected from the wheat kernels at each wavelength as they drop off a feeder chute. A microcontroller was used to direct the LED pulses, digitize the analog signal from the photodiode, perform signal processing, and apply classifications. Sorting was accomplished through activation of an air valve. The instruments were tested by sorting 13 hard red winter samples to select high protein kernels. The resulting sample of high protein kernels was sorted a second and third time to further increase average sample protein content. For the silicone based instrument, the sorted samples had 0.99, 1.60, and 1.86 % higher protein than the original samples after each sort, respectively. Similarly, after sorting with the InGaAs based LED instrument, sorted samples had 0.60, 1.25, and 1.68 % higher protein than the original samples after one, two, and three sorts, respectively. The simple LED-based sorter is very economical as compared to most other small scale sorting systems, with material costs for the prototype of around $6,000. This sorter would likely be most effectively employed to select desired traits of small lots of seed (e.g., breeder size samples), assist in sample purification, and help breeders in selecting the kernels with higher protein.


Light emitting diodes Sorting Wheat Protein content