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United States Department of Agriculture

Agricultural Research Service

Title: Comparison of Digital Image Analysis Data to a Laser Light Diffraction Instrument for Analysis of Starch Size Distributions

item Bechtel, Donald
item Wilson, Jeff
item Gaines, Charles

Submitted to: Cereal Foods World
Publication Type: Abstract Only
Publication Acceptance Date: July 10, 2000
Publication Date: November 5, 2000
Citation: Bechtel, D.B., Wilson, J.D., Gaines, C.S. 2000. Comparison of digital image analysis data to a laser light diffraction instrument for analysis of starch size distributions. Abstract No. 80 in: 2000 AACC Annual Meeting Program Book. p.200. Meeting Abstract.

Interpretive Summary: To be presented at the 2000 American Association of Cereal Chemists (AACC) Annual Meeting, November 5-9, 2000, in Kansas City, MO.

Technical Abstract: Digital image analysis and laser light diffraction were used to study starch isolated from a variety of wheat classes. A laser light diffraction system provides rapid analysis of large numbers of particles, but is volume-based with results expressed in terms of equivalent spheres. Since larger starch granules in wheat endosperm are oblate spheroids, light diffraction systems introduce errors in size distribution calculations. Size distributions obtained from image analysis can not be directly compared to those of the laser light instrument because image analysis data is number-based while diffraction data is volume-based. Conversion of the number-based image analysis data to a volume-base resulted in similar size distributions as those obtained from diffraction studies. Fewer large type A granules were present in the image analysis data than from diffraction because of perimeter touching edge of field of view effects, but both had similar mean diameters. The B type granules showed the largest differences where many more granules were counted by image analysis than by the diffraction system. Results indicate that laser light diffraction can be used for routine starch size distribution determinations after calibration using image analysis data.

Last Modified: 4/22/2015
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