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United States Department of Agriculture

Agricultural Research Service

Title: Digital Image Analysis of Isolated Starch from Wheats of Different Classes and Application of Correction Factors to Determine Starch Size Distributions

Authors
item Bechtel, Donald
item Wilson, Jeff

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2001
Publication Date: October 14, 2001
Citation: Bechtel, D.B., Wilson, J.D. 2001. Digital image analysis of isolated starch from wheats of different classes and application of correction factors to determine starch size distributions. Meeting Abstract.

Interpretive Summary: Presented at the 2001 American Association of Cereal Chemists Annual Meeting held in Charlotte, NC, from October 14-18, 2001.

Technical Abstract: Starch is most abundant storage reserve in the wheat caryopsis yet little is known about its influence on end use properties. Starch was isolated from wheat grains of different classes and analyzed using digital image analysis coupled to a light microscope to determine starch size distributions. The image analysis data was converted into volume data. Starch granules with diameters greater than 5 um were treated as oblate spheroids for calculating volume using the formula for an oblate spheroid. The measured equivalent diameter and an estimated starch granule thickness value were used for the major and minor axes in the oblate spheroid formula, respectively. Granules less than 5 um in diameter were treated as spheres. Starch granules that had their perimeter touching the edge of field of view had their volumes corrected using correction formulae. Correction formulae were developed for each wheat class or starch size distribution class. Correction formulae were important because without them up to 50% of the large Type A granules could be under counted. Data indicated that there can be a wide variation in the size distribution of starch depending on wheat class and environmental effects. Some wheats exhibited a trimodal distribution of starch while others only exhibited a bimodal distribution. This data will be used to help predict wheat quality.

Last Modified: 10/1/2014
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