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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Grain Quality and Structure Research » Research » Publications at this Location » Publication #421631
Research Project: Grain Composition Traits Related to End-Use Quality and Value of Sorghum

Location: Grain Quality and Structure Research

Title: Morphology, composition and structure of starches during sorghum seed development

Author
item LI, DONGXING - Kansas State University
item JIAO, YINPING - Texas Tech University
item Wu, Xiaorong
item Bean, Scott
item SHI, YONG-CHENG - Kansas State University

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2025
Publication Date: 3/12/2025
Citation: Li, D., Jiao, Y., Wu, X., Bean, S.R., Shi, Y. 2025. Morphology, composition and structure of starches during sorghum seed development. Cereal Chemistry. 102:256-265. https://doi.org/10.1002/cche.10875.
DOI: https://doi.org/10.1002/cche.10875

Interpretive Summary: Sorghum is an important crop grown in the central Great Plains of the U.S. The major component of sorghum grain is starch and starch content is an important factor in ethanol production, food quality, and feed properties of sorghum. Even though starch is the major component of sorghum grain, relatively little is known about starch production in the developing grain. This project investigated starch development in sorghum grain from 5 days after flowering through maturity at 25 days after flowering. The primary starch component, amylose (a linear glucose polymer), significantly increases in quantity and undergoes structural changes as the grain develops, while the branched glucose polymer, amylopectin, shows minimal structural variation during this process. This study is one of the first to document the formation of starch in sorghum at very early stages of grain development and will impact future studies on starch development in sorghum and other grains.

Technical Abstract: Starch granule initiation and starch molecule deposition as the granule enlarging are always the fundamental questions in starch chemistry. The property variations of starches in sorghum seeds from 5th to 25th DPA (day post anthesis) was investigated to contribute the basic information for this final answer. The minimal size of sorghum starch for observing Maltese cross was 4 µm. The average size of starch granules at 5 DPA was 3.2 µm, which mostly did not exhibit Maltese cross at this stage. Amylose content in starches increased from 13.0% at 5 DPA to 31% at 25 DPA. The amylose at 5 DPA showed 72.2% long chains, The long chain amylose varied from ~34% to 50% in samples at 10 DPA and 25 DPA. The short chains in amylopectin increased significantly in samples at 25 DPA. The low amylose content and high proportion of long amylose might be favorable for the initial sorghum starch formation. The starch polymers were less radially oriented in the initial stage of starch granule formation. Amylopectin structure in the periphery of large sorghum starch granules branched more than those in the inner part. The variations on the amylose length distributions and orientation of starch polymers would provide new information on starch biosynthesis in sorghum.