Skip to main content
ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Grain Quality and Structure Research » Research » Publications at this Location » Publication #331963

Research Project: Impact of the Environment on Sorghum Grain Composition and Quality Traits

Location: Grain Quality and Structure Research

Title: Sorghum starch properties as affected by growing season, hybrid, and kernel maturity

item KAUFMAN, R - Bayer Cropscience
item Wilson, Jeff
item Bean, Scott
item XU, F - Kansas State University
item SHI, Y - Kansas State University

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2017
Publication Date: 3/1/2017
Citation: Kaufman, R.C., Wilson, J.D., Bean, S.R., Xu, F., Shi, Y.C. 2017. Sorghum starch properties as affected by growing season, hybrid, and kernel maturity. Journal of Cereal Science. 74:127-135.

Interpretive Summary: Sorghum is fifth in worldwide cereal grain production; behind maize, rice, wheat, and barley. In the United States, however, sorghum production ranks third behind only maize and wheat. Sorghum is used in many different applications, such as animal feed, biofuel feedstock, and increasingly in food systems. The objective of this study was to 1) investigate the development of the sorghum starch granule during kernel development 2) investigate the effect of maturity on the starch chemistry and thermal properties. The hybrid type as well as the growing season contributed to differences in the sorghum starch chemistry and functionality as was expected. Starch granule size distribution had considerable variability throughout kernel development. The chemical properties of the starch changed as a result of the maturity level, while others remained constant throughout development. The thermal properties of the starch were also greatly influenced by the maturity. The varying thermal properties could impact the utilization of the starch if the grain was harvested prior to physiological maturity. Further investigation into starch functionality is needed to examine where early levels of maturity could be utilized in food, feed and biofuel feedstock.

Technical Abstract: Starch is a widely used component in the food, feed, and biofuel industries. Critical components in the functionality of a starch in a food or industrial system are the thermal properties. The objective of this study was to evaluate the physical and chemical changes that occur in sorghum starch during grain maturity. Two sorghum hybrids were grown in irrigated plots in 2008 and 2009; upon reaching the mid-bloom stage in maturity approximately 200 heads were tagged in each plot. Samples were collected beginning ten days after anthesis (DAA) until harvest. The samples were then decorticated and the starch isolated. The starch granule size distribution was greatly affected by the collection date as well as the growing season and hybrid. The samples ranged from 16.3% amylose in 10 DAA to 23.3% amylose in 35 DAA. The crystallinity of the starch decreased as the DAA approached physiological maturity (35 DAA). Starch thermal properties were also altered due to DAA, most notably the 'H was 16.1 J/g at 14 DAA, 11.95 J/g at 35 DAA, and 9.45 J/g at 56 DAA. The unique chemical and thermal properties of the starches could allow for utilization of the starch in differing applications.