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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 #267570

Title: The effect of kernel maturity on the thermal properties of sorghum starch

item Kaufman, Rhett
item Wilson, Jeff
item SHI, Y - Kansas State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2011
Publication Date: 10/16/2011
Citation: Kaufman, R.C., Wilson, J.D., Shi, Y.C. 2011. The effect of kernel maturity on the thermal properties of sorghum starch. AACC International Annual Meeting. Meeting Abstract. Cereal Foods World. 56:A47.

Interpretive Summary:

Technical Abstract: Starch is a widely used component in both food and industrial applications. Critical components in the functionality of starch in a food or industrial system are its thermal properties. The objective of this study was to determine if the thermal properties of starch change as sorghum develops. Two sorghum hybrids, a red pericarp/purple plant and a white pericarp/tan plant (food grade) were grown in irrigated plots at Kansas State University in 2008 and 2009; upon reaching the mid-bloom stage in maturity approximately 200 heads were tagged. Samples were regularly collected beginning ten days after anthesis (DAA) until harvest. The samples were then decorticated, the starch isolated and the thermal properties measured using differential scanning calorimetry (DSC). The onset gelatinization temperature means of both hybrids ranged from 61.4°C to 67.0°C. The change in enthalpy ('H) ranged from 7.6 J/g to 15.8 J/g in 49DAA and 14DAA, respectively. Statistical separation was also observed between the two sorghum hybrids for gelatinization temperatures and 'H. The samples were then retrograded for seven days at 4°C. The onset temperature of the retrograded samples ranged from 41.8°C to 45.7°C. Enthalpy change ranged from 2.1 J/g to 4.2 J/g in 49DAA and 14DAA, respectively. These thermal variations suggest structural changes occurring throughout kernel development as well as hybrid differences. The thermal properties of the sorghum starch could allow for utilization of the starch in differing applications. These developmental variations will provide more insight into how sorghum starch is assembled in maturing caryopsis.