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ARS Home » Plains Area » Lincoln, Nebraska » Wheat, Sorghum and Forage Research » Research » Publications at this Location » Publication #214388
Title: Digestibility of Protein and Starch from Sorghum (Sorghum bicolor)is Linked to Biochemical and Structural Features of Grain Endosperm

Author
item WONG, JOSHUA - UC BERKELEY
item LAU, TSANG - UC BERKELEY
item CAI, NICK - UC BERKELEY
item SINGH, JASWINDER - UC BERKELEY
item Pedersen, Jeffrey
item Vensel, William
item Hurkman Ii, William
item Wilson, Jeff
item LEMAUX, PEGGY - UC BERKELEY
item BUCHANAN, BOB - UC BERKELEY

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2008
Publication Date: 7/13/2008
Citation: Wong, J.H., Lau, T., Cai, N., Singh, J., Pedersen, J.F., Vensel, W.H., Hurkman II, W.J., Wilson, J.D., Lemaux, P.G., Buchanan, B.B. 2008. Digestibility of Protein and Starch from Sorghum (Sorghum bicolor)is Linked to Biochemical and Structural Features of Grain Endosperm. Journal of Cereal Science. 49(1):73-82.

Interpretive Summary: Sorghum is a major source of energy and protein for millions of the world’s poorest people. However, the nutritional value of sorghum is diminished because of the relatively low digestibility of its grain protein. To address this problem, we analyzed the properties of two lines of sorghum with a common pedigree that differ in digestibility. Consistent with published results based on an assay used to predict feed digestibility for livestock, the protein and starch of one line (KS48) was more thoroughly digested than the other (KS51). The indigestibility of KS51 relative to KS48 was shown to be due to (1) a greater abundance of disulfide proteins; (ii) presence of amylose starch and the accompanying enzyme for its synthisis; (iii) and the nature of the starch/protein matrix. The current findings suggest that each of these factors should be considered in efforts to enhance the nutritional value of sorghum grain.

Technical Abstract: Although a principal source of energy and protein for millions of the world’s poorest people, the nutritional value of sorghum is diminished because of low digestibility of grain protein. To address this problem, we analyzed the properties of two lines of sorghum with a common pedigree that differ in digestibility. Consistent with published results based on a ruminal fluid assay, the protein and starch of one line (KS48) was more thoroughly digested than the other (KS51) in in vitro assays based on pepsin and alpha-amylase. The indigestibility of KS51 relative to KS48 was shown to be due to (1) a greater abundance of disulfide proteins; (ii) presence of non-waxy starch and the accompanying granule-bound starch synthase; (iii) and the nature of the starch/protein matrix. The current findings suggest that each of these factors should be considered in efforts to enhance the nutritional value of sorghum grain.