Title: Rapid Isolation of Sorghum Starch Using Sonication Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 27, 2005
Publication Date: February 19, 2005
Citation: Park, S., Singh, H., Wilson, J.D., Bean, S. 2005. Rapid isolation of sorghum starch using sonication. Proceedings of the 24th Biennial Grain Sorghum Research & Utilization Conference. Meeting Abstract. p. 35. Technical Abstract: The study of cereal starches often requires the isolation of starch from the endosperm. Cereal starches have been isolated by hand-washing, wet-milling, or enzymatic methods. However, these procedures are often tedious and time-consuming. Therefore, the goals of this study were to develop new, rapid and reproducible starch isolation methods using sonication. Decorticated sorghum flour was sonicated in a pH 10.0 buffer with 2% SDS and 2% reducing agent at a solvent to sample ratio of 20:1, followed by water-washing. Sonication times (2, 4, 6, 8, and 10 min) and different reducing agents ('-ME, DTT, and sodium meta-bisulfate) were tested. Protein content of starch was only 0.35-0.45% (db) after a 2-min sonication (using any reducing agent) and was reduced further to 0.15-0.30% (db) using longer times. The sonicated starch was comparable to starch obtained by an enzymatic method (EM) which takes several hours to complete. Starch yield (db) and protein content (db) were 64 and 0.84% for the EM starch, and 69 and 0.42% for the sonicated starch. The color of starch obtained by sonication showed a similar L (brightness) value, (93.9 vs. 93.8) and lower b (yellow) value (2.99 vs. 3.80) than the EM starch. Physiochemical properties of starches from different types of sorghum (hard vs. soft, normal vs. waxy) and the purification of starch from other cereals will be presented. Cereal starches can rapidly be isolated using this procedure.