Cereal Chem 72:80-84  |  VIEW ARTICLE

Starch Solubilization and Retrogradation During Preparation of To (a Food Gel) from Different Sorghum Cultivars.

A. B. Bello, R. D. Waniska, M. H. Gomez, and L. W. Rooney. Copyright 1995 by the American Association of Cereal Chemists, Inc. 

Starch solubilization and retrogradation were studied during the preparation of a food gel called to. To was prepared from flours of four sorghum cultivars with different endosperm textures. Flour and water slurry (17% solids) at pH 8.6 was cooked for 5 min to yield a hot paste (fresh to) or allowed to cool for 1 hr at 25 C to yield a stiff gel, (aged to). Fresh and aged to were dispersed in water at 25 C by blending and centrifuging. Soluble starch was extracted at 35 C, and the apparent molecular weight was quantified by high- performance, size-exclusion chromatography. Amylose (AMY) and amylopectin (AMP) starch was only partially solubilized in fresh to. Aged to contained even less soluble starch. Although more soluble starch was observed in fresh to prepared from sorghums with more corneous (hard) endosperm than floury (soft) endosperm, the resulting aged to contained significantly less soluble starch. Increased firmness of aged to prepared from the more corneous sorghums corresponded to more starch retrogradation as measured by loss of soluble starch. Higher molecular weight soluble AMY and AMP were observed in fresh to compared to aged to. Retrogradation of soluble AMY and AMP in fresh to appears to be faster for higher molecular weight than for lower molecular weight polymers.