Quality, composition, and starch properties of sorghum to, a thick porridge

To is thick porridge prepared by cooking a flour slurry in boiling water with continuous stirring. The relationship between to texture and solubility properties with physicochemical characteristics of sorghum with different to qualities was investigated. Starch was isolated and used for fundamental studies on factors affecting to quality. Aqueous high performance size exclusion chromatography was used to study molecular properties of starch. Starch retrogradation was measured indirectly by the difference in the amount of soluble solids (SS), soluble amylose and soluble starch before and after cooling of to prepared from flour or starch.; Starch and other flour components were solubilized during to preparation. Softer to texture was significantly correlated with SS. More SS was observed in alkaline to compared to acidic and neutral to; the alkaline to was softer in texture. The SS from alkaline to contained mainly starch ({dollar}ge{dollar}90%) and low levels of protein ({dollar}<{dollar}5.0%), ash ({dollar}<{dollar}2.0%) and fat ({dollar}<{dollar}0.5%).; More starch was initially solubilized in to prepared from flour or starch from sorghums with corneous endosperm than those prepared from floury endosperm sorghum. However, more starch retrogradation occurred in to prepared from corneous endosperm sorghum resulting in to with a firmer texture and less soluble starch. In a model experiment, to prepared from flour containing 0.5% SSL was softer in texture because less amylose was solubilized and the solubilized amylose complexed with SSL, preventing it from retrograding.; Corneous endosperm starch contained higher MW amylose and lower MW amylopectin than floury endosperm starch. The apparent MW average of amylose was 4.0 to 6.0 {dollar}times{dollar} 10{dollar}sp5{dollar} in starch from corneous endosperm sorghum and 2.0 to 3.0 {dollar}times{dollar} 10{dollar}sp5{dollar} in starch from floury endosperm sorghum. The higher MW amylose (4.0 to 6.0 {dollar}times{dollar} 10{dollar}sp5{dollar}) and intermediate MW amylopectin (2.5 to 6.0 {dollar}times{dollar} 10{dollar}sp6{dollar}) that were solubilized during cooking became insoluble during cooling.; Softer to texture was significantly correlated with flour protein, ash, fat and pentosan contents. Whole-flour and the fine-flour ({dollar}<{dollar}250 {dollar}mu{dollar}m) fractionated from ground decorticated sorghum contained more pericarp and germ tissues which contained high levels of protein, ash, fat and pentosan. Hence, to prepared from those flours was softer in texture.