STARCH RELATED CHANGES IN STORED SOFT SORGHUM PORRIDGE

Soft sorghum (Sorghum bicolor (L.) Moench) unfermented porridge was prepared by cooking pearled sorghum flour (6% solids in water) in a microwave oven. Fermented porridge was prepared by mixing with Lactobacillus delbruekii for 12 hr at 48 degrees C, followed by cooking. Porridge was aged (0-12 hr) at 25 degrees C or 7.5 degrees C. Starch polymer solubility was determined by high performance size exclusion chromatography (HPSEC) and theology followed with a rotational viscometer. During aging, solubilized and gelled amylose and amylopectin retrogradation rates were higher in porridge stored at 7.5 than at 25 degrees C. Amylose polymer solubility decreased with storage, while solubilized amylopectin remained in solution. Fermented porridges were lighter in color and their initial consistency indexes increased faster. HPSEC of soluble polymers was more sensitive than enzymatic starch digestion.