Impact of annealing on the physicochemical properties of unfermented cassava starch ("polvilho doce")

Unfermented cassava starch ("polvilho doce") was subject to annealing treatment at 50degreesC for 24, 48, 96, 120, 168 and 192 h, in 1:5 starch to water ratio. The annealing treatment changed the internal structure of "polvilho doce" at increasing treatment time. Peak viscosities decreased significantly, denoting that there was a decrease in leaching of amylose from the granules. The pasting temperatures were increased, setback and breakdown were reduced while hold and final viscosities increased, showing an improvement of the stability of the paste. Swelling power and solubility were reduced at all temperatures and the solubility at 55degreesC was zero after 120 h of treatment. The DSC data for T-o, T-p, T-c and DeltaH increased and the gelatinization range was narrowed. The X-ray diffractograms changed from C-A to A pattern (samples annealed for 48, 96, 120, 168 and 192 h), denoting an increase in organization of double helices of amylopectin. Annealing imparts to the samples some waxy starches characteristics which can be very useful in the food industry.