Impact of Annealing on the Physicochemical Properties of Unfermented Cassava Starch ('Polvilho Doce')

摘要

Unfermented cassava starch ("polvilho doce") was subject to annealing treatment at 50°C 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, showingan improvement of the stability of the paste. Swelling power and solubility were reduced at all temperatures and the solubility at 55°C was zero after 120 h of treatment. The DSC data for T_o, T_p, T_c and AH increased and the gelatinization range wasnarrowed. 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 characteristicswhich can be very useful in the food industry.