EFFECT OF LONGER HEATING TIME ON DEPOLYMERIZATION OF LOW MOISTURIZED STARCHES

Low moisturized potato, sweet potato, corn and wheat starches were tre ated with a flow tester under heated and heated-sheared conditions. Th e starches depolymerized into lower molecule by longer heating time at 150 degrees C. With an increase in heating time, the cold water solub ility of starches increased and the degree of depolymerization progres sed. Comparing heated treatment with longer heating time and heated-sh eared treatment, 60-120min healing was necessary for heated specimens to obtain similar cold water solubility and degree of depolymerization of heated-sheared specimens. These results conducted that heated-shea red treatment strongly promoted the depolymerization of low moist star ches under high temperature as compared with heated treatment only. Fr om the results of lambda(max) of iodine-polysaccharide complex, there was almost same molecular state between heated for longer time and hea ted-sheared treatment. Both amylose and amylopectin depolymerized into lower molecule by both treatments.