Native starches of potato, wheat, maize, and waxy maize were oxidized using sodium chlorate(I), hydrogen peroxide in the presence of Cu2+ ions, and sodium chlorate(III) in the presence of formaldehyde. In order to evaluate the effectiveness of oxidation, the content of carboxyl & aldehyde groups was evaluated in the modified starches. Changes in the susceptibility of native starches and modified starch preparations to retrogradation were determined on the basis of 2% starch pastes prepared and stored at 8°C for 21 days. The turbidity was measured on the 1st, 3rd, 5th, 7th, 10th, 14th, and 21st day of storage. Moreover, the amylose content was measured in those native & modified starches. The results obtained allowed for the statement that the oxidation of potato starch using all the agents as quoted above reduced the retrogradation. Sodium chlorate(I) was the only modifying agent to cause the decrease in the susceptibility of all the starch types to retrogradation. The fact that various starch types differently behaved during the retrogradation process are not connected only with the type of oxidant used, but, first of all, with a different nature and structure of starch granules which depends on its botanic origin.
starch, oxidation, retrogradation