Abstract: The preparation and properties of degraded corn starch were studied by using corn starch as a raw material, ammonium persulfate as oxidant, sodium hydrogen sulfite as reducing agent and hydrochloric acid as an acidulate agent. The effects of reaction time, reaction temperature and reagent dosages on the rheological behavior of degraded corn starch were investigated. The degradation of corn starch was carried out in three different ways, and starch with lower viscosity could be obtained in a shorter time, which retained starch particle and had good rheological property. When hydrochloric acid and ammonium persulfate were used as the degrading agent, acid hydrolysis and oxidation were simultaneously performed during the reaction, which can shorten the reaction time and improve the reaction efficiency. When the ammonium persulfate sodium bisulfite redox system was used to degrade the starch, the initiation rate was fast at a low temperature with sufficient reaction and high efficiency. The effect of using ammonium persulfate only to degrade starch is relatively poor.

Key words: corn starch; acid hydrolysis; oxidation; reduction; rheological behavior