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Rheological properties of oxidized starch, modified with sodium hypochlorite (NaOCI), were studied by dynamic viscoelastic measurement during heating and cooling. In rheological properties of oxidized starch suspensions, the storage modulus (G´) and loss modulus (G") of oxidized starch suspensions increased, however tanδ rapidly decreased after gelatinization. Further heating caused a decrease of the moduli. The increase in G´ was due to starch granule swelling and the decrease in G´ as a softening of the granules. Oxidized starch pastes had not only high G´ but also high G", it means that the ability of gel formation was reduced by oxidation. Considerable increase of G´ in untreated starch paste during cooling was probably due to aggregation of amylose. But such transition was reduced with oxidation increasing, which brought to break up amylopectin and increase introduction of carboxyl groups in starch molecules, making three-dimensional network impossible.
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