Combined effect ozonation and ultrasonication on rheological and thermal properties of rice starch in aqueous phase

A combination of ozonation and ultrasonication was applied to rice starch in aqueous phase. A Bohlin rheometer was used to obtain flow behaviour and consistency indices. A differential scanning calorimeter was used to measure the gelatinisation properties (onset, peak and conclusion gelatinisation temperatures and enthalpy of gelatinisation). It was observed that all starch samples exhibited non-Newtonian behaviour (i.e. n<1). The highest viscosity values (i.e. 0.5 Pa.s) and the highest shear-thinning effect (i.e. n=0.4) were observed for ultrasonicated starch sample. The consistency index for native rice starch increased after ultrasonication. There were no significant differences (P<0.05) between the consistency index and apparent viscosity of samples treated with ozonation and ultrasonication with no regards of treating sequence. This showed that the order of treatment (i.e. ozonation and ultrasonication) does not have any significant effect on the flow properties of rice starch studied under the condi...