Effects controlled ultrasound and partial hydrolysis of micro starch granules from Colocasia esculenta L. Schott: thermal, morphological and structural properties

Some changes in the starch properties are derived from physical or chemical treatments. Thus, 0.1 mol L −1 , 0.5 mol L −1 hydrochloric acid were established and ultrasound (US) applied for 15 and 30 min to modify the native starch. In addition, the double modification was also tested, applying US after the acid modification. The native starch of the taro (with 23.31% amylose content) showed lower tendency to red colour and tended to yellow. Changes were observed after the application of the treatments. Greater thermal stability was displayed for modified starches, mainly due to ultrasound. In addition, the modification resulted in reduction of the temperatures and enthalpy involved in starch gelatinisation. The structure of the starch granules showed an irregular polyhedral shape with a smooth surface, no changes after the modifications, slight variation of the relative crystallinity and A-type diffraction pattern.