Mechanochemical effects of ultrasound on mung bean starch and its octenyl succinic anhydride modified starch

The purpose of this study was to investigate the mechanochemical effects of ultrasound on the quality of mung bean starch and its octenyl succinic anhydride modified starch (OSAS) in an attempt to produce high quality starch products. In this paper, mung bean starch was treated by ultrasound for 0, 1, 8, 32 and 60 min. Then, under the same ultrasonic treatment conditions, OSAS was prepared by ultrasonic assisted. During the esterification process, the suspensions were also treated for 0, 1, 8, 32 and 60 min, respectively. The results showed that the structures of modified mung bean starch became loose and the crystallinity decreased from 24.2 +/- 0.05(a)% to 21.6 +/- 0.02 (c)% after 1 min of ultrasonic treatment. The Maltese crosses of starch granules became blurred and the gelatinization enthalpy decreased from 11.52 +/- 0.50(a) to 10.47 +/- 0.53 (c). Besides, the reaction efficiency increased from 40.87 +/- 0.04(d) to 48.60 +/- 0.02 (c) and other qualities (solubility, swelling power and viscosity properties) of OSAS were significantly improved. While there were different changes in the structures, properties and qualities of modified starch after ultrasonic treatments for 8 min and 32-60 min. Consequently, these changes showed that ultrasonic treatment had a marked mechanochemical effect on starch granules. So the qualities of OSAS were improved significantly.