Effect of ultrasound pretreatment on enzymolysis and physicochemical properties of corn starch.

In the paper, the effects of ultrasound on the enzymolysis properties of corn starch were investigated. The results showed that the rate of enzymolysis changed with the change of ultrasonic conditions. Ultrasound pretreatment starches reduced the time in liquefaction process, and resulted in significantly higher DE value in saccharification process. DE value was negatively correlated to PV, BV, SV, To, Tp, ΔHg, DO, DD, N-O'KI, RC, Mw and DP, respectively, and positively correlated to Mw/Mn. X-ray diffraction analysis showed that the relative crystallinity was reduced, and the starch exhibited an A-pattern. Scanning electron microscope indicated that the notch and groove appeared on the surfaces of starch granules. The polarized cross of starch becomes smaller or even disappear. It was concluded that enzymolysis efficiency of different ultrasound pretreatment to changes due to its effect not only on the physicochemical properties, but also on the structural characteristics of corn starch.