Effects of Sonication on Physical Properties of Native and Cross‐Linked Wheat Starches

Abstract

AbstractThe purpose of this study was to investigate the effects of sonication time and temperature on physical properties of native and cross‐linked wheat starches. Starch aqueous dispersions (30%, w/w) were sonicated with an ultrasonic probe at 20 kHz, 100% wave amplitude and sonication power of 100 W for 5, 10, 15 and 20 min at 5 and 22C. Increase in cold‐water solubility, decrease in intrinsic viscosity, gelatinization enthalpy, peak, trough, setback and final viscosities of both starches were observed by increasing the sonication time and temperature. Ultrasonic treatment resulted in the formation of some fissures and cracks on the exterior of the granules as observed by a scanning electron microscope. In general, the effects of ultrasonic treatment on both starches increased with increment in processing time and temperature. The cross‐linked wheat starch was more resistant against ultrasonic treatment than the native counterpart.Practical ApplicationsPower ultrasound has been known as an emerging technology in many food processing operations including emulsification, freezing, extraction, drying and inactivation of pathogenic bacteria on food contact surfaces. In many foods that may undergo ultrasound processing, starch and its derivatives are widely used. This research provides information on the effects of different conditions of ultrasound on native and cross‐linked wheat starches as two common starches in many food products. It showed that the cross‐linked wheat starch is more stable in ultrasound processed foods compared to its native counterpart.