| Abstract: | Normal maize, waxy maize and amylomaize V starches were treated at a moisture content of 70% by ultrasonic treatment. The results showed that the surface of normal and waxy maize starches was porous after treatment and a fissure could be clearly observed in the surface of amylomaize V starch. Ultrasonic treatment did not change the X‐ray pattern of the three maize starches. The swelling power (amylomaize V (B‐type) > normal maize > waxy maize (A‐type)) and solubility (amylomaize V > normal maize > waxy maize), the syneresis of amylomaize V starch and the gelatinization transition temperatures of the three starches increased on this treatment. Ultrasonic treatment decreased the syneresis of normal and waxy maize starches, the enthalpy of gelatinization (amylomaize V > waxy maize ≈︂ normal maize) and the gelatinization temperature range (amylomaize V > normal maize ≈︂ waxy maize) of all starches. A drop in viscosity of all three starches was observed and the viscosity patterns of three starches remained unchanged after ultrasonic treatment. The data showed that ultrasonic treatment degraded preferentially the amorphous regions and more easily attacked linear amylose than highly branched amylopectin. |
