Effect of ultrasonic treatment on the physicochemical properties of maize starches differing in amylose content.

摘要

Normal maize (corn), 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 3 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 temp. of the 3 starches increased after 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 temp. range (amylomaize V > normal maize waxy maize) of all starches. A drop in viscosity of all 3 starches was observed and the viscosity patterns of the 3 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.