The multi-scale structure and physicochemical properties of mung bean starch modified by ultrasound combined with plasma treatment

Plasma is a simple, effective and promising food processing technology with great potential for starch modification. Mung bean starch was subjected to ultrasound (300 W, 10, 30 and 50 min), plasma (40 V, 1, 3 and 9 min) and the synergistic treatment, as well as investigating its effects on the morphology, chain length distribution, molecular weight, crystalline structure and physicochemical properties of starch. Ultrasound and plasma treatment did not change the granule shape, but caused some corrosions on the surface, and dual treatment increased the damage degree of starch granules surface. All treatments decreased the molecular weight (Mw), amylopectin long chains and crystallinity but increased the gelatinization temperatures and enthalpy. Different from ultrasound irradiation, single plasma treatment significantly reduced the swelling power and pasting viscosities. Furthermore, dual treatment increased the thermal stability of starch paste, owing to the reinforcement effect between ultrasound and plasma. Thus, dual modification displayed an excellent ability to modify starch with specific characteristics and expand the potential application of mung bean starch in the food industry.