Modification of multi-scale structure, physicochemical properties, and digestibility of rice starch via microwave and cold plasma treatments

The effects of microwave (MW) treatments for 30 and 90 s or cold plasma (CP) treatments for 2, 6, and 10 min on structural, physicochemical, and digestive properties of rice starch were investigated and compared with the effects of combined MW and CP treatments. Dual modification of starch using combined MW and CP treatments significantly changed starch granules' morphology, and starch showed lower crystallinity, swelling power, and peak viscosity than rice starch with a single modification. However, no significant changes were found in rice starch's crystalline structure and FT-IR spectra pattern after single or combined treatments. Effects of these treatments on the amylopectin branch chain length distribution and molecular weight of rice starch varied considerably depending on treatment type and treatment duration. Moreover, the dually modified rice starch contained more great content of resistant starch. Thus, the synergistic effects between MW and CP had more profound modification than the single treatment. Also, the dual treatment can be used to produce modified starch for industrial applications.