Starch modification utilizes a substantial amount of water. This research aimed to investigate the effect of nonthermal dielectric barrier discharge (DBD) argon and helium plasma on tapioca starch's physicochemical properties and techno-functionality. Dry starch samples were treated with plasma generated from argon and helium gases at different voltage levels (10 and 15 kV) for 5, 10, and 15 min. The treatment did not destroy the starch's crystalline structure, as evidenced by the birefringence under polarized light. Scanning electron micrographs showed dented starch granules. A marginal decrease in pH value of all treated samples was noted. A reduction in amylose and amylopectin molecular weight and increased reducing sugars were observed in the treated samples. Fourier transform infrared spectroscopy analysis showed a slight change in the 1047/1022 cm-1 absorbance ratio, indicating a change in short-range ordered degree of starch, while X-ray diffractometry showed a decrease in crystallinity. A significant reduction in peak viscosity, breakdown, and setback was observed. The gelatinized plasma-treated starch dispersion showed less shear-thinning and less thixotropic with increasing voltage and treatment times. This research proved that modification of starch in the solid-state using nonthermal plasma is feasible.
Keywords: Argon; Dielectric barrier discharge; Helium; Nonthermal plasma; Starch modification; Tapioca starch.
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