Effect of Plasma-Activated Water and Direct Cold Plasma Treatment on Functional and Rheological Properties of Little and Kodo Millet Flours

Abstract

Minor millets such as little and kodo millets have a good source of nutrition health advantages. Considering the advantages of these millets, the study was performed to improve the functional and rheological characteristics of millet flour using cold plasma (CP) technology. Multi-pin CP and plasma-activated water at different output voltages such as 10 kV and 15 kV were applied for 30 min. Functional properties such as water absorption capacity (WAC), solubility index (SI), swelling capacity (SC), emulsification ability, and stability for little and kodo millet flours for two plasma systems were studied. All the properties of these flours after treatments were enhanced. SI and SC reached their peak in little millet flour treated with direct plasma at 15 kV for 30 min, measuring 0.061 ± 0.005 g/g and 3.84 ± 0.3 g/g, respectively. Meanwhile, for kodo millet flour, the SI peaked at 0.048 ± 0 g/g with direct plasma at 15 kV for 30 min, and the SC reached its highest point at 2.01 ± 0.53 g/g with plasma-activated water (PAW) treatment at 10 kV for 30 min compared to the control. Additionally, the viscosity of both little and kodo millet flours was highest at 43.63 ± 3.83 and 186.6 ± 6.07 cP, respectively, in PAW-treated samples at 15 kV for 30 min. Rheological parameters were also measured. An increase in storage and loss modulus was noticed with a rise in frequency. Crystallinity diminished in both millet flours following direct and PAW treatments. Overall, comparing both plasma systems for little and kodo millet flours, both systems improved the functionality and rheological parameters.