Non-Equilibrium Cold Plasma as a Sustainable Approach to Improve Functional and Thermal Properties of Pearl and Sorghum Millet Flours

Abstract

This study investigates the effects of non-equilibrium cold plasma (NECP) treatment using air plasma and transient exposure methods on the functional, structural, and thermal properties of pearl and sorghum millet flours. Pearl and sorghum millet flour were treated at two different exposure times for 5 min and 10 min, and functional properties such as Water and oil holding capacity, water binding capacity, color, and dispersibility of the control and plasma-treated flour were studied. There was no significant difference in the color intensity and the whitening index (WI) with the treatment. However, the 10-minute treatment resulted in an increase in water absorption capacity (1.55-1.81 g/g), oil absorption capacity (1.21-1.4 g/g), and water binding capacity (2.25-2.37 g/g) in pearl millet flour. Similarly, sorghum millet flour water absorption capacity (1.43 to 1.74 g/g), oil absorption capacity (1.08 to 1.27 g/g), and water binding capacity (2.07-2.26 g/g) increase with 10 min NECP treatment. In addition, Fourier transform infrared spectrometry analysis detected shifts in functional groups, X-ray diffraction analysis indicated changes in crystallinity, and Differential crystallography showed a reduction in gelatinization enthalpy. Overall, plasma treatment can be explored for the development of a process to enhance the functionality of millet flour for applications in food systems.