A novel modification of guinea grass seed starch by multipin atmospheric cold plasma: Structural, functional, and rheological characterization.

The present study modifies the guinea grass seed starch (GS) using a multipin cold plasma system at different voltages (20 and 30 kV) and treatment times (5, 10, and 15 min). The structural, morphological, functional, rheological, and textural characteristics of native and plasma-treated GS were determined to study the impact of voltage and duration. The amylose content decreased (27.72 % in native to 26.75 % in 30 kV-15 min) as voltage and treatment time increased. Micrograms revealed that the surface of starch granules became more rough, asymmetrical and aggregated and higher voltage and time resulted in aggregate formation, which increased the smaller fractions. However, FTIR and XRD analyses revealed minor structural changes with decreased crystallinity (27.60 % to 21.67 %). Cold plasma treatment increases the zeta potential, swelling power, solubility, water absorption capacity, and oil absorption capacity indicating better water-starch and water-oil interactions, respectively. Pasting analysis showed lower pasting temperature and higher peak viscosity. All starch gels showed shear-thinning behavior, with the storage modulus (G') consistently exceeding the loss modulus (G″), indicating that the gels were predominantly elastic. Syneresis analysis showed increased water outflow, indicating decreased freeze-thaw stability. Conclusively, the physicochemical and functional enhancements of GS through cold plasma treatment could establish it as a functional ingredient for food.