Cold plasma induced degradation of κ-carrageenan: Characterization of degradation product and its application as a...

The present study aims to structurally and rheologically characterize the cold plasma-induced degradation product of κ-carrageenan and explore its application as a thaw stabilizer in plant-based patties. κ-CG was exposed to cold plasma of input voltage 170, 200, and 230 V for 10, 20, and 30 min, followed by characterization. Intrinsic viscosity reduced by ∼40 % at the extreme treatment condition of 230-30 which demonstrates depolymerization following a zeroth order kinetics. The depolymerized κ-CG was found with lower viscosity (∼639.51 Pa·s), elastic (G'-53.41 Pa), and viscous (G″-23.66 Pa) modulus compared to that of untreated one (1053.70 Pa·s; 171.26 Pa; 88.60 Pa respectively). The structural degradation affected the thermal stability of κ-CG indicated by a drop in melting point (from ∼54.21 °C to ∼41.11 °C). The ¹H NMR and FT-IR revealed that the sulfate esters at the C-4 position of galactose-4-sulfate are substituted with hydroxyl groups thus desulfating the polysaccharide. These phenomena synergistically prevent aggregation of κ-CG to reduce syneresis of water from the κ-CG gels by almost ∼83.33 %. Cold plasma degraded κ-CG increased the thaw stability of plant patties with reduced hardness due to better water uptake capacity. This proves cold plasma is a prospective green modification technology for commercial polysaccharides.