The Influence of Thickness in Plasma-Induced Modifications of Finger Millet Starch (Eleusine coracana): Insights for Industrial Scalability

The study explored the effects of different thicknesses of finger millet starch (FMS) treated with cold plasma to determine the critical thickness required to observe significant plasma-induced changes. Thin (TN), intermediate (IM), and thick (TK) FMS samples with average starch bed thickness of 0.3, 0.6, and 0.9 mm were exposed to plasma, revealing notable changes in physicochemical, functional, thermal, and rheological properties. Polymer breakdown rate as obtained by zero-order was 1.16 × 10⁻¹. Thickness variation significantly influenced starch modification, with TK displaying reduced plasma effects. TN had lowest molecular weight of 1.96 × 10⁷ g/mol in comparison to untreated sample (5.30 × 10⁷ g/mol); thus, TN sample was farthest to untreated sample on the principal component analysis (PCA) biplot. PCA identified key properties; furthermore, modelling with linear or power law was conducted to find out the critical thickness. This research, thus, provides concrete data helpful in devising the plasma system for facilitating future industrial-scale starch modification.