Effects of dry-heat treatment on amylose content, hydration, structural and pasting properties of Kodo flour for application in breakfast cereal

Kodo millet is of the Poaceae family that thrives well under abiotic stress and scanty rainfall and possesses the goodness of iron and a low glycemic index. Notably, its low amylose content hinders the manufacturing of breakfast cereals due to its meager expansion. A purely chemical-free modification method of dry-heat treatment (DHT) on hulled Kodo flour within restricted moisture (15–20%) and heat prolongation (2–4 h) at 130 °C was evaluated on its physicochemical properties. In our study, the impact of DHT on flour quality, enhanced amylose content (11.44%), paste clarity (38%), bulk density (22.90%), relative crystallinity (20.62%), degree of helix order (32.94%), and granule size (13.01%) relative to untreated flour was investigated. Hydration properties, such as amylose leaching, water activity, water and oil absorption capacities, solubility index, and swelling power, exhibited a significant (p < 0.05) decrease. The crystallinity pattern of all samples exhibited an A-type polymorph. DHT20-4h, which was incorporated with hybrid maize flour (70:30) followed by extrusion, exhibited higher crystallinity (51.94%) and generated more amorphous sites of B-type polymorph, with a reduction in relative crystallinity of 20.66% for extrudate BC-2. Extrudate BC-2 adhered to a large cell volume having 16.55 times enlargement with lower amylose content relative to extrudate BC-1 prepared from untreated flour, containing more than 50% of whole-Kodo ingredients. Thus, breakfast cereals developed using modified Kodo millet flour (DHT20-4h) ensured better texture and expansion, strengthening a shift to climate-resilient millet production and value addition, protecting the environment over time.