Assessing the impact of plasma-activated water-assisted heat-moisture treatment on the extrusion-recrystallization process of hausa potato starch

Abstract

The study explored the plasma-activated water (PAW)-assisted heat-moisture treatment (HMT) on the structural, physico-chemical properties, and in vitro digestibility of extrusion-recrystallized starch. Native starch of hausa potatoes underwent modification through a dual process involving PAW-assisted HMT (PHMT) followed by extrusion-recrystallization (PERH) using a twin-screw extruder. The PHMT sample showed surface roughness and etching with a significantly greater (p ≤ 0.05) RC (20.12 %) and ΔH (5.86 J/g) compared to DHMT. In contrast, PERH-induced structural damage, resulting in an irregular block structure, and altered the crystalline pattern from A to B + V-type characterized by peaks at 17.04°, 19.74°, 22°, and 23.94°. DSC analysis showed two endothermic peaks in all the extrusion-recrystallized samples, having the initial peak attributed to the melting of structured amylopectin chains and the second one linked to the melting of complexes formed during retrogradation. Dual-modified samples displayed notably increased transition temperatures (To₁ 74.54 and 74.17 °C, To₂ 122.65 and 121.49 °C), along with increased RS content (43.76 %-45.30 %). This study envisages a novel approach for RS preparation and broadens the utilization of PAW in starch modification synergistically with environmentally friendly techniques.

Keywords: Extrusion-recrystallized starch; Heat-moisture treatment; In vitro digestibility; Plasma-activated water.