Influence of ultrasonication power and treatment duration on the functional and structural properties of elephant foot yam starch

Elephant foot yam (Amorphophallus paeoniifolius) starch is an underutilized C-type tuber starch, whose native properties may limit its functionality in processed food systems. Ultrasonication is a sustainable, reagent-free technique for modifying starch structure and improving its performance. This study investigated the effects of probe ultrasonication power levels (20% and 30% amplitude) and treatment duration (20 and 30 min) on the structural, physicochemical, thermal, textural, and micrometric properties of elephant foot yam starch (EFYS). Ultrasonication significantly increased the apparent amylose content (24.68-26.68%), indicating partial amylopectin depolymerization. Swelling power (13.61-15.92 g/g) and solubility (0.33-0.49%) increased, whereas water absorption capacity decreased (1.13-0.75 g/g). Enhanced solubilization improved paste clarity, and light transmittance. FE-SEM analysis revealed surface erosion and fissures without thermal gelatinization. XRD confirmed the retention of the C-type crystalline pattern with reduced crystallinity, while FTIR indicated disruption of hydrogen bonding and short-range molecular order without chemical alteration. Thermal analysis showed a reduction in gelatinization onset temperature (62.44-50.40°C), and an increase in enthalpy (15.15-17.66 J/g), suggesting molecular rearrangement. Gel hardness and gumminess increased, while powder flowability slightly declined. Overall, controlled ultrasonication efficiently tailored the EFYS properties, indicating its potential applicability in thickening systems and gel-based food formulations.