Coupling electrostatic and static magnetic fields during drying on the structural and functional properties of starch in fresh-cut purple yam.

The objective of the present investigation was to evaluate the structural, functional, and hydration properties of starch isolated from purple yam slices modified by electrostatic field (EF), static magnetic field (SMF), and combined EF-SMF assisted drying. The results showed that EF-SMF significantly increased amylose content to 178.62 mg/g and reduced relative crystallinity to 31.1 %. Water binding capacity increased markedly to 9.93 g/g, with a corresponding improvement in oil binding capacity. Pasting properties analysis revealed a substantial decrease in peak viscosity along with reduced breakdown and setback values, indicating improved paste stability and resistance to retrogradation. Moisture migration analysis demonstrated restricted water mobility and more homogeneous distribution in treated starch gels. In vitro digestibility was significantly improved, with the EF-SMF treatment increasing rapidly digestible starch by 7.69 % and reducing resistant starch from 38.88 % to 27.62 %, attributed to enhanced molecular accessibility and surface porosity. These modifications are attributed to field-induced structural disordering and increased porosity, demonstrating EF-SMF drying as an effective starch modification strategy.