The physicochemical and structural properties of pulsed electric field pretreated acid-thinned native corn starch

Conventional thermal and chemical methods for food processing often result in undesirable changes to food quality, such as nutrient loss and altered functional properties. Pulsed electric field (PEF) treatment has emerged as a promising non-thermal technology that can help mitigate these downsides. This study aims to investigate the potential of combining PEF treatment with hydrochloric acid thinning to modify the properties of native corn starch (NS). NS was subjected to PEF treatment (18 kV/cm, 300 Hz, 10 μs, 8 min, 2 mL/s) followed by acid thinning using HCl (0.1 M/0.2 M, 50 °C, 3 h). The physical and chemical structures of the treated starch were analyzed using SEM, XPS, DSC, TGA, FT-IR, and XRD. The results indicated that while acid thinning of NS (ATNS-0.1M) increased the gelatinization onset temperature, the combination of PEF treatment and acid thinning significantly decreased the gelatinization temperatures and enthalpy required for gelatinization, particularly with higher acid concentrations (ATPS-0.2M). This suggests a preferential degradation of amorphous regions, destabilizing the starch structure. XRD results confirmed a decrease in crystallinity in the dual-treated samples compared to NS. FT-IR, TGA, and rheological measurements showed that the dual-treated samples significantly reduced the retrogradation degree, decomposition temperatures, and viscosities, suggesting a reduction in intermolecular interactions within the starch granules. Overall, this study provides valuable insights into the potential of combining PEF and acid thinning as an effective method for reducing viscosity and enhancing the functional properties of starch, offering a viable alternative to conventional processing methods.