Effect of dual modification on physicochemical, structural properties and functional groups distribution of corn...

This study investigates the dual modification of corn starch through oxidation using sodium hypochlorite (1.5 and 5 % w/v) and cross-linking with calcium chloride (5-15 g/l) to enhance its structural, physicochemical, thermal properties, and functional group distribution. The results showed that cross-linking reduces carboxyl groups (0.452 to 0.039) through electrostatic interactions, affecting corn starch water absorption, solubility, and swelling power. Advanced instrumental analyses confirmed that FTIR indicated functional group stabilization, DSC showed enhanced thermal stability with gelatinization temperatures rising from 75.76 to 80.22 °C, and TGA demonstrated increased thermal resistance. XRD analysis revealed partial amorphization and chain reorganization, while SEM highlighted granule smoothing and improved surface integrity. The dual-modified starches showed enhanced solubility, transparency, and paste stability, making them suitable for food industry applications such as thickeners and film-forming agents. This study highlights the synergistic effects of oxidation and cross-linking, offering valuable insights into the molecular mechanisms of starch modification and paving the way for future research to optimize these processes for broader industrial use.