Structure and properties of ozone-induced Schiff-base crosslinked starch-chitosan complex under ozone duration

This study investigates the regulatory effect of ozone-induced Schiff base crosslinking on the structure and properties of a chitosan/waxy rice starch composite system. By varying the ozone treatment duration (0-60 min), changes in chemical structure, crystalline characteristics, thermal stability, and gel properties were systematically analyzed. Structural characterizations including FTIR and NMR confirmed the formation of Schiff base bonds and structural rearrangement. SEM and rheological analysis indicated that ozone optimized the pore structure and rheological properties of the gel, endowing it with excellent extensibility and coating performance. Results indicate that short-term ozonation (≤30 min) promotes crosslinking between carbonyl and amino groups, significantly enhancing the composite's molecular weight, crystallinity, and thermal stability. Conversely, excessive oxidation (≥45 min) causes chain scission and performance degradation. This study elucidates the structural evolution mechanism of chitosan/starch composites under ozone treatment, providing theoretical foundations for designing green, controllable crosslinking and edible functional materials.