Porous spontaneously polarized ceramic-reinforced ozone micro-nano bubbles for efficient oxidation of starch: Reaction uniformity, physicochemical properties, and mechanism

Abstract

The preparation of food-grade oxidized starch with eco-friendly ozone (O₃) as oxidant is limited by low mass transfer and reaction efficiency. This study proposed a porous spontaneously polarized ceramic-reinforced O₃ micro-nano bubbles (PSPC-OMNB) technology to prepare oxidized cassava starch (PSPC-OMCS). Meanwhile, reaction uniformity, physicochemical properties, and formation mechanisms were emphasized for comprehensive investigation. PSPC-OMNB enhanced starch oxidation by improving mass transfer and activating reactive sites in molecular chains. PSPC-OMCS with superior oxidation uniformity exhibited favorable physicochemical properties. The oxidation mechanism illustrates that local electric field of PSPC-OMNB enhanced O₃ adsorption-decomposition to generate hydroxyl radicals and simultaneously diminished hydrogen bonding of H₂O to form small water clusters, which effectively promoted uniform distribution of oxidized groups in the C₂, C₃, and C₆ sites along starch molecular chains. This study proposes great promise for achieving reaction uniformity in efficient oxidation of starch.

Keywords: Outstanding physicochemical properties; Oxidized starch; Ozone micro-nano bubbles; Porous spontaneously polarized ceramic; Uniform oxidation mechanism.