Properties of ScCO2 Dried Crosslinked Buckwheat Starch‐Based Aerogel Reinforced With TiO2 Nanoparticles

ABSTRACT In this study, aerogels were produced through supercritical carbon dioxide drying using native buckwheat starch (NBS), crosslinked buckwheat starch (CBS), and CBS incorporated with titanium dioxide nanoparticles (TiO 2 NPs) at concentrations of 0.1%, 0.5%, and 1%. NBS aerogel exhibited the lowest bulk density (0.24 g/cm 3 ) and the highest porosity (81.33%), reflecting a loose and open network structure. In contrast, CBS showed an increase in bulk density to 0.27 g/cm 3 and a reduction in porosity to 79.32%, indicating tighter molecular packing due to the formation of inter‐ and intra‐molecular bonds. Further, as the concentration of TiO 2 increased from 0.1% to 1%, bulk density increased from 0.30 to 0.36 g/cm 3 , while porosity decreased from 76.21% to 70.03%. Brunauer–Emmett–Teller (BET) surface area showed a significant increase after crosslinking but declined with rising TiO 2 NPs content. Water absorption also decreased with increasing TiO 2 , correlating with denser matrix formation and reduced availability of hydrophilic sites. However, compressive strength was improved with the addition of TiO 2 incorporation, highlighting its role as a reinforcing agent. Antibacterial activity against Bacillus cereus and Escherichia coli was evident at 1% TiO 2 loading, while antifungal activity against Aspergillus niger was not observed. Overall, this study highlights that incorporating TiO 2 into starch‐based aerogels improves their structural integrity, mechanical strength, and antibacterial activity, but it negatively impacts the bulk density and porosity.