Soluble soybean polysaccharide/TiO2 bionanocomposite film for food application

Abstract

In the current study, a set of biodegradable soybean polysaccharide (SSPS) nanocomposites containing different ratios of TiO₂ nanoparticles was characterized as new packaging system. X-ray diffraction (XRD) measurement showed that the crystalline structure of the TiO₂ nanoparticles remained intact in the polysaccharide matrix and the surface of nanocomposites containing 1-3% TiO₂ was observed morphologically uniform under scanning electron microscopy (SEM). Dynamic mechanical thermal analysis revealed that the magnitude of storage modulus was 3.62-fold higher in SPSS/TiO₂ nanocomposites containing 7 wt.% of TiO₂ than control SSPS indicating improvement in the physical properties of the film supposed to be utilized for food packaging. With respect to the concern over the safety of these nanocomposites, inductively coupled plasma-optical emission spectroscopy (ICP-OES) showed that no TiO₂ was detected in bread samples covered by SSPS/TiO₂ film and stored for 6 months. Similarly, the nanocomposite films only released a minuscule amount (21.05 ± 0.054 ppm) of TiO₂ in water. TiO₂ nanoparticles were found in the plasma membrane of epithelial cell line after long-term exposure (10-day) of these cells to large amounts of the free nanoparticles. SSPS/TiO₂ nanocomposites showed excellent antimicrobial activity against Staphylococcus aureus PTCC 1431 (ATCC 25923), while neither anti-cancerous nor pro-cancerous activity was observed for these nanocomposites denoting their neutrality with respect to cancer suppression or progression in gastrointestinal tract. In conclusion, SSPS/TiO₂ nanocomposites could be a promising packaging system for food industries' objective regarding their physical characteristics, low rate of Ti transition, and low health risk.

Keywords: Antimicrobial activity; Migration; Soybean polysaccharide; TiO(2) nanoparticles.