Photocatalytic degradation of patulin in apple juice based on nitrogen-doped chitosan-TiO2 nanocomposite prepared by a new approach

Abstract

A high-performance nitrogen-doped chitosan-TiO2 nanocomposite to be used as a photocatalyst for patulin degradation in apple juice was successfully prepared by a simple precipitation method. The structure and properties were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), and UV–Vis diffuse reflectance spectrum. According to XPS and UV–Vis analyses, nitrogen had been successfully doped into the TiO2 nanoparticle crystals and reduced the band gap energy of TiO2 nanoparticles. The synthesized nanocomposite was able to photocatalytically degrade the patulin in apple juice under ultraviolet irradiation. The patulin (500 μg/kg) was completely degraded within 35 min, which exhibited significantly enhanced photocatalytic activities compared with TiO2 nanoparticles or chitosan-TiO2 nanocomposite. Moreover, the photocatalytic treatment significantly reduced the occurrence of juice browning, and had little effects on reducing sugar, pH, titratable acid and soluble solids of the apple juice. The nitrogen-doped chitosan-TiO2 nanocomposite would be an ideal photocatalyst for patulin degradation in apple juice due to its high photocatalytic activity and little effects on the quality of apple juice.