Curcumin-sensitized TiO2 composite photocatalyst: Synthesis, characterization and photocatalytic preservation performance on red shrimp (Solenocera crassicornis).

A curcumin (Cur)-sensitized food-grade titanium dioxide (TiO2) composite photocatalyst, TiO2@Cur, was successfully constructed via rotary evaporation. Spectral analyses revealed that curcumin sensitization extended the light absorption range of TiO2@Cur from the ultraviolet to the visible region and markedly reduced its band gap to 2.42 eV. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope/energy dispersive spectrometer (SEM/EDS) analyses confirmed the uniform loading of curcumin into the porous structure of TiO2. Furthermore, TiO2@Cur exhibited a high aqueous solubility of 3700.10 ± 141.42 μg/mL (∼10-fold that of free curcumin), and its aqueous solution remained stable without noticeable precipitation. Notably, TiO2@Cur demonstrated a strong capacity to generate singlet oxygen (1O2) and hydroxyl radicals (•OH). In the 4 °C preservation application, refrigerated red shrimp treated with TiO2@Cur-mediated photocatalytic preservation received the highest sensory evaluation scores and color protection effect. Moreover, TiO2@Cur could effectively control the increase of freshness indicators, including total volatile basic nitrogen (TVC-N) content, pH value, total viable bacteria count (TVC), and malondialdehyde (MDA) content, which were 24.04 ± 0.67 mg/100 g, 7.44 ± 0.02, and 5.72 ± 0.06 lg CFU/g on the 6th day of storage respectively. Additionally, TiO2@Cur significantly suppressed the oxidation of proteins and lipids, with a total protein content of 5.49 ± 0.07 g/L. Meanwhile, it could effectively inhibit the water loss of refrigerated shrimp. Therefore, TiO2@Cur-mediated photocatalytic preservation treatment significantly extended the refrigerated shelf life to 6 days, demonstrating its potential as a novel seafood preservative with promising applications.