Effect of oxidized chitin nanocrystals and curcumin into chitosan films for seafood freshness monitoring

Abstract Novel smart films for seafood freshness monitoring were developed by incorporating curcumin (Cur) into a chitosan (CS)/oxidized chitin nanocrystal (O-ChNCs) matrix. O-ChNCs (200–400 nm in length) were prepared from chitin by 2,2,6,6-tetramethylpiperidine-1-oxylradical (TEMPO)-oxidation method and used as reinforcement filler for smart films. The effects of O-ChNCs or Cur addition on the structural, mechanical, barrier and optical properties of Cur/CS/O-ChNCs (Cur-CN) films were investigated. It was found that the incorporation of O-ChNCs and Cur could significantly alter the mechanical, barrier and optical properties of the films. The Cur-CN films showed better barrier properties against water vapor and UV-vis light as well as higher mechanical strength than CS film. Among all the films tested, Cur-CN film containing 10 wt % of O-ChNCs (w/w, CS and O-ChNCs basis) presented the best performance. Morphological analysis by scanning electron microscopy and atomic force microscopy showed that an appropriate amount of O-ChNCs and Cur was well dispersed in the CS films. The electrostatic interactions and hydrogen bonds among CS, O-ChNCs and Cur were confirmed by Fourier transform infrared spectroscopy. Moreover, the colour of Cur-CN films varied with the change in pH, and this characteristic was used to monitor the spoilage of hair tail and shrimp during storage. This study demonstrated that the fabricated smart film has a great potential for use in monitoring seafood freshness.