Effects of genipin as natural crosslinker on barrier and mechanical properties of chitosan‐astaxanthin film

The aim of this research was to study the effect of genipin crosslinking (0.5, 1.0, and 1.5% (w/w of chitosan)) on moisture barrier property and mechanical strength of chitosan-astaxanthin film. The film functional properties including transparency, tensile strength (TS), elongation at break (EB), water transmission rate (WVTR), and oxygen transmission rate (OTR) were investigated. The results showed that genipin crosslinking was significantly decrease the film transparency and %EB while OTR slightly increased. Fourier transform infrared observation on the chemical-crosslinking structure showed the shifted peak at 1,720 and 1,569 cm−1, indicating the forming covalent linkage between chitosan and genipin. The morphology characterization of the film was evaluated by scanning electron microscopy and found that the crosslinked film was a rougher surface than non-crosslinked film. Chitosan-astaxanthin film with crosslinking of 1% (w/w) genipin significantly improved WVTR and TS compared to other samples. Novelty impact statement Active biodegradable packaging made from chitosan, such as chitosan film incorporated with natural antioxidants, is preferred but lack the water barrier and strong mechanical properties necessary for high moisture food application. In this study, genipin-crosslinking is not only a promising technique to improve the performance and applicability of our developed chitosan-astaxanthin film, but genipin is also a natural crosslinker and an alternative to most chemical crosslinkers which cause undesirable changes and cytotoxicity.