DEVELOPMENT OF HALOCHROMIC SENSOR FOR MONITORING SPOILAGE OF PACKAGED FISH

The quality of fishes available in the market is assessed by simple sensory evaluation of gill and odour. The undesirable odour of spoiled fish is due to evolution of total volatile amines. However, the sensory evaluation technique fails in the case of packaged fish since consumer can neither touch the fish nor sense the odour. In this study, a bionanocomposite that exhibit halochromism is developed for monitoring spoilage of packaged fish. At first, a natural dye was extracted and used to prepare metal nanoparticles via an in situ method. Then the nanoparticles were blended with 5-10 wt% of polymers of natural origin and casted into thin film.  These thin films were characterized by UV-visible spectroscopy, FT-IR spectroscopy, X-ray diffraction, Scanning Electron Microscopic (SEM) techniques. The halochromic behaviour of the thin films was examined at different pH.

The UV-visible spectrum of the bionanocomposite exhibited a brand band at 420 nm. Several peaks were observed in the region of 1750 - 1640 cm^-1 in FT-IR spectrum of the bionanocomposite. SEM morphologies of the bionanocomposite showed presence of nanoparticles having average size of 70 ± 15 nm. The nanocomposite developed different colors for different pH ranging from 1 - 14.

The UV-visible and FT-IR spectral analyses indicated the successful incorporation of the natural dye into the thin film. The presence of silver nanoparticles was indicated by the SEM and X-ray diffraction analyses. The CIE L*a*b and RGB values of the colors developed at different pH by the nanocomposite suggested that the developed halorchmic sensor could be used to monitor fish spoilage.