Extraction of chitosan from fish scale for food preservation and shelf-life enhancer

Abstract

With the increasing demand for chitosan in various applications and the drawbacks associated with crustacean shell-based chitosan, there is a need to seek for alternative sources for the extraction and production of chitosan. In this study, extraction of chitosan from the scales of red snapper (Lutjanus johnii) was performed. It was observed that the concentration of solvent (HCl and NaOH) and temperature at different stages of extraction process affected the yield of the extracted fish scale chitosan obtained. The characterization result revealed that similar Fourier-transform infrared spectroscopy (FTIR) spectra was observed between the commercial crustacean-based chitosan and the extracted fish scale chitosan, evidencing similar functional groups between the two. The degree of deacetylation (DDA) of the extracted fish scale chitosan was determined to be 76.9 %, with the ash value, loss on drying and solubility at 1.28 %, 3.62 % and 88.8 %, respectively. All characterization results indicated similarities between the extracted and the commercialized chitosan. The potential of fish scale chitosan to be used as a food preservative and shelf-life enhancer was subsequently explored in this study. Strawberries coated with chitosan were kept at different temperatures and the physical appearance and moisture loss was recorded. It was observed that fish scale chitosan was able to prevent up to 50 % moisture loss in strawberries when it was applied in conjunction with the conventional preservation technique such as storage in a cool environment.