Properties of Gelatin Film from Horse Mackerel (Trachurus japonicus) Scale

Optimal conditions for extracting gelatin and preparing gelatin film from horse mackerel scale, such as extraction temperature and time, as well as the protein concentration of film-forming solutions were investigated. Yields of extracted gelatin at 70 degrees C, 80 degrees C, and 90 degrees C for 15 min to 3 h were 1.08% to 3.45%, depending on the extraction conditions. Among the various extraction times and temperatures, the film from gelatin extracted at 70 degrees C for 1 h showed the highest tensile strength and elongation at break. Horse mackerel scale gelatin film showed the greatly low water vapor permeability (WVP) compared with mammalian or fish gelatin films, maybe due to its containing a slightly higher level of hydrophobic amino acids (total 653 residues per 1000 residues) than that of mammalian, cold-water fish and warm-water fish gelatins. Gelatin films from different preparation conditions showed excellent UV barrier properties at wavelength of 200 nm, although the films were transparent at visible wavelength. As a consequence, it can be suggested that gelatin film from horse mackerel scale extracted at 70 degrees C for 1 h can be applied to food packaging material due to its lowest WVP value and excellent UV barrier properties. Practical Application In this study, gelatin film from horse mackerel scale at various preparation conditions could be successfully prepared. Horse mackerel scale gelatin films exhibited lower water vapor permeability values than gelatin films from the skin of other fishes or mammals do. Utilization of horse mackerel scale as a raw material of edible film could be solved the environmental pollution by seafood waste during fish processing.