Comparison of the properties of multi-composite fish gelatin films with that of mammalian gelatin films.

Four types of films viz. gelatin, gelatin-MMT, gelatin-chitosan and gelatin-MMT-chitosan prepared from redsnapper and grouper bone gelatin were compared with the mammalian gelatin films, for their mechanical and barrier properties. Grouper gelatin films had higher tensile strength (TS) and Young's modulus (YM), but lower elongation at break (EAB) than redsnapper films. Incorporation of MMT and chitosan improved the TS (p<0.05) of the films. Water solubilities were lower (p<0.05) in films incorporated with chitosan compared to simple gelatin film. Protein solubilities were lower in gelatin-MMT films, irrespective of the type of solvent used. The water vapour transmission rates (WVTR) of fish and mammalian gelatin films were similar, but addition of MMT had reduced WVTR (p<0.05). SEM micrographs depicted smoother surface for gelatin-MMT and gelatin-MMT-chitosan films. Thus, composite fish gelatin films made with MMT and chitosan could be the good natural biodegradable films due to their better mechanical and barrier properties.