Manufacture and characterization of gelatin films derived from beef, pork and fish sources using twin screw extrusion

Gelatin films derived from beef, pork and fish sources were manufactured by twin-screw, co-rotating extrusion. The effect of extrusion processing parameters, namely; screw speed (100-400 rpm) and temperature (90, 90, 90, 90 degrees C and 90, 120, 90, 90 degrees C) on the mechanical and barrier properties of gelatin films were studied. Increasing screw speed up to 300 rpm improved (P < 0.05) tensile strength (TS) and reduced (non-significantly) water vapour permeability (WVP) values for all manufactured gelatin films. However, the WVP of various gelatin film types was reduced (P < 0.05) when a screw speed of 400 rpm was employed. Increasing the speed of extrusion promoted (P < 0.05) increased solubility of films in water. Manufacture of films using a higher temperature profile resulted in films possessing higher puncture strengths (PS), increased water barrier properties with higher water solubility. (C) 2012 Elsevier Ltd. All rights reserved.