Title: Effects of Drying Temperature on Barrier and Mechanical Properties of Cold-Water Fish Gelatin Films Authors
Submitted to: Journal of Food Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 16, 2009
Publication Date: November 1, 2009
Citation: Chiou, B., Avena Bustillos, R.D., Bechtel, P.J., Imam, S.H., Glenn, G.M., Orts, W.J. 2009. Effects of Drying Temperature on Barrier and Mechanical Properties of Cold-Water Fish Gelatin Films. Journal of Food Engineering. 95(2), 327-331. Interpretive Summary: We examined mechanical, thermal, and barrier properties of Alaska pollock and Alaska pink salmon gelatin films dried below (cold-cast) and above (hot-cast) their gelation temperatures. Cold-cast fish gelatin films exhibited comparable mechanical and thermal properties to mammalian gelatin films. This was due to formation of helical structures in cold-cast films. Also, cold-cast films had higher water sorption values than hot-cast films at different relative humidity, resulting in worse water barrier properties. In addition, water barrier properties depended on helical structure content rather than source of gelatin.
Technical Abstract: Fish gelatin films made from Alaska pollock (Theragra chalcogramma) and Alaska pink salmon (Oncorhynchus gorbuscha) were dried at 4C, 23C, 40C, and 60C. The tensile, thermal, thermal stability, water sorption, and water vapor permeability properties were examined for cold-cast gelatin films (dried below gelation temperature at 4C) and hot-cast gelatin films (dried above gelation temperature at the higher temperatures). Cold-cast gelatin films retained helical-structured gelatin, whereas hot-cast gelatin films were amorphous. This resulted in cold-cast gelatin films having higher tensile strength and percent elongation values than hot-cast gelatin films. Also, water sorption isotherms indicated cold-cast gelatin films had higher equilibrium moisture contents than hot-cast gelatin films, except at low and high relative humidity. In addition, cold-cast gelatin films had water vapor permeability values two to three times higher than those of hot-cast gelatin films. The higher water vapor permeability values might in part be due to higher moisture contents found in cold-cast gelatin films.