Fish gelatin films show good packaging potential
The study, Gelation, Oxygen Permeability, and Mechanical Properties of Mammalian and Fish Gelatin Film, sought to examine and evaluate the advantages of different mammalian, warm-and-cold-water fish gelatin solutions and films.
The study found significant differences in the properties of the mammalian and warm-and-cold-water fish solutions and films they tested.
Researchers believe the low gelation, low melting temperature and low oxygen permeability of the cold-water fish gelatin they tested, would make it an ideal material for food packaging.
“The low oxygen permeability properties of fish gelatin films and in particular, cold-water fish gelatin films, could be useful for applications where reduced oxidation in gel-encapsulated drugs and in refrigerated, frozen, and dried food systems was required” said the research.
Oxygen is involved in many degradation reactions in foods, so inevitably packaging strategies will seek to exclude oxygen to protect food products.
While the study suggested the fish gelatin films have inferior tensile and puncture properties, the researchers believe this could be improved through the use of different types and concentrations of plasticisers.
Methods
Gelatin solutions and film castings from Alaska pollock and pink salmon fish skin were compared with two from commercial cold-water fish (derived from pollock, cod or haddock), a warm-water fish (catfish), and five mammalian examples.
They were prepared using an extraction procedure before being made into a solution by dissolving 7.5g of gelatin in 105ml of distilled water and mixing it for 5 minutes at 500rpm.
The solution was heated in a water bath at 60°C for an hour, degassed, poured onto a flat Mylar film placed over a glass plate, and left it to dry overnight at 23°C.
The marine and mammalian casting films were then peeled from the Mylar film to test their oxygen permeability and their thermal, mechanical and gelation properties.
Oxygen barrier potential
The films were tested for oxygen permeability by placing circular pieces of the film into a test cell and being exposed to 98% Nitrogen and 2% Hydrogen on one side and pure oxygen on the other.
The cold-water fish samples produced low oxygen permeability “significantly lower than those mammalian gelatin films.”
The researchers added, “Lower oxygen permeability of cold-water fish gelatin films could lead to new applications, such as coatings and capsules in food and drug industries to reduce oxidation and increase shelf life.”
Gelation, Oxygen Permeability, and Mechanical Properties of Mammalian and Fish Gelatin Film by J.B. Avena-Bustillos, B. Chiou, C.W. Olsen, P.J. Bechtel, D.A. Olson, and T.H. McHugh in the Journal of Food Science. doi: 10.1111/j.1750-3841.2011.02312.x
