Physical influences effect on the microstructure of fish gelatin membrane

The results of studies on the effect of temperatures ranging from 100 to 140 °C, aqueous and alcoholic solutions, and UV radiation on the microstructure of foamed membrane based on fish gelatin are presented. Fish gelatin – a structure forming agent made from fish collagen containing raw materials (skin, swim bladders, and scales of fish from the Volga Caspian basin) – was used as the main ingredient for making the membrane; it complies with the regulatory safety and quality requirements for food products. It has similar functional and technological properties, chemical composition, and structure to traditional gelatin, but it is characterized by a lower (by 4 °C) melting point of the jelly and safety in terms of eliminating the risk of prion disease agents and human infection by mammalian diseases. The study of the stability of the structure of the developed films under physical stress was conducted in the context of the growing interest in developing environmentally friendly packaging materials that are resistant to external factors that may arise during the production and use of food packaging. It has been established that a film based on fish gelatin in dry form (moisture content 16-20%) can be subjected to convective heat treatment with air at a temperature ranging from 100 to 140 °C; this does not cause any changes to the porous structure and results in increased moisture resistance of the membrane. This occurs due to the structuring of the polymer system of the fish gelatin molecule, which is accompanied by an enhancement of intra- and intermolecular interactions. Increasing the heat treatment temperature to 160-180 °C leads to changes in the structure of the developed membrane, a reduction in the size of the cavities, and their sintering. Exposure to aqueous solutions of sodium benzoate and ethyl alcohol, using the methods of spraying and immersion, does not have a negative effect on the structure of the heat-treated membrane. Ultraviolet radiation also does not cause structural changes in the membrane samples. The obtained results substantiate the stability of the developed membranes to the specified types of external influence and demonstrate the potential for their use for food, cosmetic, and medical purposes.