Effect of interactions of locust bean gum and rosehip juice on the physical properties of gum tragacanth composite films

The aim of the study was to demonstrate the synergistic effect of natural polysaccharide hydrocolloids of locust bean gum and tragacanth gum combined with rosehip juice. It was shown that tragacantha gum has an excellent film-forming properties at low concentration and forms water-soluble, thin and transparent edible films with high application potential, which was demonstrated by selected physical properties of composite films obtained from a mixture of gum tragacanth and locust bean gum. Optical (color and opacity), thermal (thermogravimetric analysis), water vapor permeability and sorption kinetics were determined. The thickness of the films depends on the composition of the films, the process conditions, as well as the application techniques. The addition of locust bean gum resulted in an increase in the water content and consequently more elastic and less brittle gum tragacanth films. Films made only of gum tragacanth were characterized by greater hygroscopicity, as opposed to composite films. As the concentration of gum tragacanth increases, the value of water vapor permeability also increases, and the share of locust bean gum in the films caused the permeability to decrease. Composite films had a lighter color compared to those of pure gum tragacanth, and the carob contributed to a more transparent film and slower thermal degradation. In the films obtained, a synergistic effect was observed between the biopolymers in all the ratios used, and the addition of locust bean gum and rosehip juice had a strong influence on the properties of the obtained edible films. Practical applications The potential of using gum tragacanth to create edible films and coatings through their appropriate modification and optimization of the composition ratio of the created composites can become a challenge for their use in the food packaging industry. This study will be constructive for further research work focused on films and coatings and their application as protective coatings or bio-based packaging films.