Production of active film based on potato starch containing Zedo gum and essential oil of Salvia officinalis and study of physical, mechanical, and antioxidant properties

Abstract

In this study, biodegradable/antioxidant active film based on potato starch was provided. Composite films of potato starch/Zedo gum/ Salvia officinalis essential oil were provided in different percents of Zedo gum (0.5–1.5%) and S. officinalis essential oil (0–500 µl). The characters of composite film, including physical, mechanical, and antioxidant properties were studied. The results showed that adding different amounts of Zedo gum and essential oil to starch film causes a significant decrease ( p < 0.05) in moisture content, solubility, and film water vapor permeability (WVP). The film containing 1.5% gum and 500 µl of essential oil had minimum moisture content, solubility, and WVP. Results showed that the addition of Zedo gum significantly increased the thickness and opacity of the films and reduced the transparency of the films. Increasing the essential oil is significant on the film opacity and leads to a decrease in the passage of light from the films. By adding different amounts of gum, the antioxidant content of the films was significantly increased compared to the control film (pure starch film). Also, increasing the concentration of essential oil in the film composition caused a significant increase in the antioxidant activity of the films ( p < 0.05). Modified starch films containing 1.5% gum (without essential oil) with 62.64% antioxidant activity and film with 1.5% gum and 500 µl essential oils with 68.35% antioxidant activity had the highest antioxidant activity. The addition of salvia essential oil and Zedo gum significantly decreased the elongation and tensile strength of the potato starch film ( p < 0.05). Finally, the potato starch composite film containing Zedo gum and salvia essential oil showed excellent physical and antioxidant properties and had an excellent ability to be used in the food packaging industry.