Investigating the Functional, Mechanical and Structural Characteristics of Soy Protein Isolate Biodegradable Film Containing Nanoclay (Montmorillonite) and Salvia officinalis Essential oil

In this research, production films based on soy protein were produced with two variables of nanoclay at three levels (0, 0.5 and 1%) and Salvia officinalis Essential oil at three different levels (0, 250 and 500 ppm) and the effect of this Two variables were investigated on the functional, mechanical and structural characteristics of the produced biodegradable films. The results showed that by adding different percentages of nanoclay on the soy protein film substrate, the moisture content, solubility, permeability to water vapor and transparency of the samples decreased significantly compared to the control sample. This decrease in indicators was more evident with increasing concentration of Salvia officinalis Essential oil. Among the production samples, the film containing 1% nanoclay and 500 ppm of Salvia officinalis Essential oil had a water vapor permeability of 32.02´10-11 g/m.s.pa. Also, the addition of nanoclay and Salvia officinalis essential oil caused a significant increase in the antioxidant content of the samples, and the sample containing 1% nanoclay and 500 ppm of Salvia officinalis essential oil had the highest antioxidant content with 32.88%. Examining the results of spectroscopy and microstructure of the obtained films also shows the proper interaction between nanoparticle and essential oil with soy protein substrate and creating strong and new bonds. The obtained results showed that the addition of nanoclay and Salvia officinalis essential oil can have positive effects on the physical and structural properties of soy protein isolate film.