Development of a high-barrier, antimicrobial, and pH-sensitive nanocomposite film based on gellan gum/sodium carboxymethylcellulose/sodium alginate with nano-SiO for strawberry preservation and monitoring.

In this study, pH-responsive nanocomposite films with high barrier properties were obtained by the addition of a mixture of methyl red and bromothymol blue to the inner film and Silicon dioxide nanoparticles (nano-SiO) to the outer film matrix. The incorporation of nano-SiO resulted in a notable reduction in the oxygen permeability coefficient and water vapor transmission rate, accompanied by an enhancement in the UV barrier and tensile strength. In comparison with the control sample (0 % nano-SiO), the film containing 1 % nano-SiO exhibited a 57.1 % decline in the oxygen permeability coefficient, a 33.6 % rise in tensile strength, and a reduction in the water vapor permeability coefficient to 2.32 × 10 gsPa. Meanwhile, the film with incorporated nano-SiO demonstrated enhanced thermal stability and augmented free radical scavenging capacity. The color of all films exhibited notable alterations in response to fluctuations in pH and CO concentrations. The application of a bilayer film to strawberry packaging allowed the freshness of the strawberries to be evaluated based on visible color change to the naked eye. The results of the experiment demonstrated that the addition of the nano-SiO film served to maintain the intrinsic physicochemical characteristics of the strawberries, while simultaneously extending their shelf life. In conclusion, the 1 % nano-SiO film has the potential for a wide range of applications.