Production of biodegradable film based on beta-glucan/polycaprolactone modified with extract of oak fruit pair, apricot kernel and gold nanoparticles: Investigation of physicochemical and antioxidant properties

<title>Abstract</title> In this study, a polycaprolactone (PCL) and beta-glucan (BG) composite film was prepared. Oak fruit pair extract (OFPE) and apricot kernel extract (AKE) and gold nanoparticles (AUNPs) were used to modify the structure of the composite film. The physicochemical, structural and antioxidant properties of the prepared films were investigated. The results showed that gold nanoparticles had the greatest effect on increasing the film thickness, followed by OFPE extract. In terms of physical properties, gold nanoparticles played a major role in changing the film moisture content, and both OFPE and AuNPs significantly affected the solubility. The investigation of mechanical properties showed that all three factors significantly increased the tensile strength. In terms of flexibility, AKE was identified as the most important factor with a coefficient of + 49.38. In terms of appearance, all additives significantly reduced the lightness and increased the opacity of the film. Antioxidant activity analysis showed that OFPE was the strongest factor and AKE also contributed greatly to increasing the antioxidant activity. SEM studies showed that the addition of extracts created porosity and a spongy structure, while gold nanoparticles led to the formation of a more compact and uniform surface. FTIR analysis confirmed the formation of hydrogen bonds between the functional groups of the materials and the polymer matrix. XRD results showed a decrease in the degree of crystallinity and an increase in the amorphous phase with the addition of extracts, while the distinct peaks related to gold nanoparticles confirmed their presence and stability in the composite structure. TGA analysis showed an improvement in thermal stability in the presence of gold nanoparticles and a decrease in thermal stability with the addition of extracts. These composite films, with their desirable physicomechanical, antioxidant and thermal properties, have high potential for use in active food packaging.