Polyethylene nanocomposite films containing combinations of organoclay (OC) nanoparticles were prepared using extrusion molding method. The physical (X‐ray diffraction [XRD] and scanning electron microscopy [SEM]), mechanical (tensile strength [TS] and elongation at break [E]) and antibacterial properties of the films against gram positive and gram negative bacteria were evaluated. XRD results showed an increase in basal reflection and intercalated‐exfoliated structure prepared. SEM images revealed that Cloisite 20A had better compatibility with the polyethylene matrix in such way that it distributed homogenously in the matrix. Incorporating nanoparticles into polyethylene matrix significantly improved mechanical properties of the films in terms of TS and E parameters. Among used organoclays, Cloisite 30B, and Cloisite 15A had the most and the least antibacterial effect, respectively. A combination of three studied OCs revealed a more pronounced antibacterial effect than that of single or binary mode. Furthermore, its effect on gram negative Escherichia coli, was more pronounced than gram positive Staphylococcus aureus. Practical applications Nanocomposite films studied in this research provide bacteriostatic activities with improving mechanical properties. The main feature of this study was to use a mixture of nanoparticles for an enhanced antibacterial effect and, therefore, to reduce metallic nanoparticles' concentration in the obtained active films. Thus, such packaging material is suggested for potential use as an optimal choice for antimicrobial food packaging applications.

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Polypropylene (PP) based active composite films were prepared by adding butylated hydroxy anisole (BHA), butylated hydroxytoluene (BHT), and tertiary butylated hydroquinone (TBHQ) antioxidants using the extrusion molding process. All concentrations of BHT, 2% to 3% BHA, and 3% TBHQ significantly increased the tensile strength (TS) of the composite films compared with control films. Increasing antioxidant concentration decreased TS values for BHT films, whereas an opposite trend was observed for BHA and TBHQ films. BHA at < 2%, BHT at > 2%, and TBHQ at all added concentrations significantly reduced elongation at break (Eb) of the composite films compared to control films. Water vapor permeability (WVP) of 1% BHT film was not significantly different from control. However, other antioxidants especially at increased concentrations significantly increased WVP values. TBHQ films with 300% to 662% increase had the highest WVP and BHT films with 5% to 81% increase had the lowest WVP among composite films. All three antioxidants had a negative effect on the transparency of the films; however the effect of BHA at higher concentrations was greater. The antioxidants did not change the color attributes of the films. Films containing all antioxidants showed 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging activity, which increased with increase in their concentration, especially for those containing 3 wt.% BHT and TBHQ. Overall, incorporating BHA and BHT into a PP matrix improved mechanical, barrier, antioxidant properties, and film appearance and consequently were proposed for the development of antioxidant active PP films. TBHQ film is not recommended for food packaging because of its weak mechanical properties (lower Eb and TS values, higher WVP, and greater migration).

To extend the shelf-life of packaged donut without the addition of preservative, polypropylene-based active composite films loaded with a combination of sorbic acid, BHA and BHT were prepared by the extrusion moulding method: T1 (Control-pure PP-film), T2 (PP-BHT1%-SA2%), T3 (PP-BHA3%-SA2%) and T4 (PP-BHT1%-BHA1%-SA2%). The incorporation of active additives enhanced water vapour permeability (WVP) and increased oxygen permeability of films. Active films had higher antioxidant activity than pure PP in the order T4 > T2 > T3 (89.11, 83.40 and 79.16%). In vitro examinations demonstrated a significant antibacterial effect on Escherichia coli and S. aureus growth. Overall migration was not significantly different for watery food simulants, while in acidic and fatty foods increased it significantly. The effect of the active films on the fried and packaged donut samples showed significantly higher moisture contents and peroxide values, while acidity was lower. T2 film is proposed due to the preservation of the intrinsic properties of the film, increasing the storage period up to 25 to 50 days.

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