Active Starch-Polyester Bilayer Films with Surface-Incorporated Ferulic Acid

Abstract

Bilayer films of cassava starch-based (with 10% gellan gum) and polylactic (PLA): Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) polyester blend (with 75% PLA) monolayers were obtained by melt-blending and compression-molding, and the subsequent thermocompressing of both monolayers. Ferulic acid (FA) was incorporated into the polyester sheet by spraying and drying. Films were characterized in terms of their microstructure and functional properties throughout two months of storage at 25 °C and 53% relative humidity. The laminates exhibited improved tensile and barrier properties compared to the respective monolayers, which makes them more adequate for food packaging purposes. Surface incorporation of ferulic acid did not significantly modify the barrier and mechanical properties of the films while providing them with antioxidant and antibacterial capacity when applied in aqueous systems, where a complete release of active compounds occurred. The physical properties of the bilayers and layer thermo-sealing were stable throughout storage. Likewise, the antioxidant and antimicrobial active properties were preserved throughout storage. Therefore, these active bilayers represent a sustainable packaging alternative to non-biodegradable, non-recyclable synthetic laminates for food packaging purposes, which could extend the shelf-life of food due to their antioxidant and antibacterial properties.

Tailoring Pectin-PLA Bilayer Film for Optimal Properties as a Food Pouch Material

“…These characteristics enhance its polarity and chemical affinity with pectin at the interface, leading to favorable interlayer adhesion and stability over time. This was explained in the seal strength analysis conducted between bilayer films of starch and PLA by Hernández-García et al [ 82 ]. Therefore, this demonstrates that the optimized formulation of a bilayer film comprising pectin and PLA can offer excellent heat strength, making it well-suited for packaging materials, particularly for food pouches that require secure sealing.…”

Seal materials in flexible plastic food packaging: A review

“…Seal initiation temperature, peak hot tack temperature and peak hot tack strength are achieved with respective values of 185°C, 135°C and 0.37 N.mm −1 111 . With a 3:1 PLA:PHBV blended seal layer, very low seal strengths around 0.01 N.mm −1 are reported 133 . Sealed films with poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) are used in a shelf life study, but no information is shared on the seal performance and settings 134 .…”

“…Only one setting is considered in that study, and samples are sealed at 140 C and 0.8 s. 127 Properties can be modified by blending, adding fillers and copolymerization, among others. 133 Sealed films with poly(3-hydroxybutyrate-co-4-hydroxybutyrate) are used in a shelf life study, but no information is shared on the seal performance and settings. 134 Another study evaluates chemical structure and molar mass of PHBV, before and after conductive heating, but has not found any changes.…”

Development and Characterization of Thermoformed Bilayer Trays of Paper and Renewable Succinic Acid Derived Biopolyester Blends and Their Application to Preserve Fresh Pasta

“…The seal strength of the bilayer trays was determined in the universal testing machine following the previously developed methodology [ 30 ]. Briefly, the films were heat-sealed on one edge of the paper substrate in a hydraulic press (Model LP20, Labtech Engineering, Bangpoo, Thailand) and protected using Teflon sheets [ 15 ].…”