Packaging is vital for protecting food, but the migration of unwanted substances from packaging can compromise safety and quality. Bio-based plasticizers, derived from natural sources, offer a safer alternative to conventional plasticizers due to their low toxicity.
Vegetable oil-derived bio-plasticizers, including citric acid esters of mono- and diglycerides (CITREMs), were tested as plasticizers for the first time, alongside ACETEM. Films made from poly(lactic acid) (PLA) and Ecovio (a blend of PLA and poly(butylene adipate-co-terephthalate) PBAT) were prepared using 10% bio-based plasticizers through melt extrusion and compression molding. These films were evaluated for thermal, mechanical, antimicrobial, and antioxidant properties.
Thermal properties were measured using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Mechanical properties were tested with tensile testing, while antimicrobial properties were assessed against bacteria like Staphylococcus aureus and Listeria innocua. Antioxidant properties were also analyzed, with additional insights from Raman confocal microscopy.
CITREM-LR outperformed other plasticizers, improving antioxidant and antimicrobial properties, as well as mechanical performance in both PLA and Ecovio films, without affecting thermal properties. Raman microscopy showed that CITREM-LR formed microdomains in PLA that aligned in the crack direction, further enhancing mechanical strength. While ACETEM SOFT-NSAFE exhibited antimicrobial activity, it had lower antioxidant properties and offered less mechanical improvement.
All films, including those with CITREM-LR and ACETEM SOFT-NSAFE, retained their biodegradability and compostability under industrial conditions. These films successfully biodegraded during composting. confirming their potential as eco-friendly packaging materials.
In summary, bio-based plasticizers, especially CITREM-LR, show great potential for sustainable food packaging by enhancing antimicrobial and antioxidant properties and mechanical performance while reducing environmental impact and maintaining food safety and quality.

Enrique Blázquez Blázquez

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