Bio-Based Citrate Plasticizers as Nucleating Agents for PLA Fibers: Unlocking Antioxidant and Antimicrobial Potential

Nano/microfibers are ideal systems for active packaging due to their high surface area, which enables efficient delivery of active compounds, improves food safety and quality, and extends shelf life. Herein, polylactic acid (PLA) fibers were blended with antioxidant and antimicrobial bioplasticizers (CITREM and ACETEM) at 10 wt.% and produced by force spinning using a total polymer concentration of 20 wt.%. The resulting functional fibers were analyzed by Raman confocal microscopy and scanning electron microscopy, which demonstrated uniform fiber formation for most of the bioplasticizer formulations. Thermogravimetric analysis showed a slight decrease in thermal stability associated with plasticizer incorporation, while differential scanning calorimetry revealed a reduction in glass transition temperature and a significant increase in crystallinity, evidencing the nucleating action of CITREM and ACETEM. Antimicrobial activity was evaluated against Gram-positive and Gram-negative bacteria, and antioxidant activity was measured using the Blois method. The results indicate that these bioplasticizers impart new functionalities to PLA, including antimicrobial activity against Gram-positive bacteria and antioxidant properties. These findings provide preliminary evidence that bio-based CITREM and ACETEM can confer bioactive properties to PLA fibers, warranting further investigation of their performance in food contact applications and mechanical characterization to assess their suitability for active packaging.