Development and application of novel acetylated starch–chitosan–oregano essential oil active extrudates for meat product microbiological preservation

BACKGROUND: Developing biodegradable active packaging with improved mechanical and antimicrobial properties remains a key challenge in food preservation. This study evaluated the physical and antimicrobial performance of extruded sheets based on a base mixture of acetylated tapioca starch, glycerol and water (BMAS), chitosan (CH) and oregano essential oil (OEO). METHODS: Extruded sheets with varying BMAS, CH and OEO proportions were formulated using a simplex centroid mixture design. Mechanical properties, water solubility, color and thermal behavior were analyzed. Sheets antimicrobial activity was tested in contact with a chicken meat-based food against external contamination by Escherichia coli, Listeria innocua, Enterococcus faecium, or Zygosaccharomyces bailii. RESULTS: ) were identified: central point (853.3 BMAS, 93.3 CH, 53.3 OEO) and S7 (840 BMAS, 80 CH, 80 OEO), both showing the highest stress at break (≈ 1.06 MPa), but maximum (105%) and minimal (26%) deformation, respectively. Water solubility was 40% for central point and 47% for S7. OEO increased mechanical resistance but reduced solubility compared to controls without oil. Acetylation improved tensile strength, solubility and whiteness, though slightly decreasing thermal stability. Regarding antimicrobial barrier action, the effectiveness was microorganism dependent: while Z. bailii was not detected along storage, Escherichia coli was more sensitive than L. innocua and Enterococcus faecium. CONCLUSION: The present findings indicate that the developed extrudates are promising candidates for biodegradable active food packaging. The retained availability of OEO effectively contributed to microbial spoilage control, with Z. bailii and Escherichia coli exhibiting greater susceptibility compared to L. innocua and Enterococcus faecium.