Supercritical CO2 impregnation of PLA/PCL films with natural substances for bacterial growth control in food packaging
Veröffentlichungsdatum
2018-03-21
Zusammenfassung
Biodegradable polymers with antibacterial properties are highly desirable materials for active food packaging applications. Thymol, a dietary monoterpene phenol with a strong antibacterial activity is abundant in plants belonging to the genus Thymus. This study presents two approaches for supercritical CO2 impregnation of poly(lactic acid)(PLA)/poly(ε-caprolactone)(PCL) blended films to induce antibacterial properties of the material: (i) a batch impregnation process for loading pure thymol, and (ii) an integrated supercritical extraction-impregnation process for isolation of thyme extract and its incorporation into the films, operated in both batch or semi-continuous modes with supercritical solution circulation. The PCL content in films, impregnation time and CO2 flow regime were varied to maximize loading of the films with thymol or thyme extract with preserving films' structure and thermal stability. Representative film samples impregnated with thymol and thyme extract were tested against Gram (-) (Escherichia coli) and Gram(+) (Bacillus subtilis) model strains, by measuring their metabolic activity and re-cultivation after exposure to the films. The film containing thymol (35.8 wt%) showed a strong antibacterial activity leading to a total reduction of bacterial cell viability. Proposed processes enable fast, controlled and organic solvent-free fabrication of the PLA/PCL films containing natural antibacterial substances at moderately low temperature, with a compact structure and a good thermal stability, for potential use as active food packaging materials.
Schlagwörter
Antibacterial food packaging
;
Poly(lactic acid)
;
Poly(ε-caprolactone)
;
Supercritical CO(2) impregnation
;
Thyme extract
;
Thymol
Verlag
Elsevier {BV}
Institution
Dokumenttyp
Artikel/Aufsatz
Zeitschrift/Sammelwerk
Band
107
Startseite
486
Endseite
495
Seitenzahl
10
Zweitveröffentlichung
Ja
Dokumentversion
Postprint
Sprache
Englisch
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Name
MILOVANOVIC - Supercritical CO2 impregnation of PLA.pdf
Size
1.43 MB
Format
Adobe PDF
Checksum
(MD5):3adde0cb8d6b9b4d844b8e1cea558632