Characterization of active and pH-sensitive poly(lactic acid) (PLA)/nanofibrillated cellulose (NFC) films containing essential oils and anthocyanin for food packaging application

• Published in: International journal of biological macromolecules Vol. 212; pp. 220 - 231
• Main Authors: Zabidi, Nurul 'Afifah, Nazri, Farhana, Tawakkal, Intan Syafinaz Mohamed Amin, Basri, Mohd Salahuddin Mohd, Basha, Roseliza Kadir, Othman, Siti Hajar
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2022
• Subjects: Anthocyanin; Anthocyanins; Cellulose - chemistry; Essential oil; Food Packaging; Hydrogen-Ion Concentration; Nanofibrillated cellulose; Oils, Volatile - chemistry; pH indicator; Poly(lactic acid); Polyesters - chemistry; Thymol; Anthocyanin; Poly(lactic acid); Essential oil; Films; Nanofibrillated cellulose; pH indicator
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2022.05.116

Active and pH-sensitive films of poly(lactic acid) (PLA)/nanofibrillated cellulose (NFC) have been fabricated and tested. The PLA and PLA/NFC films with 1.5% NFC were prepared via solvent casting method, with different loadings of essential oil (EO), including thymol and curry, being added at 5, 10, and 15%. The fixed content of anthocyanin powder (1%) was incorporated into the films as a pH indicator. The active PLA and PLA/NFC films were characterised on their physical, mechanical, thermal, and biodegradation properties. The addition of NFC reduced the tensile strength but increased the flexibility of films due to the plasticizing effect of EOs. The PLA/EO and PLA/NFC/EO films containing curry demonstrated a slightly higher strength than the films with thymol. The flexibility of films was increased at higher loading of EO regardless of the types of EO. The thermal profile demonstrated that the neat PLA film had a higher maximum degradation temperature than the active PLA/EO and PLA/NFC/EO films. The active PLA/EO and PLA/NFC/EO films containing anthocyanin successfully changed its colour in pH 2.0 and 14.0. The PLA/NFC films with thymol and anthocyanin formulation could inhibit fungus growth better in the cherry tomato sample than the PLA/NFC films with curry and anthocyanin. •Addition of thymol EO improves the flexibility of PLA/EO and PLA/NFC/EO films than the curry EO•Addition of NFC increases the thermal stability of films, but no significant changes with the addition of EOs•Multifunction packaging particularly active and pH-sensitive films of PLA/NFC bionanocomposites has been developed•This active and pH-sensitive films can detect quality changes of food and prolong shelf-life of food