Biodegradable antifungal films from nanocellulose-gellan gum incorporated with Anethum graveolens essential oil for bread packaging

Biodegradable material incorporated with antifungal essential oil has become an alternative food preservation approach to reduce plastic waste. Essential oils of Amomum testaceum, Anethum graveolens, Piper longum, Kaempferia galanga, and Zanthoxylum limonella were tested for their antifungal activity against Aspergillus niger. A. graveolens essential oil demonstrated the highest inhibition zone diameter of 43.51 mm against A. niger after seven days comparing to those obtained from other essential oils ranging from 10.02 mm to 26.13 mm. The volatile compounds of A. graveolens essential oil were identified with major compounds such as carvone, trans-dihydrocarvone, limonene, and α-acorenol. The pineapple nanocellulose-gellan gum (PNC-GG) films incorporated with A. graveolens oil were formulated and tested for its physical and chemical properties. Addition of A. graveolens essential oil in PNC-GG films improved mechanical strength and decreased flexibility while solubility, water vapour permeability, and thermal stability slightly changed. PNC-GG films incorporated with A. graveolens essential oil were also tested as bread packaging inhibiting A. niger. The results indicated that no visible mycelial growth of A. niger was detected during 3-week storage. Therefore, the PNC-GG films incorporated with A. graveolens essential oil were recommended as biodegradable packaging material against A. niger in bread also extending its shelf life.