Evaluation of antimicrobial activity of Poly Lactic Acid (PLA) films containing cellulose nanoparticle and Bunium persicum and Mentha pepperita essential oils (EOs)

Abstract

BACKGROUND: Packaging is one of the important aspect of food quality and safety. Unfortunately, most of food packaging materials are from oil resources that are limited resources and undegradable. OBJECTIVES: The aim of this study was reaching an environmentally friendly packaging with enhancement safety of food. METHODS: After obtaining Bunium persicum (BP) and Mentha pepperita (MP) essential oils (EOs) by steam distillation method, their chemical compositions were determined using GC-MS analysis. PLA films were prepared using solvent casting technique containing different concentrations of BP (0, 0.5 and1%v/v), MP (0, 0.5 and1%v/v) EOs and cellulose nanoparticle (CN) (0 and 1% w/v) and their antimicrobial effects against gram positive bacteria (Staphylococcus aureus ATCC 65138, Bacillus cereus ATCC 11778) and Gram negative bacteria (Vibrio parahaemolyticus ATCC 43996, Escherichia coli O157:H7 and Salmonella typhymurium ATCC 14028) were assessed by disk diffusion method. RESULTS: Major compounds of BP EO were Propanal 2-methyl-3-phenyl (34.08%), Cymene (18.23%) and Myrtenal (12.37%) and for MP EO were p-Menthan-3-ol (44.59%) and p-Menthan-3-onetrans (12.14%). The results of present study indicated that pure PLA film or PLA films containing CN showed no antimicrobial activity against any of the five tested bacteria but films containing EOs had significant antimicrobial activity and BP EO was more effective than MP EO and their combination (p<0.05). Besides, the inhibitory effect of films were concentration-dependent. In addition results of current study revealed, gram-positive bacteria were more sensitive than gram negative bacteria to PLA films containing EOs. CONCLUSIONS: The results of this study indicated that PLA films containing MP and BP EOs may be useful for packaging of foods in order to increase their shelf life and safety.