Barrier properties, mechanical properties and antimicrobial activity of hydroxypropyl methylcellulose-based nanocomposite films incorporated with Thai essential oils

Hydroxypropyl methylcellulose (HPMC) is a promising hydrocolloid for use as a biopolymer film. Organically modified clay Cloisite 30B and beeswax were combined in the HPMC film to improve barrier and mechanical properties of HPMC films. However, HPMC-based nanocomposite film does not show any antimicrobial activity, which would enhance the film properties as an active package. Thus, the objective of this study was to determine the effect of Thai essential oils (EOs) on HPMC-based nanocomposite films. Three Thai EOs were selected-ginger (G), fingerroot (F) and plai (P). The addition of P or F increased the HPMC-based nanocomposite film oxygen permeability, but the addition of G did not. Incorporation of P in HPMC-based nanocomposite film increased the water vapor permeability of the films. As expected, EOs affected the total film color. Decreases in the elastic modulus and tensile strength accompanied with an increase in elongation were observed in film incorporated with G and F. HPMC-based nanocomposite films incorporated with F showed antimicrobial activity against Staphylococcus aureus and Escherichia coli using agar disc-diffusion assay. Therefore, HPMC-based nanocomposite films incorporated with EO might be suitable to apply as an active packaging material or as an active coating on agricultural produce such as fresh fruits to maintain their quality and extend their shelf life. (C) 2016 Elsevier Ltd. All rights reserved.