title: Physical, mechanical and barrier properties of corn starch films incorporated with plant essential oils.
abstract: Corn starch-based films are inherently brittle and lack the necessary mechanical integrity for conventional packaging. However, the incorporation of additives can potentially improve the mechanical properties and processability of starch films. In this work two essential oils, Zataria multiflora Boiss (ZEO) or Mentha pulegium (MEO) at three levels (1%, 2% and 3% (v/v)), were incorporated into starch films using a solution casting method to improve the mechanical and water vapor permeability (WVP) properties and to impart antimicrobial activity. Increasing the content of ZEO or MEO from 2% to 3% (v/v) increased values for elongation at break from 94.38% to 162.45% and from 53.34% to 107.71% respectively, but did not significantly change tensile strength values of the films. The WVP properties of the films decreased from 7.79 to 3.37 or 3.19 g mm m(-2) d(-1) kPa(-1) after 3% (v/v) ZEO or MEO incorporation respectively. The oxygen barrier properties were unaffected at the 1% and 2% (v/v) oil concentration used but oxygen transmission increased with 3% (v/v) for both formulations. The films' color became slightly yellow as the levels of ZEO or MEO were increased although transparency was maintained. Both films demonstrated antimicrobial activity with films containing ZEO more effective against Escherichia coli and Staphylococcus aureus than those containing MEO. These results suggest that ZEO and MEO have the potential to be directly incorporated into corn starch to prepare antimicrobial biodegradable films for various food packaging applications.
authors.affiliation: School of Packaging, Michigan State University, East Lansing, MI 48824, USA. ghasemlo@msu.edu
authors.forename: Mehran
authors.initials: M
authors.lastname: Ghasemlou
authors.forename: Nahal
authors.initials: N
authors.lastname: Aliheidari
authors.forename: Ronak
authors.initials: R
authors.lastname: Fahmi
authors.forename: Saeedeh
authors.initials: S
authors.lastname: Shojaee-Aliabadi
authors.forename: Behnam
authors.initials: B
authors.lastname: Keshavarz
authors.forename: Marlene J
authors.initials: MJ
authors.lastname: Cran
authors.forename: Ramin
authors.initials: R
authors.lastname: Khaksar
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology; D019453:Escherichia coli O157 / Q000187:drug effects; D018857:Food Packaging / Q000379:methods*; D055595:Mechanical Phenomena; D027541:Mentha / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry*; D055620:Optical Phenomena; D010100:Oxygen / Q000737:chemistry; D010539:Permeability; D055585:Physical Phenomena; D013211:Staphylococcus aureus / Q000187:drug effects; D013213:Starch / Q000737:chemistry*; D013499:Surface Properties; D014835:Volatilization; D014867:Water / Q000737:chemistry
chemical_list: D000890:Anti-Infective Agents; D009822:Oils, Volatile; D014867:Water; D013213:Starch; D010100:Oxygen
keywords: Antimicrobial properties; Atomic-force microscopy; Corn starch; Essential oil; Physical properties