Chitosan biofilm properties as affected by the addition of oregano essential oil

Abstract

In this work, effect of adding essential oil of oregano (OEO) into chitosan edible film was studied. Different amount of OEO, from 0.2 to 0.8%v/v was added to the film forming solution containing 0.4%w/v of chitosan. Control sample was produced without oil. Effect of growing oil content on film water sensibility was investigated. Pure chitosan film is hydrophilic and sensitive to water. It swells and partially dissolves in water. Addition of hydrophobic OEO lowered film water sensitivity, regarding film water content and swelling property. Film dissolution in water wasn't reduced, probably because OEO molecules diffused from chitosan film into water. Color change of chitosan film with addition of OEO was also investigated. Film greenness and lightness decreased until film yellowness and redness increased. Seen by naked eye, films became milky, opaque and whitish to yellowish.

Keywords

• packaging
• properties
• biopolymers
• chitosan
• oregano