Preparation and preliminary characterization of semi refined kappa carrageenan-based edible film incorporated with cinnamon essential oil

Abstract

Edibility and biodegradability are the most beneficial properties of edible films and coatings. Carrageenans are natural, water-soluble hydrocolloid composed of a linear chain of sulphated galactans and have high potential of film-forming material. Essential oils have attracted increasing attention in food additive industry since they possess well documented insecticidal, antimicrobial, and antioxidant activities. Cinnamon essential oil, a GRAS material, is amongst the most active essential oils, because of the antimicrobial-antioxidant potential. To the best of our knowledge, there are few report data on the characteristics of carrageenan-essential oil composite films. Therefore, this study aimed at developing semi-refined-kappa-carrageenan based edible films and carrageenan-films containing cinnamon essential oil. This study was divided into two stages. The effect of sorbitol plasticizer’s concentration (0.5%, 1.0%, 1.5 % v/v) on the mechanical and barrier properties of the semi refined kappa carrageenan-based edible film (2% b/v) were investigated at the first stage, and the effect of cinnamon essential oil’s concentration (0.5%, 0.75%, 1.0 % v/v) on the mechanical and barrier properties of the films were evaluated at the second one. Increasing sorbitol plasticizer concentration levels in film samples enhanced the thickness and % elongation at break (EB). In contrast, a decrease of tensile strength (TS) values and water vapor transmission rate (WVTR) were observed when the concentration levels of sorbitol plasticizer increased. Semi-refined kappa-carrageenan (2% b/v) produced in the first stage of the study were observed in film with 1% (v/v) addition of sorbitol plasticizer was chosen from the first stage. Furthermore, the incorporation of cinnamon essential oil 1% (v/v) was the recommended carrageenan composite edible film for the second stage of the study, suggesting the further application of this edible film for food application.