Physical and Barrier Properties of Apple Pectin/Cassava Starch Composite Films Incorporating L aurus nobilis L. Oil and Oleic Acid

Abstract

Edible composite films were prepared from apple pectin/cassava starch, 1.5% (w/v), containing different concentrations of Laurus nobilis L. oil and oleic acid (0.5, 1.0 and 1.5% v/w). The effects of L. nobilis L. oil on the physical properties of the resulted composite films were investigated. Samples with 1.5% (v/w) L. nobilis L. oil showed increased thickness (43.55–51.73 μm) and improved opacity; their barrier properties to UV radiation in the range of 200–280 nm significantly (P < 0.05) increased compared with that of the control film. The water vapor permeability of the films was reduced to 1.56 (g·mm/m2·day ·Pa) by adding more oil. The effect of L. nobilis L. oil on the oxygen permeability was lower (0.31 cc/m2/day). The measurement of color values showed that by increasing the oil content in polymer matrix, the L* values (lightness) and whiteness index decreased (P < 0.05), whereas the b* values (yellowness), a* values (greenness), yellowness index and total color difference (ΔE) of the films increased (P < 0.05). The surface microstructure of the matrix films was analyzed using atomic force microscopy, and the surface structures of the films were determined using scanning electron microscopy. The mechanical properties were also affected by the addition of L. nobilis L. oil; the tensile strength was diminished, and elongation at breaking (E) increased considerably. Incorporating L. nobilis L. oil provides a novel way to enhance the physical and barrier properties of composite films. Practical Applications Research studies on edible films have received considerable attention in the recent years because of their capability to improve global food quality with all indications that interest will continue. Edible composite films were prepared from apple pectin/cassava starch containing different concentrations of Laurus nobilis L. oil and oleic acid. Edible film materials have been developed mainly because of their advantages, such as they are being used as edible packaging materials over synthetic films. The functional properties of edible films are greatly influenced by parameters such as formulation from polysaccharide, which have been suggested as a means of food protection, and preservation could contribute to the reduction of environmental pollution, film forming technology, solvent characteristics and additives.