Methods of incorporation of D-limonene microparticles in edible films

Abstract

In the present work, D-limonene was microencapsulated by ionic gelation using alginate and calcium ion and applied in the formulation of gelatin and chitosan biodegradable edible films. Three methods of incorporation of the microparticles were evaluated in the film-forming solution: magnetic stirring, high speed stirring (Ultra-turrax), and sonication. The morphology of the microparticles and films were evaluated by optical microscopy and scanning electron microscopy (SEM). The efficiency of encapsulation (EE), and mean diameter of the microparticles, and mechanical properties and water vapor permeability (WVP) of the films were also determined. The D-limonene microparticles showed a spherical shape with a mean diameter of 134.6 mm, and EE of 83.95 %. The incorporation of the microparticles increased tensile strength, Young’s modulus, and WVP, and it reduced the elongation at break of the films. However, among the incorporation methods there was no significant difference in the evaluated properties, suggesting that simple method such as magnetic stirring was sufficient to disperse the microparticles in the filmogenic solution.