Physical, barrier, mechanical and microstructural properties of Aloe vera-gelatin-glycerol edible films incorporated with Pimenta dioica L. Merrill essential oil

Abstract

Physical, barrier, mechanical and microstructural properties of an edible film based on Aloe vera, gelatin-glycerol with different concentrations of the essential oil of a pepper (Pimenta dioica L. Merrill) at 0, 0.5, 1.0, and 1.5% w/w were investigated. The optical properties showed low brightness and ΔE of 59.6. In terms of water vapor permeability, the values ranged from 2.54 ×10-9 ± 0.09 to 4.49 ×10-9 ± 0.3 (g m/Pa s m2), due to the effect of decreased polarity in the structural matrix. In the case of the mechanical properties, an increase in the oil concentration significantly reduced the tensile strength, making the material more flexible (% E = 72 to 122), possibly due to the rearrangement of and the interaction between polysaccharides, proteins and plasticizers in the matrix. This behavior was also observed in the microstructural studies: the increased concentration of oil increased the roughness of the film (Ra = 0.222 to 2.12 mV). The results show that addition of Pimenta dioica oil to the film results in a film with increased WVP and resistant film qualities that favor the material for use in high-moisture food coating applications.