Red pomelo peel pectin based edible composite films: Effect of pectin incorporation on mechanical, structural, morphological and thermal properties of composite films

Red pomelo peel pectin, casein and egg albumin were mixed at various proportions to form edible composite films using casting method. The effect of addition of pectin at different concentration on the mechanical, structural, morphological and thermal properties were investigated. The composite films developed by mixing red pomelo peel pectin, casein and egg albumin at ratio of 50:50:0 (F4) and 50:25:25 (F7) possessed lower water vapour permeability and higher tensile strength in comparison to other films. The diffractograms obtained from XRD analysis revealed the amorphous structure of pectin film and pectin blended composite films. The FT-IR analysis revealed that with the addition of pectin, intermolecular interaction increased resulting in the compactness of film matrix. Pectin incorporated composite films were smooth in structure with no cracks and cavities indicating proper homogenization with no phase separation as well as indicated decrease in the degree of disorder in composite films. Thermal properties of composite films indicated that pectin incorporation into films resulted in increase in thermal stability of films.