Development and characterization of Caesalpinia pulcherrima seed gum-based films to determine their applicability in food packaging

Investigation of potential biopolymers for developing edible films as alternatives for plastic packaging is a recent trend. Among the biopolymers used in edible film making, galactomannan is a good film-forming agent. Caesalpinia pulcherrima seed gum is a rich source of galactomannan and could be used as an edible film making material. The main objective of this study was to identify the ability of Caesalpinia pulcherrima seed gum in making a food packaging film and assessing its performance. In this study, the gum was extracted from Caesalpinia pulcherrima seeds and dissolved in distilled water along with the plasticizer glycerol. In preparing film-forming solutions, a previously selected range of glycerol concentrations (0.0, 0.5, 1.0 and 1.5%) was used. After casting and drying, the resultant films were analyzed for their physical and mechanical properties. In the present study, the film prior to incorporating glycerol was brittle, less flexible and had a strong film matrix. With the increase of glycerol content, the film became more flexible, sticky and weak. Further, the physical properties namely thickness, moisture content, swelling index, water solubility of Caesalpinia pulcherrima seed gum-based films were increased from 0.039 ± 0.001 to 0.076 ± 0.001 mm, from 62.92 ± 0.51 to 69.40 ± 0.15%, from 5.39 ± 0.17 to 8.45 ± 0.17, from 55.69 ± 0.51 to 66.66 ± 0.45%, respectively, with the increase of glycerol content from 0.0 to 1.5%. Concerning the mechanical properties, the tensile strength and Young’s module were decreased from 10.90 ± 0.08 to 2.11 ± 0.05 MPa and from 48.46 ± 0.24 to 3.47 ± 0.09 MPa, respectively, and the elongation was increased from 22.50 ± 0.05 to 60.84 ± 0.04% with increasing the glycerol content from 0.0 to 1.5%. Due to its physical and mechanical properties, Caesalpinia pulcherrima seed gum is a potential source for edible packaging film manufacture.