Development and characterization of biopolymers films mechanically reinforced with garlic skin waste for fabrication of compostable dishes

The pollution caused by use of petroleum-derivate plastic materials is a major environmental problem. This has encouraged researchers to develop new compostable and environmental-friendly materials based on biopolymers and agro-industrial residues. The aim of this work was to study the addition of garlic skin (GS) particles and the changes in physicochemical, mechanical, and microstructural properties of films formulated with potato starch and gellan gum as well as the creation of an environmentally friendly dish. Different concentrations (1, 2 and 3% w/v) and sizes (1410-213 μm, 212-39 μm and 38-1 μm) of GS particles were used for the mechanical reinforcement of the films and as independent variables of the experimental design. Different response variables (phenolic content, color difference, thickness, film transparency, stress, strain, Young's modulus, water solubility, water adsorption capacity, fractal dimension and entropy of the images) were evaluated to select the optimal point using response surface methodology (RSM). Microscopy techniques and texture image analysis were used to explain the effect of adding GS particles to the microstructure and mechanical reinforcement of the films. Moreover, thermogravimetric analysis (TGA), principal component analysis (PCA) and RSM were used to select the best film for making a compostable dish using a low-cost molding process at laboratory level. A novelty of this study was proposing an alternative use of GS waste in a film with biopolymers, integrating different analytical tools to facilitate the selection of the suitable formulations to create compostable dishes in 60 days, which goes beyond the traditional studies of coatings and polymeric films reported.