Gluten-Based Bioplastics for a Controlled-Release of Active Agents

Abstract

In recent years there has been a great interest to utilize renewable biomass in the manufacture of high-quality, cost-competitive and biodegradable consumer goods as a means of reducing the dependence and consumption of petrochemical feedstock and of diminishing environmental pollution. This work focuses on the development of new bioplastic materials based on wheat gluten proteins containing an antimicrobial agent (i.e. lisozyme, formic acid, sorbic acid and/or essential oil compounds) by means of direct mixing of the proteins with a plasticizer, glycerol and active agent, and, eventually, a thermal and moulding process which shapes the materials and gives them suitable mechanical properties to be used as substitutive materials of synthetic polymers in certain applications. These mechanical properties have been evaluated by Dynamic Mechanical Thermal Analysis (DMTA) on both intermediate process material and on the final bioplastics. Diffusion and water absorption tests were carried out in order to study the influence of the above-mentioned treatments on the physico-chemical characteristics, controlled-release properties and rheological behaviour of these bioplastic samples. Protein-based bioplastics containing biocide have demonstrated antimicrobial activity and a suitable biocide release, which depend on the formulation and thermo-mechanical processing.