Biopolymer based on brewing waste and extruded maize: characterization and application

The brewing industry produces more than 100 billion litres a year worldwide and consequently more than 20 million ton of solid waste. This waste is mostly destined for animal feed; however, it ends up being a form of disposal of low added value. On the other hand, furniture and decorations items of a bar can use such waste for its confection, which adds value to the waste and mentions the own beer. This work aimed to develop and characterize a biopolymer obtained from the brewing residue (milled malt after mashing process) and extruded maize to be used as a raw material for furniture and in architectural wall coverings. The proportions of components, time and temperature of the drying process and malt milling were variated in nine treatments. The wood chipboard was used as a control as well. Tensile strength, young's modulus, and elongation at break were analysed, water absorption index (WAI) and water solubility index (WSI) were determined, and the colour was evaluated. After the material was characterised, the better mixtures were applied to make a board used in furniture and wall coverings. The sensorial analysis (visual) was made with 117 non trained panellists to evaluate the new material's acceptance to replace wood-based boards. The main results showed that lower drying temperature, as well as the higher amount of extruded maize, could increase the resistance of the material. There is no significant evidence that particle size affects the material's resistance; on the other hand, it was essential to increase the material acceptability, the smaller was particle size, the better was the acceptance as a substitute of wood-based boards. It was possible to conclude that the material has high acceptance and adequate physical properties to be used in some furniture and covering walls. It is an excellent alternative to increase the value of this industrial waste.