Abstract
The brewing industry annually produces nearly 200 billion litres, generating more than 15 million tons of malt residue. Most of this residue is used to generate energy for the industries' operation. However, a still significant part, estimated at more than 1.5 million tons, coming mainly from small and medium breweries, does not have a good destination. Given this context, this research aimed to develop a bio compound to replace conventional wood agglomerates made from brewing malt residue with pre-gelatinised corn and PVA glue. Bio compound with brewer's residue was made by following steps: pre-gelatinised corn was initially driven by extrusion in an IMBRA RX50, single screw extruder (INBRAMAQ, Ribeirão Preto, SP). Soon after extrusion, extruded was ground in a hammer mill with a smaller than 0.7 mm particle size. The pre-gelatinised was mixed with the brewer's residue, PVA glue, and water in proportions established in the experimental design and pressed in a hydraulic press at 40 kg/cm2. Each sample was dried in an oven with air circulation at 70 °C for 24 hours. After the oven, the material was placed in a desiccator until the analysis. All treatments established in the experimental design were subjected to characterisation analyses: Mechanical resistance by Texture Analyzer TAXT2 Plus (Stable Micro Systems, England), density, moisture by AOAC methods, and Colour by Minolta Chroma Meter CR-400 colourimeter. With the analysis of the results, it was possible to identify that the material formed with the proportion 65:35 (residue / pre-gelatinised corn) plus 10 % of PVA presented better results in terms of mechanical resistance. The analysis of Colour and appearance of the material does not show significant variation in the results, and it was impossible to establish a better treatment for these characteristics. The data presented could conclude that the bio compound developed could be a good destination for this waste since it showed physical characteristics like conventional agglomerates, with the additional advantages of low cost and lower environmental impact due to no use of chemical components in its composition.
