Pelleting Wheat-Based Distiller's Dried Grains with Solubles: Quality Characteristics

Abstract

The rapid expansion of ethanol processing plants in Canada has resulted in increased production of wheat-based distillers dried grains with solubles (DDGS). The transportation of the granular DDGS is becoming expensive and flowability of the material might be restricted during unloading due to caking. These have necessitated the need to pellet the granular DDGS before transportation. The possibility of pelleting wheat-based DDGS was investigated by using two die sizes 6.4 (1/4) and 7.9 mm (5/16 in.) with steam addition and without steam addition. A 1.5 kW (2.0 hp) CPM (California Pellet Mill Co., Crawfordsville, IN) CL-5 laboratory pellet mill was used. Moisture content, bulk density, durability and throughput of the DDGS pellets were determined. Proximate analysis of the samples was done. The results show that the values of crude protein, neutral detergent fibre and acid detergent fibre ranged from 37.37% to 40.33%, 51.04% to 51.87%, and 15.78% to 22.93%, respectively. It was possible to pellet the wheat-based DDGS by using different die sizes, with steam addition and without steam addition. The bulk density of the DDGS pellets ranged from 436.8 to 528.9 kg/m3. The durability of the DDGS pellets ranged from 60.3% to 92.7% with a throughput range of 45.52 to 68.77 kg/h. The die size and steam addition had a significant effect on the bulk density and the durability of the DDGS pellets. Pelleting the DDGS with a die size of 1/4 in. and with steam addition produced the highest pellet bulk density and durability values compared to the other tests (5/16 in. die with or without steam addition)