Effects of Varying CDS levels and Drying and Cooling Temperatures on Flowability Properties of DDGS
Demand for alternative fuels and the need to reduce dependence on fossil fuels, have triggered the growth of corn-based ethanol production, and this is expected to rise in future years. Transportation of the co-product distillers’ dried grains with solubles (DDGS) from this industry occurs under various environmental conditions. This is often problematic, since caking between the particles can lead to flow problems. In this study we have prepared DDGS by combining condensed distillers’ solubles (CDS) with distillers’ wet grains (DWG) and then drying. We investigated the effects of CDS (10, 15, and 20% wb), drying temperature (100, 200, and 300°C), and cooling temperature (-12, 25 35°C) levels on the flowability of the resulting DDGS. Statistical analyses of the resulting data found significant differences among the cooling temperature levels for Angle of Repose, Total Flow and Flood indices, Dispersibility, water activity, and Protein Dispersibility Index. Additionally, significant interaction effects between CDS, drying temperature, and cooling temperature levels for Angle of Repose, Total Flow and Flood Indices, Dispersibility, and Protein Dispersibility Index were observed as well. Response surface regression on selected dimensionless flowability parameters was also applied. However, multivariate PLS regression yielded better results (R2 > 0.8) than response surface plots. Understanding the effects of drying and cooling temperatures as well as CDS levels can be used help to improve the industrial processing of DDGS and improve storage and transportation.
This is the post-print of an article that has been accepted for publication in Cereal Chemistry (forthcoming), doi:10.1094/CCHEM-04-12-0042-R.