Corn Distillers Wet Grains

The production of corn‐based ethanol in the United States is dramatically increasing, and consequently, so is the quantity of generated coproducts, all of which are currently fed to livestock. Distillers Wet Grain (DWG) is one of these coproduct feeds. Many studies have investigated the nutritional properties of DWG and the response of livestock (primarily beef and dairy) to inclusion of these ingredients in their diets. To date, physical properties have been largely ignored, but they are needed for the design of storage facilities and equipment. The objective of this research was to quantify physical and chemical property values for typical DWG streams. Using standard laboratory methods, several properties were determined, including moisture content, water activity, thermal properties (conductivity, resistivity, and diffusivity), bulk density, color, pH, protein, fiber, fat, and ash. The DWG samples in this study were golden‐brown in color. They had moisture contents ranging between 53 and 54% (w.b. – wet basis), and were thus highly susceptible to rapid spoilage. They had high bulk density (approximately 858 to 975 kg/m3) and had a low propensity for storing and transmitting heat, due to the high water content. Nutritional content of the DWG studied was similar to that reported by other investigators. Color changes over time were also monitored, and it appeared that the Hunter L value can be correlated with total fungi (r = 0.60), yeasts and molds (r = 0.61), and aerobic heterotrophs (r = 0.60) colonizing the DWG. The data generated during this study will help fill the current void and be useful to both the ethanol and livestock industries. Further study is warranted in order to capture more fully the differences in physical, chemical, and microbial properties among ethanol production plants and over time. Additionally, rapid sensing techniques for the determination of these parameters and the quantification of spoilage criteria should be