A New Process For Removing Fiber From Distillers Dried Grains With Solubles

Abstract

A new process was developed to separate fiber from distillers dried grains with solubles (DDGS) in a dry grind corn process. Separation of fiber from DDGS would provide two valuable coproducts: 1) DDGS with reduced fiber, increased fat and increased protein contents and 2) fiber. The process, called Elusieve process, used two separation methods, sieving and elutriation, to separate the fiber. Material carried by air to the top of the elutriation column was called the “lighter fraction” and material that settled to the bottom of the column was called the “heavier fraction”. We evaluated the compositions of fractions produced from sieving and elutriation. Two commercial samples of DDGS were obtained from two dry grind corn plants. Sieving over four screens (869, 582, 447 and 234 µm openings) created five size categories. The two smallest size categories contained > 40% (w/w) of the original DDGS and had reduced fiber and increased protein and fat contents relative to the original DDGS. Elutriation of the remaining three size categories increased protein and fat contents and reduced fiber contents in the heavier fractions. Elutriation at air velocities between 1.59 and 5.24 m/s increased the protein content of the heavier fraction by 13 to 41% and increased the fat content of the heavier fraction by 4 to 127% compared to the bulk fractions of each size category. This process was effective in separating fiber from both DDGS samples evaluated. Elusieve process does not require changes in the existing dry grind process and can be implemented at the end of the dry grind process.