Laboratory-scale fractionation of distillers dried grains with solubles (DDGS)

Abstract

<abstract> <bold>Abstract.</bold> The objective of this project was to separate distillers dried grains with solubles (DDGS) into high protein and high fiber fractions, in order to improve value and utility as a livestock feed. This project used a laboratory-scale cylindrical blower (Iowa blower) and a laboratory-scale gravity table (Whippet V-80 separator, Sutton, Steele & Steele, Inc.). The raw DDGS was sieved into multiple streams using 10 mesh, 20 mesh and 40 mesh screens. The 10-20 mesh fraction and 20-40 mesh fraction were then run on the blower and the separator separately, using the same settings for air velocity in the range of 0.32 m/sec to 3.06 m/sec. A high protein fraction was achieved (37.13% db) for the 10-20 mesh fraction with an air velocity of 2.42 m/sec by the blower. For the separator, using the same settings for airflow speed, the rate of eccentric shaft vibration, feedstock loading rate, side and end slopes, a high protein fraction was achieved (39.24% db) for the 10-20 mesh fraction with a range of the rate of eccentric shaft vibration from 350 rotation per minute to 500 rotation per minute. Another high protein fraction was also achieved (40.61% db) for the 20-40 mesh fraction with the same range of eccentric shaft vibration (350-500 rpm). As a result, good protein separation could be achieved by operating either the blower or the gravity table, although further study is required to optimize the separation efficiency.