Laboratory-Scale Fractionation of Distillers Dried Grains with Solubles (DDGS)

Abstract

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.