Fractionation of Distillers Dried Grains with Solubles (DDGS) by Combination of Sieving and Aspiration

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Cheng, Ming-Hsun
Riess, Samantha
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The high protein and oil contents of Distiller’s dried grains with solubles (DDGS) can be obtained by separating raw DDGS into different particle sizes fractions. The separation processes included four sieving and aspiration procedures. Sieving was able to produce fractions with different compositions. As the particle size decreased, the protein and oil content of DDGS increased. For aspiration, that separated DDGS into different fractions depending upon different gravity profiles of protein, oil and fiber basically. The terminal velocity of airflow was determined for each sieving fraction. Large and heavy fractions consisted of mainly protein and oil; light fractions were enriched in fibers. The higher airflow velocity increased the mass of light fraction, while the higher protein content can be obtained in heavy fraction. As the different conditions of treatment are used that caused the shifting on DDGS nutrients composition. According to the gravity profile of each nutrient, the different combinations of variables play a critical role for improving the efficiency of DDGS fractionation. The proper combination and interaction of variables for protein and oil separation are higher flowrate, smaller particle sizes, and the fraction with higher density, and the best efficiency for protein and oil separation reaches about 29.7 and 68.15% respectively; for fiber, mild flowrate, larger particle sizes and the fraction with lower density are able to obtained higher fiber content approximately 7%.The combination of primary sieving and specific airflow velocity application in aspiration process was capable of improving the results of separation of DDGS. This could raise the value of DDGS and achieve the concept of sustainable utilization of bioresources.

Wed Jan 01 00:00:00 UTC 2014