Factors Affecting Oil Analysis of DDGS as Compared with Ground Corn

Authors: Liu, Keshun

Submitted to: American Oil Chemists' Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2009
Publication Date: 5/3/2009
Citation: Liu, K. 2009. Factors Affecting Oil Analysis of DDGS as Compared with Ground Corn. American Oil Chemists' Society Annual Meeting and Expo, Orlando, FL, May 3-6.

Interpretive Summary:

Technical Abstract: There are a few official methods for measuring oil/fat content in grains and feed. Yet guidelines on which method to be used for dried distiller grains with solubles (DDGS) are yet to be fully developed. In this study, a rapid determination of oil/fat utilizing high temperature solvent extraction (AOCS Approved Procedure Am 5-04) was used for measuring oil in ground corn and resulting DDGS. Factors, including sample type (ground corn and DDGS), sample variety (from ethanol plant 1, 2 and 3), sample particle size (original matrix, <25, and <35 U.S. standard mesh), solvent type (petroleum ether and hexane), extraction time (30 and 60 min), and drying time after extraction (30 and 60 min), were investigated by a complete factorial design. When measuring corn, only sample variety and extraction time had significant effect (p < 0.05) on oil values measured, but for DDGS, besides the two factors, sample particle size, solvent type and drying time also had significant effects. Among them, particle size affected most. On average, the measured oil content in DDGS ranged from 11.11% (original matrix), to 12.12% (< 25 mesh) and to 12.55% (< 35 mesh). In measuring oil in DDGS, particle size reduction, 60 min extraction and 60 min drying are recommended. Although petroleum ether gave a significantly higher value than hexane, the difference was relatively small.