Skip to main content
Article
Predicting Stability of Distiller’s Wet Grains (DWG) with Color Analysis
Food and Bioprocess Technology (2010)
  • R. M. Lehman, United States Department of Agriculture
  • Kurt A. Rosentrater, United States Department of Agriculture
Abstract

Distiller’s wet grain (DWG) is one of the coproducts from the fuel ethanol industry. Although many studies have investigated the nutritional properties of DWG, little work has investigated the storability and shelf life for these feed products or how to measure these quantities. The objectives of this research were to measure the development of microorganisms and their respiration over time in freshly produced DWG and to determine if there was a quantitative relationship between these microbiological parameters and a more easily measured physical property, DWG color. The numbers of aerobic heterotrophic bacteria, molds and yeasts, and carbon dioxide generated by microbial respiration were measured at t = 0, 1, 2, 4, and 7 days as were Hunter color (L, a, b) values. All of the microbial parameters increased significantly over time (p < 0.05). Hunter L and a values appeared to change over time as well, but these differences became significant only at t = 7 days; at this time period, Hunter b changed significantly also. Hunter a and b values were negatively correlated with aerobic heterotroph numbers (r = −0.74 for Hunter a; r = −0.77 for Hunter b), yeast and mold counts (r = −0.78 for Hunter a; r = −0.81 for Hunter b), and CO2 production (r = −0.89 for Hunter a; r = −0.87 for Hunter b). Hunter L values had moderate positive correlations with the microbial parameters (r values ranged from 0.42 to 0.57). Using Hunter a and b color parameters as predictor variables, multiple linear and nonlinear regressions produced R 2 values of 0.751, 0.665, and 0.816 for aerobic heterotrophs, molds and yeasts, and CO2 generation, respectively. Additional research should quantify spoilage criteria, the relationship to palatability, and determine how best to use color changes as indicators of each.

Publication Date
March, 2010
Publisher Statement
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Citation Information
R. M. Lehman and Kurt A. Rosentrater. "Predicting Stability of Distiller’s Wet Grains (DWG) with Color Analysis" Food and Bioprocess Technology Vol. 3 Iss. 2 (2010)
Available at: http://works.bepress.com/kurt_rosentrater/151/