Nutrition evaluation and mutagenicity testing of freeze-dried distiller's grains with solubles.

Distiller's grains with solubles (DGS) was obtained from a commercial fermentation of 90% corn and 10% wheat for ethanol production. The DGS was freeze-dried and proximate analysis resulted in 17.6% protein, 5.5% fat, 3.0% ash, 17.3% moisture, 21.6% neutral detergent fiber, and 35% carbohydrate by difference. Fatty acid analysis and amino acid analysis were similar to those of corn. Tryptophan was the limiting amino acid with a chemical score of 47. Protein Efficiency Ratio (PER) was 1.49. Mutagenicity testing of lipid and aqueous extracts of DGS in the Ames Salmonella mammalian microsome assay were negative.