Changes in the Nutrient Composition of Brewery Spent Grain Subjected to Solid State Natural Fermentation

Abstract

Spent sorghum grains were fermented naturally for a period of five weeks at room temperature with a view to determining the effects of fermentation on their nutrient compositions. The chemical analyses of the samples were carried out according to AOAC standard methods (AOAC, 1980). Fermentation brought about an increase in the Crude Protein, Total Lipid and Nitrogen Free Extract contents by 34.80%, 41.44% and 47.81% respectively. The Crude Fibre content of the spent grain dropped to 10.54% while Calcium and phosphorous values were found to increase. A fermentation period of three weeks was observed to be optimum for the significant (P<0.05) enhancement of the protein content of the grains. Amino acids like lysine, leucine and glutamic acid were found to be slightly boosted while histidine, arginine, aspartic acid, threonine, serine, proline, glycine, alanine, cystine, valine, methionine, isoleucine, tyrosine and phenylalanine were found to be depressed.

Key word: Spent sorghum grains, fermentation, Nutrient composition, Brewery spent grain