Composition and nutritive value for rats of Aspergillus niger solid fermented barley

Abstract

Aspergillus niger fermented barley was produced by solid-state fermentation at laboratory scale. Its chemical composition was compared with unfermented barley. Fermented barley contained about 22% of crude protein and about 16% of true protein on a dry matter basis. Compared with barley, the amino acid profile of fermented barley was improved but the total amino acid analyzed accounted for only 72% of crude protein. The nutritive value of fermented barley was compared with casein, unfermented barley and soya-bean meal. Protein efficiency ratio and net protein ratio values represented about 62%, 84%, 76% and 91% of those observed for casein and original barley, respectively. Dry matter digestibility, metabolizable energy, true digestibility of nitrogen, biological value and net protein utilization of fermented barley were 83.5%, 14.7 MJ kg −1, 82.0%, 69.4% and 56.9% versus 80.7%, 14.7 MJ kg −1, 80.8%, 75.5% and 61.8% for original barley, respectively. Aspergillus niger fermented barley showed a reasonable potential as a new source of protein for simple-stomached animals but its non-α-amino N content must be reduced.