Changes brought about in solid substrates after fermentations of mixtures of cereals and pulses with Rhizopus oryzae

Fermentations of Rhizopus oryzae using a mixture of soya grits and rye flakes resulted in increases in protein content of up to 36% over a 96‐h incubation period. Increases in oil and nucleic acid were also recorded. The increase in protein content was largely explained by a decrease in dry weight of the fermented material. Increasing aeration in petri dishes used for fermentation did not affect protein content or weight loss. pH changes in fermented substrates were related to the nature of the ingredients used. A marked reduction in pH occurred when cereals were fermented. Three different methods for assessment of biomass in solid substrates are compared.