CONTROL OF AMMONIA FORMATION DURING BACILLUS-SUBTILIS FERMENTATION OFLEGUMES

The control of ammonia formation during the Bacillus subtilis fermenta tion of autoclaved, roasted soybean cotyledons (Glycine mar) and of au toclaved African locust bean cotyledons (Parkia spp.) was investigated . Addition of NaCl, 1.5 mol (kg wet cotyledons)(-1), part way through the fermentation inhibited ammonia formation and softening of the coty ledons. Addition of glycerol, 1.7 mol (kg wet cotyledons)(-1) part way through the fermentation inhibited alkalinisation and ammonia formati on while allowing enzymic activity and softening of the cotyledons to continue. Restriction of the oxygen supply by incubating the cotyledon s in a sealed container also prevented excessive ammonia production an d increase in pH value. Fermentations conducted in sealed containers w ith an air to cotyledons ratio of approximately 130-175 ml air (g wet cotyledons)(-1) supported good microbial growth and proteolysis withou t the formation of detectable ammonia aroma.