Protein utilization during soybean tempe fermentation

The aim was to identify to what extent proteins were utilized during the fe rmentation of bacteria-free tempe prepared with acidified soybean cotyledon s and Rhizopus oligosporus NRRL 2710 at 30 degrees C. Dry matter declined c ontinuously during the fermentation to 980 g/(kg of initial dry cotyledons) at 28 h, 910 g at 46 h (when the tempe was judged mature), and 835 g at 72 h. The decrease in dry matter was due mainly to reduction in crude lipid, amounting to 65 g/(kg of initial dry cotyledons) at 46 h and 135 g/(kg of i nitial dry cotyledons) at 72 h and representing approximately 70% and 80%, respectively, of the total dry matter loss. Protein oxidation (estimated fr om ammonia production) was 5 g at 28 h, 10 g at 46 h, and 20 g/(kg of initi al dry cotyledons) at 72 h. The total amount of soy protein hydrolyzed, inc luding that incorporated into mold biomass, was estimated to be 80 g/(kg of initial dry cotyledons) at 28 h incubation, 95 g at 46 h, and 100 g at 72 h. The hydrolyzed protein at 46 h represented 25% of the initial protein. O f this hydrolyzed protein, it is suggested that approximately 65% remained in the tempe as amino acids and peptides, 25% was assimilated into mold bio mass, and 10% was oxidized.