Protein utilization during soybean tempe fermentation.
The aim was to identify to what extent proteins were utilized during the fermentation of bacteria-free tempe prepared with acidified soybean cotyledons and Rhizopus oligosporus NRRL 2710 at 30 degrees C. Dry matter declined continuously 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 initial dry cotyledons) at 72 h and representing approximately 70% and 80%, respectively, of the total dry matter loss. Protein oxidation (estimated from ammonia production) was 5 g at 28 h,10 g at 46 h, and 20 g/(kg of initial dry cotyledons) at 72 h. The total amount of soy protein hydrolyzed, including 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. Of this hydrolyzed protein, it is suggested that approximately 65% remained in the tempe as amino acids and peptides, 25% was assimilated into mold biomass, and 10% was oxidized.
Sparringa
R A
RA
Department of Food Science and Technology, The University of Reading, Reading, RG6 6AP, U.K.
Owens
J D
JD
D005285:Fermentation; D006801:Humans; D050356:Lipid Metabolism; D009584:Nitrogen / Q000378:metabolism; D012233:Rhizopus / Q000254:growth & development / Q000378:metabolism*; D030262:Soybean Proteins / Q000378:metabolism*; D013025:Glycine max / Q000378:metabolism* / Q000382:microbiology
D030262:Soybean Proteins; D009584:Nitrogen