Acidogenic and proteolytic activity of lactococci and streptococci in UF milk
1998
Radulovic, Z.T. (Poljoprivredni fakultet, Beograd - Zemun (Yugoslavia)) | Obradovic, D.B. | Fira, Dj.
The buffer capacity of milk equivalent (CF=1) and retentates (CF=3 and CF=4) were studied. Furthermore, the influence of milk equivalent and these retentates on the growth and activity of four strains of milk streptococci and lactococci: Streptococcus salivarius ssp. thermophilus 80, Streptococcus salivarius ssp. thermophilus S1, Lactococcus lactis ssp. lactis 763 and Lactococcus lactis ssp. lactis biovar. diacetylactis 2100 have been tested. The growth and production of lactic acid of the tested strains in UF milk have been observed during eight hours of fermentation. All strains most easily lowered pH value in milk equivalent and the decrease of pH value becomes slower with the decrease of concentration rate of retentate. With the increase of concentration rate of retentate, the growth of tested strains was more intensive and the logarithmic growth phase was prolonged. Proteolytic activity of these strains were examined by determination of tyrosine value and electrophoretic detection prt+ strains which were capable to hydrolize beta-casein. Better proteolytic activity was detected in lactococci than in streptococci.
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