The ability of diacetyl-producing lactic acid bacteria of the genus Lactococcus to release #alpha#-acetolactic acid into the medium

摘要

Two approaches to determination of #alpha#-acetolactate in the culture medium of lactic acid bacteria (by measuring the contents of acetoin and diacetyl) are discussed. The most widely used colorimetric method (determination of acetoin) cannot measure low concentrations of #alpha#-acetolactate (less than 0.6 mM). The use of an additional method (determination of diacetyl) extended the range of #alpha#-acetolactate concentrations detected. All 11 strains of Lactococcus lactis ssp. lactis biovar, diacetylactis studied were shown to accumulate 0.1-1.5 mM #alpha#-acetolactate in the medium, depending on the culture type and growth conditions. These data suggest that the most probable pathway of diacetyl formation is associated with nonenzymatic oxidative decarboxylation of #alpha#-acetolactate.