Dairy foods: production ofγ-aminobutyric acid by cheese starters during cheese repening

摘要

Nine mixed-strain starters were examined for their abilities to produceγ-aminobutyric acid. Six commer- cial starters were found to produceγ-aminobutyric acid in a skim milk culture. The bacterium that producedγ-aminobutyric acid was isolated form the mixed-strain starters, identified as citrate-utilizing Lactococcus lactis ssp. Lactis(formerly L.lactis ssp. Lactis biovar diacetylactis)and designated as strain 01-7. A cell extract showed glutamate decraboxylase activity, for which the optimum pH was 4.7. In pH- controlled cultivation, γ-aminobutyric acid was gener- ated at pH 5.0 but not above pH 5.5.