Factors influencing the production of acetoin and di acetyl by lactic acid bacteria in skim milk
Abo Elnaga, I.G.; Hegazi, F.Z.
Nahrung 25(9): 883-890
Nine strains of starter cultures belonging to the genera Streptococcus, Leuconostoc and Lactobacillus were studied for the effect of pyruvate concentration, incubation period and the associative growth on the production of acetoin and diacetyl in skim milk. The absolute amount of acetoin and diacetyl and the amount per micromole pyruvate increased with increasing the concentration of pyruvate. At the low concentration of pyruvate the maximum amount of these neutral carbonyl compounds was first reached after 34 days, whereas at the high concentration it was readily achieved after 6 days and then decreased. Production of acetoin and diacetyl by mixed-species cultures from added citrate was increased or markedly decreased compared to the single-species culture.