Journal of Food Science and Technology. 41, 469-474 (1994)

【Objective】

Organic acids which microorganisms produce play an important role to add flavor and acidity to fermented foods. However, the degree of acidity and quality varies based on each organic acid. When the balance between the acidity and quality of organic acids is improper, the taste becomes bad. There were not many studies about fumarase, one of the lactic acid bacteria which transforms fumaric acid to L-malate. In this study, we examined the cultural conditions which affect to the fumarate metabolism by 3 strains of Lactobacillus delbrueckii.

【Methods】

We determined the quantity of organic acids in the culture fluid. We filtrated bacterial bodies and measure the filtrate with high-performance liquid chromatography. The degree of bacterial growth was evaluated by optical density with 660 nm.

【Results】

Bacterial growth was promoted by applying fumaric acid to mediums based on the examination about medium compositions. We also examined the effect of metal-ion to the fumarate metabolic potential. The fumarate metabolic potential was enhanced in the culture added Mg2+, but it was suppressed in the culture added Cu2+. The transformation from fumaric acid to L-malate among these 3 strains associated with their growth and its maturity rate did not change either in static culture or shaking culture.