Malic Acid as a Source of Carbon Dioxide in Cucumber Juice Fermentations

Abstract
The degradation of malic acid to lactic acid and CO2 during fermentation of cucumber juice was investigated. This malolactic reaction was the major source of CO2 when cucumber juice was fermented by Lactobacillus plantarum. It may also be an important CO2 source in controlled cucumber fermentations. In addition to CO2 production, the degradation of malate served to buffer the fermentation and increase sugar utilization. The pH after 7 days’fermentation was 2.8 when 13 mM malic acid was present in the juice and 4.1 with 135 mM malic acid. In the same fermentations, 52% of the sugars were degraded with the low malic acid concentration while complete sugar utilization was observed with the highest malic acid level.