Lactic Acid Fermentation of Carrot and Red Beet Juices by Probiotic Bacteria

Carrots and red beet were evaluated as a potential substrate for the production of lactic acid fermented juices by Lactobacillus acidophilus and Bifidobacterium sp. Both strains were found capable to grow on the vegetable juices, but some differences between the dynamics of the processes, dependent not only by the culture but by the sort of the raw material, had as consequence the production of the final products with different stability degrees. The pH value of the carrot juices was decreased from an initial value by 6.45 to below 4.3 after 48 hours of lactic acid fermentation with Bifidobacterium sp., respectively to 3.84 after 24hours when Lactobacillus acidophilus was inoculated. The last strain has produced a significant increase of the titrable acidity, the fermented carrot juices containing 0.7% acids (expressed as lactic acid). In the case of the fermentation of the red beet juices it is also recommended the strain of Lactobacillus acidophilus, because the pH value decrease with 2 units in 24 hours. The best acidification kinetic parameters were determined in the case of the carrot juices fermented by Lactobacillus acidophilus. In the same process the value of the R squared coefficient showed a strong correlation between the biomass amount and the production of lactic acid.