Fermentation and Growth of Plant Origin Lactic Acid Bacteria in Human Diet Model Medium

Abstract

Nine strains of Lactobacilli which were isolated from rice and processed rice products were tested for fermentation, survival of an artificial digestive juice and growth in medium of human diet model. They were compared with Lactobacillus acidophilus and L. gasseri which were used for fermented milk preparation or isolated from feces and intestines. Tested Lactobacilli were six strains of L. casei subsp. casei and three strains of L. plantarum. In most of plant material, plant origin lactic acid bacteria showed increase in the cell number and its fermented products were lowered under pH 5. In a stomach model test, the viable cell count maintained its initial level at pH 3 except L. acidophilus L-54. However the viable cell count decreased in many strains at pH 2.5. In a intestine model test, L. casei subsp casei, L. plantarum and L. acidophilus 1132 showed tolerance or growth under the condition of 0.2-0.4% bile powder, but the number of viable cell was smaller than the condition without bile. To compare growth of Lactobacilli on human diet, Japanese and American diet model medium containing 0.4% bile powder were prepared. L. casei subsp. casei and L. plantarum grew in both medium and the number of cell increased by passage in the medium. These results showed plant origin lactic acid bacteria has ability of probiotics.