Utilization of Lactobacillus amylovorus as an Alternative Microorganism for Saccharifying Boiled Rice

The growth condition of Lactobacillus amylovorus strain JCM 10628, an amylolytic lactic acid bacterium, was tested as a source of enzymes for saccharifying boiled rice to produce a beverage similar to Amazake, a traditional non-alcoholic beverage. The composition of a medium that should leave no unpleasant taste in the Amazake-like product was confined to 1.0% raw cornstarch, 2.0% skim milk, and 0.1% yeast extract. α-Amylase activity and cell growth de-creased in the medium lacking any of the three ingredients. Production of α-amylase was stimulated by soluble starch as well as raw cornstarch, but neither by glucose nor sucrose. When 100 ml of the culture broth was mixed with 16 g of rice after boiling and incubated at 55°C for 24 h, the obtained fluid had an acceptable sweet and sour taste.