The sweet Japanese cooking wine called mirin is traditionally made from glutinous rice. To develop a mirin-Iike sweetener, high-starch produce (potatoes, edible lily bulbs, pumpkins) produced in Hokkaido was examined as raw materials. The antioxidative activities of these materials were also investigated. Koji (a preparation that is obtained by growing Aspergillus oryzae on boiled rice, barley, soybeans or the like and that is used as a starter for the fermentation in sake and soy-sauce production), heat-treated peeled potato, shochu spirits containing 35%( v/v) ethanol or 35% (w/v) aqueous ethanol, and commercially available powdered amylase and protease enzyme were mixed in a weight ratio of 0.4: 2.0:1.0:0.005. After incubation at 30’C for 45 or 60 days, the potato mirin was recovered. Lily bulb and pumpkin mirins were prepared similarly.

1) The yield ratio and glucose recovery ratio were slightly higher for enzyme-treated (0'15%) potato mirin than for enzyme-untreated potato mirin; the total nitrogen recovery ratio was greatly increased by enzyme addition.

2) The yield ratio of the potato mirin (70.5%) as higher than those of the enzyme-treated pumpkin and lily bulb mirins.

3) The total sugar content (glucose) of the enzyme-treated potato mirin (25.2%) as about a half that of commercially available rice mirin. The total amino acid content (1.4%) was about 6 times higher than that of commercial rice mirin.

4) The antioxidative activity of the enzyme-treated potato mirin, measured as butylated hydroxyanisole (BHA) equivalent, was 109 mg / 100 ml. This was the highest among the potato, lily and pumpkin mirins.