We investigated the effects of mineral waters on the properties and preference of cooked wash-free rice. We also determined the Ca and Mg amounts of wash-free rice cooked with mineral waters. In the preference sensory tests, wash-free rice cooked with Ca-rich Vittel (300 mg/L hardness) and Mg-rich deep-sea waters (330 and 700 mg/L hardness) were evaluated to be as delicious as wash-free rice cooked with distilled water. Rice cooked with Contrex (1,560 mg/L hardness) and deep-sea water (3,200 mg/L hardness) were evaluated low in color and taste. Wash-free rice cooked with mineral water absorbed almost 100% of Ca and Mg from the mineral water used. These results suggest that wash-free rice cooked with mineral waters can be expected as the source of mineral nutrients.

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We examined difference in productivity of α-EG by the fermentation method using non-glutinous rice and glutinous rice as starch materials. When non-glutinous rice was used as starch material, productivity of α-EG became 1.3 times higher in sake brewing method and 1.8 times higher in mirin (type of sweet sake used for cooking) brewing method compared with glutinous rice was used as starch materials. When α-EG was produced with maltose or isomaltose as sugar substrate, compared with isomaltose, productivity of α-EG of maltose became 1.2 times higher. It was thought that gelatinization of the starch of the materials rice and the action mechanism of the starch degrading enzymes influenced productivity of α-EG by the fermentation method.

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