Tofu was made with the filled technique using a processed com- mercial soybean milk. To prepare filled tofu, each soybean milk sample was refrigerated at 5 °C for one night. One milliliter of nat- ural bittern (Ako Salt Co., Ltd., Japan) was then added to 40 ml of soybean milk, and the mixture was stirred rapidly in a 50 ml bea- ker at 5 °C. The mixture was then heated in a temperature-con- trolled bath at 80 °C for 30 min, dipped into cold water, and held at 5 °C overnight.