Cut tofu into bite-size pieces and freeze overnight. The next day, thaw tofu for about 1 hour. Mix soy sauce, tomato paste, corn oil, garlic powder and liquid and add thawed tofu; heat in a skillet. In a separate skillet, sauté green pepper, onions and garlic in oil until onions turn clear. Put all ingredients in a pot and simmer together. You may have to add more liquid. Cook for 20 to 40 minutes.