A generation ago most Americans were well acquainted with a white starchy food called tapioca that was commonly used to prepare a soft pudding in several variations. Today this product rarely appears on our tables.

Tapioca is made from the starch of a fleshy root of the perennial cassava plant. A very ancient food, cassava was probably domesticated in the Amazon basin centuries ago and became the staple starchy food for Caribbean, Central and South American Indians and in Africa.

In America the chief use of tapioca has been to make puddings, often garnished with fruit or served with a sauce. Tapioca is also a valuable thickener for broths, soups and pies, and it can be added to such main dishes as fish and meat loaves. Due to its high starch content, tapioca is very digestible and therefore frequently is served to people on special diets.

Below are some tapioca recipes. OLD-FAHIONED TAPIOCA PUDDING (Serves 6) 1/2 cup large pearl tapioca

3 cups milk 1/4 teaspoon salt 2 eggs, slightly beaten 1/4 to 1/2 cup sugar 1/4 teaspoon vanilla

Soak tapioca in water at least 3 hours, preferably longer. Drain. Combine tapioca with milk and salt in a large saucepan. Bring to a boil, stirring constantly. Lower heat and cook very slowly, stirring frequently for about 45 minutes, until soft. Combine egges with sugar and stir into tapioca. Cook slowly another 5 minutes. Remove from heat and stir in vanilla. Serve warm or chilled. FLUFFY CHOCOLATE TAPIOCA CREAM (Serves 6) 1/4 cup minute tapioca 1/2 cup sugar 1/2 teaspoon salt 3 cups milk 2 squares unsweetened chocolate, grated 1 teaspoon vanilla

Combine tapioca, sugar, salt, milk, chocolate and egg yolks in top of a double boiler and cook over hot water, stirring frequently, until mixture thickens, about 10 minutes. Remove from stove. Beat egg whites until stiff and fold into tapioca mixture. Stir in vanilla. Cool. Serve with whipped cream, if desired. APPLE TAPIOCA (Serves 6) 1/2 cup minute tapioca 1/4 to 3/4 cup light brown sugar 1 teaspoon ground cinnamon 1 1/2 cups water 3 medium tart apples, peeled, cored and sliced 1/2 cup raisins (optional) 2 tablespoons fresh lemon juice 1/2 tablespoon salt 2 tablespoons butter or magarine.

Combine all ingredients in a saucepan. Let stand 5 minutes. Bring to a boil. Simmer, stirring occasionally, until apples are tender and tapioca is cooked, about 12 minutes. Serve hot or cold. If desired, top each serving with a spoonful of vanilla ice cream.