This section is from the book "Mrs. Rorer's Vegetable Cookery And Meat Substitutes", by Sarah Tyson Rorer. Also available from Amazon: Mrs. Rorer's Vegetable Cookery And Meat Substitutes.......
Italian pastes, as macaroni and spaghetti
In this group I have purposely placed such manufactured articles as tapioca, arrowroot and sago, because they must be reckoned as carbohydrates in bills of fare.
Starchy vegetables belong to the carbohydrates - heat, energy and fat producers. Cooking is absolutely necessary to make them easy of digestion. Mastication not only breaks them apart, but the ptyalin (an enzym), under the influence of the saliva, an alkaline secretion, begins the conversion of the starches into sugar. The digestion is finished in the small intestine.
All starches in their final digestion are converted into sugars.