88 COOKING AND ITS EFFECT ON FOOD 



vegetables and cereals are indigestible because the digestive 

 juices cannot penetrate the cell wall and grain shells and reach 

 the starch within. Well-cooked plant foods are digestible and 

 nourishing because the digestive juices are able to reach the 

 starch, to act upon it, and to make it ready for bodily use. 



Overcooking. Since cellulose, the woody tissue of plant 

 cells, is tough, and since the shell of starch grains is hard, high 

 temperatures are needed to cook plant foods. But it is possible 

 to overcook plant foods; all of us, for example, are familiar 

 with soggy, overdone, dark potatoes. When starch remains 

 too long in hot water it absorbs sufficient moisture to change 

 it into a soggy, gummy mass which is both unpalatable and 

 indigestible. As soon as potatoes are done; that is, as soon 

 as the starch grains are soft, swollen, and fluffy, the water 

 should be poured off and the potatoes should be kept warm 

 by dry heat. What is true of potatoes is true of other vege- 

 tables ; carrots which stand too long in water lose their crisp- 

 ness and become soggy and unpalatable. 



Cereals contain so little water and so much starch that they 

 must be cooked in a great deal of water and need prolonged 

 heat to swell the abundant starch grains; hence it is almost 

 impossible to overcook them. The ideal way to cook cereals is 

 in a double boiler. 



Loss of food material. Vegetables, like meats, contain 

 extractives, mineral matter, and other food substances which 

 are extracted by water. For this reason green peas, young 

 carrots, new beans, and other tender vegetables should be 

 cooked in a small amount of water, and when they are nearly 

 done, the lid should be removed from the vessel and most of 

 the water should be allowed to evaporate. The water which 

 remains will contain concentrated extractives and nutritive 

 material and should be served with the vegetables. Most old 

 vegetables have strong flavors and hence should be cooked in 



