26 



BULLETIN 123, U. S. DEPARTMENT OF AGRICULTURE. 





37S C^lO/P/rS 



Old and wrinkled potatoes are much improved by cutting off the 

 ends or by partially or wholly paring and soaking in cold water for 

 several hours. In fact, inferior potatoes of any age are much im- 

 proved by paring and soaking. Where potatoes are inexpensive or 

 the parings can be fed to animals, it is often a profitable custom to 

 pare before cooking, since thus imperfections and strong-flavored 

 portions are disposed of, leaving a nearly pure starch, comparable to 

 arrowroot or tapioca and ready for the table as soon as cooked ; this 

 is true notwithstanding that careful investigations have proved that 

 such cooking causes considerable loss of the nutrients in the potato. 

 The way in which foods are cooked has some effect on their food 

 value. In the case of potatoes it has been found that when boiled 

 with the skins removed there is a very considerable loss not only of 

 organic nutrients but also of mineral salts. (Fig. 3.) When boiled 



with the skins on, 

 the loss of nutrients 

 is very slight. In 

 the case of potatoes 

 baked in the jackets, 

 little if any nutritive 

 material is lost. It is 

 self-evident that, if it 

 is desired to cook po- 

 tatoes with as little 

 loss as possible, they 

 should be either boiled or baked with the skins on. When potatoes 

 are the only vegetable obtainable it may be especially important 

 to cook them without paring, so that their mineral salts may be re- 

 tained, but people who use plants and other vegetables freely may 

 be justified in considering chiefly convenience and palatability in the 

 preparation of these tubers. 



Often it is a convenience for the housekeeper who has several dishes 

 to prepare at once just before dinner to have the potatoes pared earlier 

 in the day. If so, they should be put in water with a little salt added, 

 so that they will not turn dark. 



Most good cooks believe that it is wiser to discard the water in 

 which potatoes are boiled, as it is likely to be strong in flavor, rather 

 than to save it for soup making or for some similar use as is recom- 

 mended for the water in which celery, etc., is cooked. ( See Lesson II. ) 

 Potato flour may be found in large groceries and is used in cakes 

 and for thickening purposes. 



SWEET POTATOES. 



Sweet potatoes are not strictly tubers, but tuberous roots. There 

 are many varieties, with different shape and color. Northern mar- 



J¥l7"p./?6 



Fig. 3. — Composition of the potato. The shaded portion 

 represents the average loss of nutrients when boiled with 

 the skin on. 



