NUTRITIVE VALUE OF POTATOES 



15 



in the present study represent average conser\"ati\e figures which may be used 

 in evaluating the potato nutritionally throughout the winter. 



All methods of cooking caused some destruction of the ascorbic acid of potatoes. 

 The amount of destruction, which varied with the cooking method, ranged from 

 31 to 80 percent. It appears that the speed with which the internal temperature 

 is raised, which in turn determines the activity of the oxidizing enzymes, may 

 be a controlling factor. Boiling whole in the skin, baking, and French frying 

 appear to be the best methods of cooking potatoes from the standpoint of \'ita- 

 min C retention. 



Table 10. — Effect of Various Cooking Methods on Vitamin C Content 



OF Potatoes* 



Cooking Method 



Ascorbic 

 Acid 



Loss of 



Ascorbic 



Acid 



Vitamin C in an 



Average Serving 



(5 14 ounces) 



Mg. per gm. Percent Mg. LU.** 



Raw 0.100 — 14.88 297 



Baked 0.069 31 10.26 205 



Boiled whole, salted water 0.073 27 10.86 217 



Boiled peeled, cut in half 0,053 47 7.88 157 



Boiled peeled, sliced . 040 60 5 . 95 119 



Boiled peeled, salted water 0.055 45 8. 18 163 



Boiled peeled, unsalted water 0.051 49 7.58 151 



Boiled whole, salted water; held 24 



hours in refrigerator 0.026 74 3.86 77 



Boiled, salted water, mashed 0.046 54 6.84 137 



Boiled, unsalted water, mashed 0.031 69 4.61 92 



Boiled, creamed . 020 80 2 . 97 59 



Boiled, fried 0.021 79 3.12 62 



Scalloped 0.036 64 5.35 107 



French-fried 0.067 33 9.96 199 



Boiled whole, cold— salad 0.026 74 3.86 77 



*The Green Mountain potatoes used had been stored at 38° F. for 180 days. 

 ♦♦International Units. 



In the fall and early winter approximately one fourth of man's dail\- requirement 

 of ascorbic acid can be obtained from one average serving of boiled, baked, or 

 French-fried potatoes. In the spring it would be necessary to eat approximately 

 one and two thirds average servings to obtain the same amount of vitamin C. 

 The daily requirement of vitamin C for an adult is estimated at approximately 

 75 milligrams of ascorbic acid or 1500 international units (46). Warmed-over 

 potatoes and potato salad contained so little ascorbic acid that they cannot be 

 considered a source of vitamin C. 



Tests have recently been conducted at this laboratory^ on the effect of re- 

 frigerator storage on the vitamin C and moisture content of foods. The foods 



'McConnell, J. E. W., and Fellers, C. R. Mass. State College. Personal communication, 1942. 



