6 MASS. EXPERIMENT STATION BULLETIN 390 



Minerals 



In addition to being a good source of energy, potatoes are an important source 

 of certain essential minerals. The ash of potatoes is particularly rich in potassium 

 and contains significant amounts of many of the other minerals (Table 2). In 

 evaluating potatoes on the basis of minerals furnished, one must consider the 

 relatively large amounts of this vegetable usually included in the diet as well as 

 the actual composition of the ash per se. 



Potatoes are considered one of the cheapest sources of iron and an economical 

 source of calcium (46). They also contain significant amounts of iodine in many 

 instances, depending upon where they are grown (17). 



In order for a foodstuff to be of value as a source of minerals they must be 

 present not only in significant amounts, but also in a form that can be utilized 

 by the body. This is particularly necessary in the case of iron. "Many of the 

 vegetables known to contain appreciable amounts of iron cannot be considered 

 good sources of this element because it is not available. In potatoes the iron is 

 almost 100 percent available (43). 



THE VITAMIN CONTENT OF POTATOES 



During the past ten years many studies have been made of the vitamin content 

 of potatoes, particularly vitamin C. Potatoes have been found to be a good source 

 of vitamins Bi and C. They also contain measurable amounts of the other vi- 

 tamins. The vitamin content of potatoes is subject to variation according to 

 variety, length of storage, and growing conditions. In a general consideration of 

 potatoes as a source of vitamins in the diet, it is necessary to deal with average 

 values which have been determined by many workers. These values represent 

 the amount of vitamins that the consumer can expect to be present in potatoes. 

 In Table 4 potatoes are evaluated as to their vitamin content. 



Table 4. — Vitamin Content of Potatoes per 100 grams Edible Portion 



Vitamin A 30-50 international units (41) 



Vitamin Bi (Thiamin) 95-165 micrograms (41) 



Vitamin B2 (Riboflavin) 40-80 micrograms (41) 



Vitamin C (Ascorbic Acid) 7-15 milligrams (41) 



Pantothenic Acid 650 micrograms (23) 



Vitamin Be (Pyridoxine) 40 rat units (40) 



Vitamin K small amount (9) 



Biotin small amount (25) 



STUDIES OF THE VITAMIN C CONTENT OF POTATOES 



The present investigation was conducted to determine the vitamin C content 

 of Massachusetts potatoes in comparison with potatoes grown in other sections 

 of the country. Differences in vitamin C content due to variety, storage, and 

 cooking were observed. A preliminary report on this investigation has been made 

 by Lyons and Fellers (29). 



Difi'erences in the vitamin C content of different varieties of potatoes have been 

 reported by Smith and Paterson (44), Mayfield, Richardson, Davis, and Andes 

 (31), Ijdo (22), and Wachholder and Nehring (52). Fixsen and Roscoe (13) have 

 summarized the available data on varietal difference. Up to 10 percent variation 



