ROOTS, TUBERS, AND FRUITS 315 



levulose and dextrose. The average composition of 

 lemons is as follows : 



Physical composition. Chemical composition. 



Per cent. Per cent. 



Rind 251035 Solids 10 to 12 



Pulp 25 to 35 Sugar 2 to 4 



Juice 40 to 55 Citric acid 6 to 9 



The ash of the lemon is somewhat similar in composition 

 to the ash of the orange but is present in larger amount. 



431. Strawberries are characterized by containing a 

 high per cent, of water (90 to 92 per cent.). Sugar and 

 malic acid are the materials present in largest amounts 

 while protein, fat, ash and fiber form but a small part of 

 the composition. Coloring materials and essential oils 

 are also present in small amounts. While strawberries 

 are valuable as a food adjunct, they do not supply any 

 appreciable amount of nutrients. It has been estimated 

 that it would require 13 pounds of strawberries to supply 

 the carbohydrates needed for a daily ration to say nothing 

 of the protein which would require 65 pounds additional. 

 The malic and other acids present are valuable because 

 of their antiseptic properties which, added to the appear- 

 ance and palatability, make strawberries a valuable food 

 adjunct. 



432. Grapes vary in composition according to variety. 

 They contain from 15 to 20 per cent, of solid matter. 

 The juice contains from 10 to 15 per cent, or more of 

 sugar in the form of sucrose, levulose and glucose. The 

 tartaric acid, which is found in grapes in larger amount 

 than in other fruits, ranges from i to 1.5 per cent. 

 Grapes do not contain any appreciable amount of protein 



