ASCORBIC ACID IN TOMATOES 



19 



Table 3. — Biological Assay of Ascorbic Acid in Recanned Tomato Juice 



Amount Fed Daily* 



4.50 



4.75 



5.00 



5.25 



5.50 



5.75 



6.00 



6.50 



7.00 



7.50 



8.00., 



. 00 (negative control) . 



36 



♦Three animals were fed at each level. 



STUDY OF ASCORBIC ACID IN RAW TOMATOES" 

 Effect of Variety and Strain'' 



Ninety-eight strains and varieties of tomatoes were grown on experimental 

 plots. In most cases the source of the seed is indicated. All had exactly the 

 same fertilizer treatments and care. Six samples of each variety or strain were 

 used, each sample consisting of a composite portion, 25 to 50 grams, of a firm, 

 ripe tomato from a different plant of each separate variety. Data show that a 

 second extraction of tomato gives an average increase of 10 percent in the total 

 determined content of ascorbic acid. Therefore, 10 percent was added to the 

 values obtained on the 98 varieties and strains and the total expressed both in 

 milligrams of ascorbic acid per gram of tomato, and as international units per 

 ounce (Table 4). 



The results show considerable variation in the ascorbic acid content of tomato 

 varieties. Because of this variation, due consideration should be given to variety 

 when comparing tomatoes to other products containing the antiscorbutic factor. 



Hahn and Gorbing (1933) found that fertilizer constituents influenced the 

 amount of ascorbic acid in spinach. The differences in ascorbic acid content of 

 tomato varieties cannot be attributed to the fertilizer in this experiment, as all 

 varieties received the same nutrients and care. The soil on all experimental 

 plots was of the same type, sandy loam. 



Ten varieties contained 200 or more units per ounce. These are truly excellent 

 sources of ascorbic acid and compare very favorably with oranges or grapefruit. 

 Among the varieties are several new strains developed by the Massachusetts 

 Field Station at Waltham, Massachusetts. Forty-eight varieties or strains, 

 about one-half of the total, yielded between 150 and 200 units per ounce. A 

 number of the leading commercial varieties are grouped in the range 140 to 185 

 units per ounce. Attention is called to variations found among different fruits 

 of the same variety. Definite conclusions cannot be drawn because of this varia- 



^'\cknowledgement is gratefully made to Professor G. B. Snyder of the Olericulture Department, 

 who supervised the collection of seeds and the culture of the tomatoes. 

 'For a preliminary report see Maclinn, Fellers, and Buck (1937). 



