ASCORBIC ACID IN TOMATOES 



31 



28 international units per ounce to 85 units (Table 15). Five samples of tomato 

 juice packed in 1936 were purchased in Amherst. The samples tested, as shown 

 in Table 15, varied from 51 to 80 units per ounce. The conclusion may be drawn 

 from these data that testing one can of a brand of tomato juice may not give a 

 representative indication of the ascorbic acid content of that brand. 



Table 15. — Ascorbic Acid Variation in Different Samples of the Same 

 Commercial Brand of Canned Tomato Juice 



Place and Year 



Amherst, Mass., 1935 



Northampton, Mass., 1935 



Average, 1935 pack 

 Amherst, Mass., 1936 



Average, 1936 pack 



Effect of Exposure 



Opened tin cans of tomato juice were stored at 5° and 21° C. for a period of 

 44 hours. Some of the stored juices were protected from the interchange of air 

 by sealing the openings with paraffin. Results are presented in Table 16. The 

 slight difference in the ascorbic acid content of the paraffined and exposed samples 

 does not warrant sealing of opened containers. 



It should also be noted that room storage (21"^ C.) was more detrimental to 

 these samples than cold storage. Storage at 5° C, the average household re- 

 frigerator temperature, for periods of 20 hours or more resulted in a 10 to 15 

 percent loss of ascorbic acid. 



Table 16. — Effect of Exposure on the Ascorbic Acid Content of Canned 



Tomato Juice 



Storage Period 

 Hours 



Ascorbic Acid, Milligrams per Cc. 



0. 

 20 



44 



