8 MASS. EXPERIMENT STATION BULLETIN 354 



fertilized. Wiien soil moisture was adjusted from dry to very moist conditions, 

 ascorbic acid was found to be somewhat lower under the dry conditions. The 

 ascorbic acid content increased rapidly as moisture was supplied to the soil until 

 the fruit approached 95 percent moisture when fully ripe. As more water was 

 applied to the soil, the ascorbic acid content dropped off rapidly even though 

 there was little or no change in the moisture content of the tomatoes. In 10 

 varieties of Italian tomatoes Cultrera (1933) found little relationship between 

 ascorbic acid content and the sugar content, acids, or dry matter during ripening. 



In a personal communication dated March 10, 1939, T. M. Currence of Minne- 

 sota Agricultural Experiment Station reports vitamin C content in terms of inter- 

 national units per ounce, mean of five plots, as follows: Marglobe 113, Valiant 

 124, Scarlet Dawn 110, Red Cap 106, All Red 120 and Harkness 102. He found 

 a variation in Valiant variety from 105 to 140 units and in Red Cap 100 to 119. 

 He points out that environmental factors in growth markedly affect vitamin C 

 content but to a limited extent varietal differences do exist. 



Krauss, Washburn, and Hoffman (1937) found that ascorbic acid was distribu- 

 ted in all parts of the tomato although it was not consistently high in the same 

 part in all varieties. The placental tissue including the gelatinous material in 

 which the seeds are embedded generally tends to be high in ascorbic acid. How- 

 ever, the epidermis is sometimes higher in ascorbic acid than the placental tissue. 

 Cultrera (1933) found less ascorbic acid in peeled tomatoes than in whole toma- 

 toes. Yet Vercellana (1924) found no ascorbic acid in the skin and seeds of the 

 tomato. 



Meager data by Krauss, Washburn, and Hoffman (1937) and Hoffman^ on 

 methods of ripening tomatoes, tend to show that diffused light develops more 

 ascorbic acid than sunlight or darkness. Jones and Nelson (1930) found vine- 

 ripened tomatoes to be better sources of ascorbic acid than either ethylene-treated 

 or storage-ripened tomatoes. House, Nelson, and Haber (1929), using the Bonny 

 Best variety, found that unripe tomatoes were relatively poor in ascorbic acid. 

 Storage-ripened and ethylene-ripened tomatoes were richer than the green fruit, 

 and vine-ripened tomatoes were superior to those ripened by either of the arti- 

 ficial methods. Clow, Stevenson, and Marlatt (1929) studying the commercial 

 practice of ripening greenhouse tomatoes in an atmosphere of ethylene gas, 

 concluded that this method seemed to increase the ascorbic acid content, but that 

 such artificially ripened tomatoes were not quite so potent as tomatoes thoroughly 

 ripened at room temperature. Clow and Marlatt (1930) commented that House, 

 Nelson, and Haber (1929) used only a 4-gram level in feeding guinea pigs. This 

 is a high level where minimum recovery dosage is reported. Using a lower level 

 of feeding. Clow and Marlatt (1930) showed that ascorbic acid develops practi- 

 cally to the same e.xtent whether the ripening takes place on the vine, in a dark 

 room, in a light room, or in an atmosphere of ethylene gas. Their studies confirm 

 those of House, Nelson, and Haber (1929) in showing that there is an increase 

 in ascorbic acid during the ripening process. Also ethylene ripening, though not 

 destructive to ascorbic acid, may inhibit its development in the tomato. 



Canned Tomatoes 



Conflicting reports have been published on the stability of ascorbic acid during 

 the canning processes. The lack of standardized procedure in canning is no 

 doubt a major factor in explaining these discrepancies. 



La Mer (1921) compared one lot of commercially canned tomatoes with raw 



'Hoffman. I. C, 1937. Personal communication. 



