CHANGES DURING THE SPOILAGE OF TOMATOES. 5 



In the case of samples FS-121, 12:*, and 124 it is to be noted that 

 the molds do not appear to form lactic acid in tomatoes as the 

 bacteria do, but they do seem to remove the citric acid rapidly and 

 to act on the nitrogenous constituents of the fruit in such a manner 

 as to form a considerable quantity of free ammonia. The distillate 

 from FS-121 was alkaline. However, when to 100 cc of filtered 

 juice there were added 10 cc of 10 per cent sulphuric acid and this 

 solution was distilled, the distillate was acid and required 0.9 cc of 

 tenth-normal sodium hydroxid to neutralize it to phenolphthalein. 

 The sample FS-122, similarly treated, gave a distillate which required 

 4.1 cc of tenth-normal sodium hydroxid, and the distillate from 

 sample FS-123 required 22.4 cc, while that from FS-124 required 

 0.8 cc. 



In some types of spoilage it is evident that there is present a certain 

 quantity of combined volatile acids. A large number of good and 

 of poor ketchups were tested for combined volatile acids. None of 

 the known good ketchups contained combined volatile acids, while 

 some of the poorer ones did. However, as some ketchups known to 

 be prepared from decomposed materials did not show combined 

 volatile acids, this determination can not be considered to be a cer- 

 tain index of decomposition, so its use was abandoned. For nitrogen 

 partition, 100 cc of filtered juice was precipitated with 10 cc of 20 

 per cent lead acetate, and the total nitrogen determined in the 

 precipitate (2) and the filtrate (1). 



It is noted hi general that as tomatoes spoil the ammonia obtained 

 by distillation with magnesium oxid increases in amount. The 

 amount of ammonia so obtained is, for a pulp prepared from whole 

 tomatoes, about twice as great as from a skin and core pulp. Thus, 

 for pulped whole tomatoes this figure is found to be about 0.04 per 

 cent, while for pulped skins and cores it runs about 0.02 per cent. 

 Some other results which were obtained in attempting to follow the 

 changes in the nitrogen bodies of tomatoes during spoilage are as 

 follows : 



(1) A solution of potassium ferro-cyanid and acetic acid gives no 

 precipitate in the filtrates from the spoiled tomatoes FS-121-124 or 

 with the filtrates of good ketchups. Boiling with a small amount 

 of nitric acid gives no precipitate in the filtrate from either good or 

 poor ketchups; the same is true of picric acid, phosphotungstic acid, 

 and tarinic acid and salt. There is evidently no protein in such 

 filtrates. 



(2) Nitrogen partition with basic lead acetate solution was de- 

 termined as follows: Make up 25 grams of ketchup to 200 cc with 

 water. Add 10 cc of 25 per cent solution of basic lead acetate. 

 Filter through a 11 cm folded filter, wash four times, filling the 

 filter each time with water, and determine total nitrogen in the 

 filtrate and the precipitate. 



