PROCESS OF PJPENHSTG IN THE TOMATO. 9 



Congclon (15) differs from Bacon and Dunbar (6) and claims that 

 the acids are oxalic, citric, and a very slight amount of malic. 

 Oxalic acid is supposed to predominate. 



The preponderance of opinion seems to be that the chief acid in 

 the tomato is citric. 



With regard to the kind of sugar occurring in the tomato there is 

 more uniformity of opinion. Patterson (36) says: 



A few samples of tomatoes were examined for both classes of sugars, the glucose 

 being determined in solutions made up without application of heat; and then a por- 

 tion of this solution was made up in the usual manner for the cane-sugar determina- 

 tions. The amount of increase indicating cane sugar was so small that it was thought 

 to be probably due to substances of a gummy or pectose nature, which are well under- 

 stood to form sugars which act on Fehling's solution when treated'with mineral acids. 

 And from the amount of free acid in the tomato, cane sugar would not be likely to 

 exfst to any extent. 



Briosi and Gigli (13) believe that levulose is the sugar to which the 

 sweetness of the yellow juice is chiefly due. 



Alwood and Bowman (4) say that "it is very probable that no 

 other sugars than those of the glucose kind exist in tomatoes." 



Snyder (46), however, reports the presence of reducing and non- 

 reducing sugars. 



Stiiber (50) finds no change in the sugar content of sugar samples 

 before and after inversion. 



Albahary (2) presents data showing the presence of cane sugar. 



Bacon and Dunbar (6) make the following statement: 



A number of experiments have shown that the sugar of tomatoes is usually invert 

 sugar, with at times a slight excess of levulose. 



Thompson and Whittier (51) were unable to find sucrose in either 

 green or ripe fruits, but reported approximately equal quantities of 

 levulose and dextrose, concluding that in the classification of fruits 

 according to the kind of sugar present the tomato falls in the invert- 

 sugar group. One of the more recent investigators, Bigelow (11), 

 shows that sucrose is probably absent. He states: 



It is probable that the sugar in tomatoes is all invert sugar. This was indicated by 

 some samples which were examined, in which the determination of sugar before and 

 after inversion gave the same results. 



The work herein reported supports the contention of most scientific 

 workers that little or no cane sugar is present in the tomato. It is 

 very probable that where small amounts of sucrose are indicated by 

 the increased reduction of Fehling's solution after acid hydrolysis 

 that the increased reduction is due to other substances than invert 

 sugar. 



Since the data of the present investigation concern the percentage 

 composition of the entire fruit, the comparable results of previous 

 analyses of the whole tomato have been assembled in Table II. 

 175085°— 20— Bull. 859 2 



