8 BULLETIN 859, U. S. DEPARTMENT OF AGRICULTURE. 



performed by Patterson (36), Bishop and Patterson (12), Voorhees 

 (55), Alwood (3), Alwood and Bowman (4), Bailey and Lodeman (8), 

 Bailey (7), and Jenkins and Britton (26). 



There has been no little difference of opinion concerning the kind 

 of acid occurring in the tomato. As before stated, Bertagnini (37) 

 isolated and identified the acid as citric, while McElhenie (30) be- 

 lieved that oxalic, citric, and malic acids were present. Patterson 

 (36) makes the following statement: 



On following the schemes for the detection of organic acids as given in Fresenius's 

 Qualitative Analysis, paragraph 193, page 342, and Prescott's Organic Analysis, page 

 336, the following acids were found to be present in the concentrated juice of the 

 tomato, viz, malic, tartaric, benzoic, and formic. Malic acid predominated and the 

 others appeared to be present in very small quantities, and as there has been no time 

 for a further investigation as to the relative amounts of these, the whole of the free 

 acids has been calculated as malic acid. 



Passerini (35) claims that the acidity is due chiefly to citric acid 

 and makes the statement: 1 



II sapore dolce e dovuto a glucosi, i quali hanno azione resultante levogira sulla 

 luce polarizzata; l'acidita per la massima parte ad acido citrico, come dimostrammo 

 in altra nota. 



Briosi and Gigli (13) also confirm the presence of citric acid: 2 



Queste esperienze provano nel liquido giallo la presenza dell 'acido citrico; e siccome 

 isaggi con l'acqua di calce e col cloruro di calcio, ed altri che per brevita non rife- 

 riamo, escludono l'acido tartarico, possimao credere che l'acidita stessa sia, almeno 

 per la massima parte dovuta a esso acido citrico, gia riconosciuto nel pomodoro per la 

 prima volta da Bertagnini. 



Alwood and Bowman (4) make the following statement: 

 A qualitative examination showed the presence of citric, malic, tartaric, formic, 

 and succinic acids. Of these the citric acid was by far the most abundant, so that in 

 the quantitative determinations the whole acid was calculated as citric acid. 



Stuber (50) reports that apparently all the acid present was citric, 

 and in no case was tartaric, malic, or succinic acid found. 



Formenti and Scipiotti (19) claim that salicylic acid occurs 

 naturally in the tomato to the extent of 15 to 25 milligrams per kilo- 

 gram of fresh fruit juice. 



Albahary (1) gives the following acids as occurring in the tomato: 

 Mafic, 0.48 per cent; citric, 0.09 per cent; oxalic, 0.001 per cent; 

 tartaric and succinic, traces. He also reports the presence of an 

 amino acid (2). 



Bacon and Dunbar (6) state that — 



the acid of tomatoes has been called by various authors malic, citric, tartaric, and 

 oxalic. The acid is actually citric, as shown." * * * 



1 Translator] as follows: The sweet taste is due to glucose, which has a resulting levorotatory action upon 

 polarized light; the greatest part of the acidity is due to citric acid, as wc have shown in a previous note. 



2 Translated as follows: These experiments prove the presence of citric acid in the yellow liquid; experi- 

 ments with lime water and calcium chlorid and others which we do not mention for the sake of brevity 

 exclude tartaric acid. We may believe that this same acidity is due, at least for the most part, to that 

 citric acid already recognized in the tomato for the first time by Bertagmni. 



