I i 



The distillation should be conducted at such a rate that 100 cc of the distillate may 

 be obtained in from twenty-five to thirty-five minutes. Occasionally some paraffin 

 is carried over mechanically, and this may usually be removed from the surface of 

 the distillate by means of a wire or glass rod. 



The following results were obtained on ketchups containing a known amount of 

 sodium benzoate: 



Determination of sodium benzoate in ketchup by Method V (West). 



THE DETECTION OF TINNAMIC ACID. 



The statement ha.- ir (|ucntly Keen made that cinnamic acid is being used for the 

 \ai in "f foods, es|>ecially in the case of tomato ketchup. The claim has often 

 been made by those interested in the preservation of ketchup with benzole acid that 

 tin- i'ft-i-in-e of cinnamic acid could not be detected and that firms claiming to use 

 no preservative were preserving with that substance. Two qualitative methods for 

 the deteeii..n of eiiuiamic acid, differing slightly from each other, were elaborated by 

 P. 1'.. iMmbar. I loth of these methods depend u|x>n the well-known fact that cin- 

 namic acid is oxidized to benzaldehyde by dilute chromic acid mixture. 



Method !.( >ne hundred grams of ketchup were treated with 100 cc of water and 5 cc 

 of -iilplniii' a' i'! I to > and the mixture extracted directly with three portions of 

 chloroform, u-inu' "><>. 25, an<i :>eetively. The chloroform extract was made 



alkaline \\ith ammonia ami evaporated to dryness on the water bath. The residue 

 \\a.- di--ol\ed in a -mall amount of hot water, filtered, again evaporated to dryness, 

 and heated to boiling uiih :> cc "f dilute chromic acid mixture (1 part of dilute sul- 

 phuric acid -aturat.d with potassium bichromate and 7 parts water). The odor of 

 ddehyle i> -tron<_:e-t when the mixture is cooled until the fumes of sulphuric 

 acid arc n.", longer apparent . 



Method 2. Two hundred grams of the ketchup are diluted to 500 cc with water, 

 allou !,-, and filtered. An aliquot portion of the filtrate, 250 cc or more, is 



acidified with "> cc of -ulphuric acid (1 to 5), extracted with chlorofprm, and the 

 remainder of the operation conducted as under Method 1. 



The second method appears to be slightly more delicate than the first, although 

 \vii !i either it was possible to detect cinnamic acid in tomato ketchup when present to 

 an extent of 25 ing per kilogram. 



This reaction is also ;iven by cinnamic aldehyde. The method, therefore, does 

 not distinguish of itself between cinnamic aldehyde, resulting from the use of cinna- 

 mon as a flavor and cinnamic acid used as a preservative, except that the amount of 

 cinnamic aldehyde present in the commercial ketchups examined was not sufficient 

 to give a reaction. If cinnamic acid were present in the ketchup, it would be de- 

 tected by the methods used for the detection of benzoic acid. Cinnamic aldehyde, 

 on the other hand, would not be detected by the methods suggested for benzoic acid. 

 The benzoic-acid residue obtained by the evaporation of the chloroform extract may 

 be examined by the cinnamic-acid methods described. 



The iM-rmicidal and antiseptic properties of cinnamic acid were investigated by 

 ( i . \V . St iles, who found them to be very much lower than those of benzoic acid. The 

 preservation of a food, therefore, would require a much larger percentage of cinnamic 



