39 



Bell o employs a reagent prepared by dissolving 1 gram of diphenylamin in 20 cc 

 of 90 per cent alcohol and adding 25 cc pure sulphuric acid. A drop of this solution 

 is placed on a microscopic slide; a small quantity of the powder under examination 

 is spread over a cover glass and the latter placed on the slide, which is then examined. 

 Turmeric develops purple-colored spots throughout the field of vision. This method 

 is said to detect 1 part turmeric in 1,000 parts of mustard and 1 part in 200 of rhubarb. 



PEPPER COLORS, 



Sometimes colored with a preparation of sulpho-azo-benzol-/?-naphthol and 

 barium sulphate (60 per cent). Such a colored powder gives with boiling water a 

 beautiful red filtrate. (1> According to Mennechet c some peppers (those adulterated 

 with the fruit of Myrsine africana L., and Embelia ribes Burm. ) give a yellow- 

 extract w r hen lixiviated with ether. If the ether extract be shaken with several 

 volumes of water and rendered alkaline with ammonia a lilac-red color is produced, 

 soluble in the water solution, but insoluble in the ether solution. If acidified the 

 ether becomes colored again and the water solution decolorized. 



IX. Starch Preparations (Pastry, Macaroni, Nudeln, etc.). 

 COLORS CONSIDERED. 



Egg yellow, saffron, curcuma, orlean, picric acid, Victoria yellow, Martius yellow, 

 naphthol yellow, etc. 



METHOD FOR COAL-TAR COLORS (REICHELMANN AND LEUSCHER}* 



Extract 50 grams of material on water bath with reflux condenser, and 75 cc of 

 acetone for from forty-five minutes to one hour. Pour off the liquid into another 

 flask and distill off acetone. Add 30 cc of water to residue in flask, cool and filter 

 from the fat. The filtrate may be tested for coal-tar dyes by usual methods. 

 Natural egg color will remain in the fat. In testing for tropseolin in pastry, Brebeck e 

 has noticed that wheat, oatmeal, and other flours themselves contain a substance 

 which gives the same violet coloration with sulphuric acid as does tropseolin and 

 that it may be mistaken for the latter. Schmitz has also noticed that wheat gives 

 a violet coloration, but only after some time; and Popp states that the color is 

 due to the action of the acid on the oil contained in the flour. By removing the 

 oil from the material by means of ether no reaction is obtained on flours. 



X. Confectionery. 

 COLORS CONSIDERED./ 



Cochineal and carmine lakes and alumnia lakes of vegetable colors. Carthamic 

 acid, redwood dyes, cherry and beet juices, Chinese and spinach greens, indigo, litmus, 

 archil blue, caramel, licorice, curcuma, kermes, alzarin and purpurin, and coal- 

 tar colors in general. Alkaline buckthorn juice gives a green used for coloring 

 pistache. 



aPharm. J., 1902, 551. 



& Komm. des Arzneibuch, 2, 8. 



cj. pharm. chim., 1901, [6] 14, 557. 



<*Zts. Nahr. Genussm., 1903, p. 175. 



*Zts. offentl. Chem., 1902, 397. 



/ Colors in Confectionery, the official circular of the National Confectioners' Asso- 

 ciation of the United States, February, 1899, contains a useful classified list of colors 

 considered by them harmless or injurious. This list may also be found in Food 

 Inspection and Analysis, 1904, by Leach. 



