152 PROVISIONAL METHODS FOR ANALYSIS OF FOODS. 



Page 38, 7. Under special tests for process butter I believe the appearance and 

 qualitative tests of the curd are very valuable and should be given. " It. E. Dooliltle. 



Page 38, 7. In the examination of renovated butter by the Reichert process it 

 has been my experience that where Leff man's glycerol method is used the results 

 are uniformly lower than where saponification is effected with alcohol under pres- 

 sure. It is also my experience that renovated butter when saponified, as is my 

 habit, with alcohol, gives Reichert figures upon 5 grams of fat of from 26 to 28.5. 

 Creamery butter, under these circumstances, gives slightly higher figures, ranging 

 from 28 to 32 and very rarely higher. In other words, I find renovated butter to 

 run upon an average two points lower than creamery butter. 



Page 39, 9. I am of the opinion that complete methods should be given for the 

 detection of coloring matters in butter and its substitutes. This is one of the most 

 important subjects that is engaging the attention of food chemists at the present time, 

 because of the anticolor oleomargarine laws which have been enacted in the several 

 States. I see the referee on Coloring Matter does not take up the subject of 

 colors. In my work I make a preliminary test as follows: Take two portions of 

 about 2 grams or more (according to apparent depth of color) of the filtered fat and 

 dissolve each in a separate tube with ordinary ether. To one test tube add 1 or 2 cc. 

 of dilute hydrochloric acid and to the other about the same quantity of dilute potas- 

 sium hydroxid solution; shake both well and let stand. If the commonly used azo- 

 dye be present, the first test tube will give a bright pink to deep wine-red color, 

 according to amount of coloring matter present to the acid solution, while the potash 

 solution of the second tube will be uncolored. On the other hand, if annatto be 

 present the potash solution will be colored yellow, varying in depth with amount 

 present, while the acid solution of the first tube will be uncolored. Having thus 

 found the class the color probably belongs to, I can supply the different tests for that 

 particular class. 



For the azo color used in butter I would call attention to method of J. F. Geisler. b 

 This is a very satisfactory and reliable method. For the vegetable colors, such as 

 annatto, I think the methods of Martin and Cornwall should both be given com- 

 plete. 



Page 40, 3. I would suggest that in my experience it has generally been sufficient 

 to grind the cheese and place it in a muslin strainer upon the water bath for a short 

 time, \vhereupon sufficient fat will be run out and may be filtered and dried. The 

 addition of chemicals is thus wholly avoided. A. 8. Mitchell. 



SPICES. 



Page 55, 1. To detect stems in ground cloves, shake up a little of the material in a 

 test tube with alcohol (or other convenient solvent), allow the sediment to settle, 

 and examine the absorption spectrum of the tincture for the characteristic bands of 

 chlorophyll. It would appear that the green coloring matter is absent from the clove 

 buds, while the stems contain it in considerable quantity. Edgar B. Xenrick. 



Page 55, 3. I would recommend the determination of moisture (adventitious) , as 

 distinguished from volatile oil, by exposure in vacuo over colorless sulphuric acid. The 

 moisture escapes before the volatile oil is appreciably volatilized. The marked dis- 

 coloration of the acid may be taken as indicating the point at which notable quanti- 

 ties of volatile oil begin to come off. (See my work on cloves in Bui. 73. ) A. McGill. 



Comment by Mr. Winton. Certainly a promising method with obvious advantages, 

 which should be studied by the association. Our standards are based, however, on 

 analyses made by another method. 



Am. Chem. Soc., 1902, 22, 150. > Jour. Am. Chem. Soc., 1898, 20,110. 



