XX] FLAVORING EXTRACTS 261 



Place a portion of the filter with the attached resins in a few cc. of dilute potas- 

 sium hydroxid solution. The resins are dissolved, giving a deep red solution; 

 acidify, and the resins are precipitated. 



Dissolve a portion of the resins in alcohol. To one portion add a few drops of 

 ferric chlorid solution; to another portion hydrochloric acid; neither produces any 

 marked change in color. Most resins, however, in alcoholic solution give color 

 reactions with ferric chlorid or hydrochloric acid. 



To a portion of the filtrate obtained above add a few drops of basic lead acetate 

 solution. The precipitate is so bulky as to almost solidify, due to the excessive 

 amount of organic acids, gums and other extractive matter. The filtrate from 

 this precipitate is almost colorless. 



Test another portion of the filtrate from the resin for tannin with a solution of 

 gelatin. Tannin is present in varying but small quantities, but should not be 

 present in great excess. 



12 METHYL ALCOHOL.-TENTATIVE. 



Proceed as directed under X\1I, 16, 17 or 18, using the distillate from tlie de- 

 termination of alcohol, 2. 



13 COLOR VALUE.— TENTATIVE. 



Pipette 2 cc. of the extract into a 50 cc. graduated flask and make up to the mark 

 with a mixture of equal parts of 95% alcohol by volume and water. Determine 

 the color value of this diluted extract in terms of red and yellow by means of a 

 Lovibond tintometer, using a 1 inch cell. To obtain the color value of the original 

 extract, multiply the figures for each color by 25. 



1 4 RESIDUAL COLOR AFTER PRECIPITATION WITH LEAD ACETATES-TENTATIVE. 



Determine the color value, in terras of red and yellow, of the filtrate from the 

 lead acetate precipitate as obtained in 4, using a 1 inch Lovibond cell. Multiply 

 the reading by 2 to reduce the results to the basis of the original extract. If the 

 actual reading of the solution is greater than 5 red and 15 yellow, as may happen 

 if the extract is highly colored with caramel, a ^ or i inch cell should be employed, 

 and the readings multiplied, respectively, by 4 or 8. Divide the figures for red and 

 yellow, respectively, by the corresponding figures of the original extract and mul- 

 tiply the quotients by 100, to obtain the percentages of the 2 colors remaining in 

 the lead acetate filtrate. 



Calculate also the ratio of red to yellow in both extract and lead acetate filtrate. 



COLORS INSOLUBLE IN AMYL ALCOHOL. 



15 Modified Man<h MclJiod— Tentative. 



Proceed as directed under XVII, 22, using 25 cc. of the extract and shaking with 

 25 cc. of the Marsh reagent instead of 20 cc. 



16 COLORING MATTERS OTHER THAN CARAMEL.-TENTATIVE. 

 Proceed as directed under XI. 



LEMON AND ORANGE EXTRACTS. 



17 SPECIFIC GRAVITY.-TENTATIVE. 

 Determine the specific gravity at "^^ by means of a pycnometer. 



