IXJ SACCHARINE PRODUCTS 135 



After determining the weight of the alcohol precipitate, dissolve the latter in 

 water and make up to definite volume, using 50 cc. of water for each 0.5 gram of pre- 

 cipitate or part thereof. 



Determine reducing sugars in the solution both before and after inversion as 

 directed under VIII, 18, expressing the results as invert sugar. Calculate sucrose 

 from the results thus obtained and subtract the sum of the reducing sugars before 

 inversion and sucrose from the weight of the total alcoholic precipitate to obtain 

 the weight of the dextrin. 



46 FREE ACID.-TENTATIVE. 



Dissolve 10 grams of the honey in water and titrate with N/10 sodium hydroxid 

 using phenolphthalein as an indicator. Express the results in terms of cc.of N/10 

 sodium hydroxid required to neutralize 100 grams of the sample. 



47 GLUCOSE.-TENTATIVE. 



Qualitative test. — Dilute the honey with water in the proportion of 1 to 1, then add 

 a tew cc. of iodin solution (1 gram of iodin, 3 grams of potassium iodid, 50 cc. of 

 water). In the presence of glucose the solution turns red or violet, the depth and 

 character of the color depending upon the quality and nature of the glucose em- 

 ployed. A blank test with a pure honey of about the same color should be made 

 in order to secure an accurate color comparison. Should the honey be dark and 

 the percentage of glucose very small, precipitate the dextrin which may be pres- 

 ent by adding several volumes of 95% alcohol. Allow to stand until the precipitate 

 settles (do not filter), decant the liquid, dissolve the residue of dextrins in hot 

 water, cool and apply the above test to this solution. A negative result is not 

 proof of the absence of glucose as some glucose, especially of high conversion, does 

 not give any reaction with iodin. ^ 



Quantitative test. — An approximate determination can be made by Browne's 

 formula as follows: Multiply the difference in the polarizations of the invert solu- 

 tion at 20°C. and 87°C. by 77 and divide this product by the percentage of invert 

 sugar after inversion found in the sample. Multiply the quotient by 100 and di- 

 vide the product by 26.7, to obtain the percentage of honey in the sample; 100 per 

 cent minus the per cent of honey gives the percentage of glucose. 



COMMERCIAL INVERT SUGAR.io 



QUALITATIVE TESTS. 

 Fiehe Test {Bryan Modification"). — Tentative. 



48 REAGENT. 



Resorcin solution. — Dissolve 1 gram of resorcin in 100 cc. of hydrochloric acid, 

 sp. gr. 1.19. 



49 MANIPULATION. 



Introduce 10 cc. of a 50% honey solution into a test tube and add 5 cc. of ether. 

 Shake gently and allow to stand for some time until the ether layer is clear. Trans- 

 fer 2 cc. of this clear ether solution to a small test tube and add a large drop of the 

 resorcin solution. Shake and note the color immediately. In the presence of arti- 

 ficial invert sugar, the resorcin assumes immediately an orange-red color turning 

 to dark red. 



