8 



DETERMINATION OF SUGARS IN GRAIN AND CATTLE FOODS. 



sample, so that this method could be used. The results of this work 

 are given in the following table: 



Check analyses of sample No. 7900 (molasses feed) , using several methods. 



i Results by Mr. Given. 

 8 Results by Mr. Straughn. 



* Results by Mr. Jacobs. 

 < Results by Mr. Bryan. 



The results obtained with alcohol, either by digestion or by extrac- 

 tion, agree among themselves, as do also the results with hot water 

 and cold sodium carbonate digestion, but comparing the figures 

 obtained when water was the extracting agent with those obtained 

 when alcohol was "used, there is noted an increase of over 3 per cent 

 in total sugars extracted by water. Unfortunately after this work 

 was done none of the sample was left on which to study the cause of 

 this difference. It might result (1) because the alcohol did not 

 extract all the sugars; (2) because the sodium carbonate did not 

 inhibit the action of the enzyms; (3) because the cuprous oxid was 

 badly contaminated in the sodium carbonate digestion; (4) because 

 the sodium carbonate method extracts substances which reduce 

 Fehling solution, especially on inversion, that are not extracted by 

 alcohol. 



The first suggestion is answered by the fact that extraction hi a 

 Soxhlet extractor was run to a point at which no reaction for sugar 

 with of-naphthol was given and the results of this method were prac- 

 tically the same as those obtained by the alcohol digestion method. 

 Also in experiments using 12 grams of sucrose as the material for 

 extraction by the alcohol method in one test and 12 grams of invert 

 sugar in another, there was no sugar remaining undissolved and no 

 sugar was precipitated by the addition of 95 per cent alcohol to the 

 300-cc mark. This shows that the percentage of sucrose and invert 

 sugar up to 100 per cent would be soluble in the alcohol treatment. 

 The second explanation was shown to be unsatisfactory by extracting 

 the material with boiling water; the results obtained were practically 

 the same as by the sodium carbonate extraction method in the cold 

 and, therefore, the activity of enzyms could not have caused the 

 difference. 



