I20 ORGANIC AGRICULTURAL CHEMISTRY 



EXPERIMENT STUDY XXIII 



Disaccharoses 



(i) Sucrose or Cane Sugar, (a) Test a lo per cent cane sugar 

 solution with Fehling's solution as in Experiment XXII, 2. (b) To 

 5 c.c. of sugar solution, add i.o c.c. of dilute (i : i) HCl, boil for 5 

 minutes. Neutralize excess of acid with Na2C03 and then test with 

 Fehling's solution, (c) Heat a little cane' sugar carefully in a test 

 tube. Notice darkening in color and characteristic odor (caramel). 



(2) Repeat (i, a) and XX, 3 with maltose (malt sugar). 



(3) Repeat {1, a) and XX, 3 with lactose (milk sugar). 



POLYSACCHAROSES (NOT SUGARS), (CeHioOs)* 



The polysaccharoses, or more strictly speaking those poly- 

 saccharoses not sugars, for the disaccharoses are of course poly- 

 saccharoses, include the common and very widely distributed 

 substances, starch, dextrin, cellulose, and the less common glyco- 

 gen found in animals. 



Hydrolysis. — The formula for the polysaccharoses is 

 (CeHioOs)^;. The size of the molecule is unknown, but it is 

 probably quite large. Like the disaccharoses these polysac- 

 charoses are hydrolyzed by enzymes, and by boiling with acid. 

 They each yield the monosaccharose glucose. 



This hydrolysis of polysaccharoses to monosaccharoses is 

 connected with several very important processes both natural 

 and industrial. The natural processes occur in both plants and 

 animals. In the green leaves of plants the carbohydrate, starch, 

 w^hich has been built up by the photosynthetic action of the 

 leaves is converted by means of the enzyme diastase into maltose, 

 and then by maltase enzyme into glucose. In all starch-con- 

 taining seeds, when germination begins, the starch is converted 

 by the same enzymes into these products. This process when 

 produced artificially is known as malting, and the germinated 

 seed or grain containing both glucose and maltose sugars is known 

 as malt. By a completion of the enzyme action by means of 

 zymase alcoholic fermentation takes place and the glucose 



