202 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



water and crystallises out as the hot solution cools. In its appear- 

 ance maltosazone is different toglucosazone and lactosazone (Fig. 41) ; 

 also in its melting-point, etc. 



(10) Fermentation. Maltose is fermented by yeast, being con- 

 verted by the enzyme maltase in the yeast into glucose, which yields 

 alcohol and carbon dioxide. 



(n) MoliscJjs Test. Maltose gives Molisch's reaction. 



(12) Rotation. Maltose has a high rotation. The rotatory power 

 of a solution of maltose diminishes when the maltose is hydrolysed by 

 acid. 



Other Disaccharides. 



Trehalose occurs in certain fungi. 



Isomaltose was obtained by Fischer by the action of strong acids on 

 glucose. Its formation from starch, together with maltose, by the action of 

 diastase has not been definitely proved. 



Gentiobiose is obtained from the trisaccharide gentianose by hydrolysis 

 with acids or by the enzyme invertase. , 



Cellobiose has been prepared from cellulose. 



Melibiose is a product of the hydrolysis of the trisaccharide raffinose. 



Turanose is prepared from melicitose. 



Vicianose is present in the glucoside vicianin, obtained from the seeds 

 of the vetch (Vicia augustifolia). 



TRISACCHARIDES AND TETRASACCHARIDES. 



The number of known compounds in this group is small. They are 



Mannotriose. 

 glucose galactose galactose. 



Rhamninose. 

 galactose rhamnose rhamnose. 



Raffinose. 

 fructose glucose galactose. 



Gentianose. 

 fructose glucose glucose. 



Melicitose. 

 glucose fructose glucose ? 



Stachyose. 

 fructose glucose galactose galactose. 



Further details of these carbohydrates are given in Armstrong's monograph, 

 "The Simple Carbohydrates and Glucosides". 



