SUCROSE, CANE SUGAR, OR SACCIIAROSE. This is commercially the most important sugar. It and the products of its hydrolysis, 'invert sugar,' and the sugars that compose 'invert sugar' (d-glucose and d-fructose) are the most impor tant sugars, considered from the point of their wide distribution in fruits and vegetables used for food by man and the lower animals. (For the commercial sources of cane sugar, see SUGAR, :MANUFACTURE OF.) White granulated sugar, whether made from sugar-cane or beet roots, contains between 99 and 100 per cent, of pure sucrose or cane sugar. In many plants it is found associated with 'invert sugar,' which seems to be changed to cane sugar during tbe process of ripening. When cane sugar is hydro lyzed by the action of acids or enzymes, each molecule yields one molecule of d-gIncose and one molecule of d-fructose, a mixture called 'invert sugar,' as explained above.
Cane sugar is readily crystallized in the form of monoclinic hemihedral tables which contain no water of crystallization. These crystals are well exemplified in loaf sugar, rock candy, and granulated sugar, the coarseness of which de pends upon the size of the crystals. It dissolves in about one-half of its weight of water and is much more soluble in hot water; it is dissolved with difficulty in strong alcohol. Its specific gravity is 1.606. It melts at C. F.), and with care may be cooled to a colorless glass like mass; if the temperature is somewhat higher the solidified mass is colored and constitutes the so-called 'barley sugar.' At C. F.) decomposition and marked coloration begin. cara
mel is formed, and as the heat is continued gases are evolved and finally only a black char re mains. Sucrose unites with the oxides of cal cium and other metals to form saccha rates, which are of importance as a means of separating sugar from beet-root molasses. While cane and other sugars in dilute solutions are very prone to undergo fermentation and change, they pos sess considerable antiseptic power in concentrated solution, which is utilized in dried fruits, pre serves, etc.
1,FvuLosE, d-FlorTosE, OR FRUIT SUGAR. This occurs in almost all sweet fruits with d-glucose.
It is crystallized with difficulty, and melts at 95° C. F.). It is readily obtained by hydrolysis of inulin, a polysaecharide which oc curs in many plants. It is less soluble than d glucose, and is as sweet as eane sugar. Levulose is used as a substitute for sugar in the food of diabetic patients. Some of the commercial forms of levulose for this purpose are called `diabetine.' MELITR1OSE, AlELITOSE, OR COTTON SUGAR. This occurs in rather large quantity in Australian manna ( from varieties of Eucalyp tus), in cottonseed meal, and in small quan tities in sugar beets, the manufactured sugar from which sometimes contains small amounts, but the molasses much the greater proportion. It forms characteristic crystals and is strongly dextro-rotatory. When hydrolyzed by acids each molecule yields one molecule of d-glucose, one of d-fruetose, and one of d-galactose.