SUGARS. Sugar is the generic name for a class of substances 'belonging to the carbohydrate group. They either occur naturally in the animal or vege table kingdom, or are produced by the action of dilute acids or ferments on another class of bodies known as glu cosides. As a class, they possess a sweet taste, although the degree of sweetness varies greatly with sugars of different kinds. They are readily sol uble in water, less soluble and some times wholly insoluble in alcohol, and insoluble in ether and similar solvents which will not mix with water. Some sugars undergo alcoholic fermentation with yeast, others change from one sugar to another under the action of dilute acids. Many of them are of great value as foodstuffs. Chemically, they consist of carbon, hydrogen and oxygen, the ratio of hydrogen to oxygen being always the same as in water, namely two atoms of hydrogen to one of oxy gen. They are divided into three large groups: (1) The mono-saccharides, hav ing the formula C2I2206. (2) The di saccharides, having the formula C221122 On. (3) The tri-saccharides, having the formula C22TI22026. It will be noticed that the formula for the di-saccharides is exactly twice that of the mono-sac• charides less one molecule of water, 1120; while the tri-saccharides are three times the mono-saccharides, less two molecules of water. All the common sugars belong to one of the first two groups.
1. Mono-saccharides. The best known sugar among the mono-saccharides is Dextrose, commonly known as Glucose, although this latter name is also ap plied to other sugars of a similar char acter. It occurs in large quantities in grapes and hence is sometimes called grape sugar. Hard nodules of this su gar are frequently found in dried grapes or raisins, and it is a common constitu ent of sweet fruits, roots and leaves. and also occurs in honey. It is prepared artificially by boiling a solution of cane sugar with dilute acids, and also from starch by similar means, this process being known as "inversion." So-called corn syrup is inverted corn starch. Dextrose crystallizes in warty masses, but is most familiar in the form of syrup. It is less sweet than cane sugar. Fructose or Levulose, is closely allied to dextrose and occurs with it in many sweet fruits and in honey. When cane sugar is inverted by dilute acids, equal parts of dextrose and levulose are pro duced, the mixture being known as "invert sugar." The other mono-sac charides are of academic interest only.
2. Di-sacch,arides. The commonest di saccharide is Sucrose or Cane sugar. The two chief sources from which it is obtained are the sugar cane and the sugar beet. The former contains 15-20
per cent., the latter seldom more than 16 per cent. It also occurs in many sweet fruits, such as the pineapple, the strawberry, etc. Su crose crystallizes from water in four sided prisms. It melts at C., and on cooling solidifies to a glassy mass known as barley-sugar. Heated to high er temperatures, it loses water and be comes converted to caramel. It is very soluble in water, at ordinary tempera tures dissolving in one-third of its weight of water. Sucrose is the chief constituent of maple sugar.
Maltose or malt sugar is formed from starch by the enzyme diastase. Malt is the grain of barley which has been caused to sprout by wetting it, in heaps, with water and then keeping in a warm moist atmosphere. This sprouting brings about the formation of the diastase. On drying the malt and stirring with water, the diastase acts upon the starch, converting it to maltose. Since the passing of the Prohibition Act, large quantities of malt syrup have been placed on the market as a table syrup, a basis for soft drinks, for candy manufacture and other purposes. Lac tose or Milk-sugar is an important con stituent of the milk of all mammals, in which it occurs to the extent of about 4 per cent., although the precentage varies somewhat. It can be prepared from milk by treating with rennet, when the curd separates, leaving the sugar in solu tion in the whey. On evaporation the crude lactose is obtained. The solution may be purified by filtration through charcoal, and the sugar obtained by crys tallization. Lactose is far less sweet than cane sugar.
The tri-saccharides are of academic interest only, the most important being raffinose.
The action of dilute acids on sugars is of interest and importance. As al ready stated, sucrose undergoes inver sion when its solution is boiled with dilute acids, invert sugar, a mixture of dextrose and levulose, being produced. Similar changes take place in all the di saccharides, under similar conditions, in every case one or more mono-sacchar ides being formed. Milk sugar gives dextrose and galactose, maltose gives dextrose only. The process is one of splitting the sugar molecule in two with the addition of a molecule of water, thus: Coll,20. + ILO = The fermentation of cane sugar, mal tose and lactose by yeast can only take place after inversion. This can be brought about either by dilute acids, as described above, or by an organism known as an enzyme. Ordinary yeast contains the enzyme which inverts cane sugar and maltose, and hence can fer ment both these sugars. Dextrose, fruc tose and invert sugar are fermentable by all yeasts.