Sugar, Starch. Syn. Potato sugar, Fæcula s. This is grape sugar obtained by the action of diastase on starch, in the manner noticed under Gum (British), or by the action of dilute sulphuric acid on starch, or of the strong acid on lignin, or on substances containing it.
Prep. 1. From corn. The corn is first steeped in soda lye; it is then ground wet and passed through revolving sieves to separate the husks and gluten. The starch is carried through long troughs, in which are placed transverse pieces of wood, against which the solid particles of starch lodge, and are thus separated from the washing waters. These wash waters run into a large cistern, where it undergoes fermentation into weak vinegar. The starch in the wet state is then put into a mash tub and treated for from 3 to 8 hours with 1 per cent. of sulphuric acid. The acid liquor is neutralised with chalk and evaporated in vacuum pans; and after being separated from the sulphate of lime it is run into barrels and allowed to crystallise. The grape sugar is sometimes manufactured in blocks 6 inches square, and dried on plaster plates in a current of dry air, as hot air would decolorise it. Large quantities of grape sugar manufactured as above are now produced in the United States, particularly in New Orleans, Buffalo, and Brooklyn. A considerable amount from the same source reaches this country from the Continent, and is employed in our breweries. When specially prepared for the use of the latter the blocks are crushed into small pieces about the size of malt grains. Our excise authorities prohibit the entrance of glucose into a brewer’s premises in the liquid state. In the brewing of pale sparkling ales grape is esteemed more than either cane sugar or malt, and is said to yield a more sound and wholesome liquor, and one free from the acidity, impurity, and treacly sweetness frequently found in beers brewed from raw or inferior sugars. Glucose may also be obtained from cellulose, but the process is too expensive to admit of being practically worked.
2. Potato starch, 100 parts; water, 00 parts; sulphuric acid, 6 parts; mix, boil for 35 or 40 hours, adding water, to make up for evaporation; then saturate the acid with lime or chalk, decant or filter, and evaporate the clear liquor. Under pressure the conversion is more rapid. Prod. 105%.
3. “The starch of potatoes can be converted into glucose by digestion for a few hours with parings of the potato. This operation is largely practised by German farmers in the preparation of food for fattening hogs. An excellent starch sugar can be prepared from Indian corn, which will yield alcohol one eighth cheaper, and quite as pure as that from cane sugar.”[208]
[208] ‘Journ. of Applied Chemistry.’
4. Shreds of linen or paper, 12 parts; strong sulphuric acid, 17 parts (Braconnot; 5 of acid, and 1 of water—Vogel); mix in the cold; in 24 hours dilute with water, and boil it for 10 hours; then neutralise with chalk, filter, evaporate to a syrup, and set the vessel aside to crystallise. Prod. 114%. Sawdust, glue, &c., also yield grape sugar by like treatment. See Lignin.
Sugar from other Sources. Considerable quantities of East Indian cane sugar are yielded by certain Indian palms, the principal of which are the Arenga saccharifera and the Phœnix sylvestris or wild date. Another source whence large quantities of cane sugar are procured is the Sorghum saccharatum or sugar grass. This plant is exclusively grown in Ohio, and yields annually more than 15,000,000 gall. of juice, which is made into sugar.
Melezitose (C12H22O11). From larch manna.
Mycose or trehalose (C12H22O11). From Turkish manna.
Melitose (C12H24O12). From the eucalyptus.