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MALTOSE. 225
changed by the presence of other inactive substances. The specific
rotation is (a) D = +66.5°.
Saccharose acts indifferently toward Moore’s test and to the ordinary
reduction tests. On continuous boiling it may reduce an alkaline copper
solution, perhaps on account of a partial inversion. It does not ferment
directly, but only after inversion, which can be brought about by an
enzyme (invertin) contained in the yeast. An inversion of cane-sugar also
takes place in the intestinal canal. Cane-sugar does not combine with
hydrazines. Concentrated sulphuric acid blackens cane-sugar very
quickly even at the ordinary temperature, and anhydrous oxalic acid
does the same on warming on the water-bath. Various products are
obtained on the oxidation of cane-sugar, dependent upon the variety of
oxidizing agent and also upon the intensity of the action. Saccharic acid
and oxalic acid are the most important products.
The reader is referred to complete text-books on chemistry for’ the
preparation and quantitative estimation of cane-sugar.
Maltose (malt-sugar) is formed in the hydrolytic cleavage of starch
by malt diastase, saliva, or pancreatic juice. It is obtained from glyco-
gen under the same conditions (see Chapter VII). Maltose is also pro-
duced transitorily in the action of sulphuric acid on starch. Maltose
forms the fermentable sugar of the potato or grain mash, and also of the
beerwort.
Maltose crystallizes with one molecule water of crystallization in fine
white needles. It is readily soluble in water, rather easily in alcohol,
but insoluble in ether. Its solutions are dextrorotatory; and the specific
rotation is variable, depending upon the concentration and temperature,
but is considerably stronger than glucose, 1
and is generally given as
(o0d = +137 to 138°. Maltose ferments readily and completely with
yeast, and acts like glucose in regard to the reduction tests. It yields
phenylmaltosazone on warming with phenylhydrazine for 1^ hours.
This phenylmaltosazone melts at 205° C, and is more soluble in hot
water than the glucosazone. Maltose differs from glucose chiefly in the
following: It does not dissolve as readily in alcohol, has a stronger dex-
trorotatory power, and has a feebler reducing action on Fehling’s solu-
tion; 10 cc. Fehling’s solution are, according to Soxhlet,2
reduced
by 77.8 milligrams anhydrous maltose in approximately 1 per cent solution.
Isomaltose. This variety of sugar, as has been shown by Fischer,3
is produced, as are dextrin-like products, by reversion, and by the action
of fuming hydrochloric acid on glucose. A re-formation of isomaltose
1
See Hoppe-Seyler-Thierfelder’s Handbuch, S. Aufl.
2
Cited from Tollens’ Handbuoh. der Kohlehydrate, 2. Aufl. 1, 154.
5
Ber. d. deutsch. ehem. Gesellsch., 23 and 28.
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