FRUCTOSE, LAEVULOSE

This article appears in Volume V11, Page 253 of the Encyclopedia Britannica.

Encyclopedia Britannica - Main :: FRA-GAE

FRUCTOSE, LAEVULOSE , or FRUIT-

SUGAR

SUGAR

, a carbohydrate of the

formula

FORMULA
FORMULA (Lat. diminutive of forma, shape, pattern, &c., especially used of rules of judicial
procedure
- PROCEDURE (Fr. procedure, from Lat. procedere, to go for-ward)
)

CsH12O6. It is closely related to

ordinary

ORDINARY (med. Lat. ordinarius, Fr. ordinaire)

glucose

GLUCOSE (from Gr. - twais, sweet)

, with which it occurs in many fruits, starches and also in honey. It is a hydrolytic product of inulin, from which it may be prepared; but it is more usual to obtain it from " invert

sugar

SUGAR

," the mixture obtained by hydrolysing cane sugar with sulphuric acid. Cane sugar then yields a syrupy mixture of

glucose

GLUCOSE (from Gr. - twais, sweet)

and fructose, which, having been freed from the acid and concentrated, is mixed with water, cooled in ice and

calcium

CALCIUM [symbol Ca, atomic weight 40.0 (o= x6)]

hydroxide added. The fructose is precipitated as a saccharate, which is filtered, suspended in water and decomposed by carbon dioxide. The liquid is filtered, the filtrate concentrated, and the syrup so obtained washed with cold alcohol. On cooling the fructose separates. It may be obtained as a syrup, as fine, silky needles, a

white

crystalline powder, or as a granular crystalline, somewhat hygroscopic

mass

. When anhydrous it melts at about 95 C. It is readily soluble in water and in dilute alcohol, but insoluble in absolute alcohol. It is sweeter than cane sugar and is more easily assimilated. It has been employed under the name diabetin as a sweetening agent for diabetics, since it does not increase the sugar-content of the urine; other medicinal applications are in phthisis (mixed with

quassia

QUASSIA

or other

bitter

BITTER, KARL THEODORE FRANCIS (1867– )

), and for children suffering from tuberculosis or scrofula in place of cane sugar or milk-sugar.
Chemically, fructose is an oxyketone or ketose, its structural

formula

being CH2OH(CHOH)m.COCH2OH; this result followed from its conversion by H. Kiliani into methylbutylacetic acid. The form described above is laevo-rotatory, but it is termed d-fructose, since it is related to d-glucose. Solutions exhibit mutarotation, fresh solutions having a specific rotation of -104.0, which gradually diminishes to 92. It was synthesized by Emil Fischer, who found the synthetic sugar which he named a-acrose to be (d+l)-fructose, and by splitting this mixture he obtained both the d and 1 forms. Fructose resembles d-glucose in being fermentable by yeast (it is the one ketose which exhibits this property), and also in its power of reducing alkaline copper and silver solutions; this latter property is assigned to the readiness with which hydroxyl and ketone groups in close proximity suffer oxidation. For the structural (stereochemical) relations of fructose see SUGAR.

End of Article: FRUCTOSE, LAEVULOSE

If you wish, you can link directly to this article.

<a href="http://jcsm.org/StudyCenter/Encyclopedia/FRA_GAE/FRUCTOSE_LAEVULOSE.html">
FRUCTOSE, LAEVULOSE
</a>

(Previous)
FROUDE, JAMES ANTHONY (1818-1894)

(Next)
FRUGONI, CARLO INNOCENZIO MARIA (16921768)

JCSM was founded in 1997 and exists to help the community and bring people into a life-changing and productive relationship with Jesus Christ. JCSM offers over 200,000 free web pages, including its weekly inspirational emails that were sent continuously for over a decade.

Jesus Christ Saves Ministries
P.O. Box 9297
San Diego, CA 92169
1-888-887-0417 or Email