44 MAINE -TATE COLLEGE 



TH£ DIGESTIBILITY OF THE PENTOSE CABBOHY1 

 W. E. Stone akb W. J. Jon 



uring the past five years attention has frequently been called to 

 the occurrence, in many vegetable materials, of the pentosans, the 

 term being applied to those carbohydrate-like bodies, which, upon 



jlysis produce the pentatomic sugars, arabinose or xylc 

 the c be. The presence of pentosans may be recognized 



by heating the materials with moderately concentrated hydrochloric 

 or sulphuric acid, when furfurol is formed and may be letected in 

 the vapors by the intense red color produced upon test paper freshly 

 moistened with anilin acetate. This reaction is very sensitive and 

 may be obtained, almost without- exception, from all vegetable sab- 

 stances. So far as is at present known furfurol is, under these 

 conditions, produced only from the pentose carbohydrates, with the 

 1 of the rare glucuronic acid and its derivatives. The 

 above mentioned test has therefore come to be regarded as : s > 

 cific one. and its wide application seems to justify the statement 

 that the pentosans are common constituents of vegetable substances. 

 Upon closer examination it has also been found that many food 

 materials contain the pentosans in very appreciable quantities, and 

 it becomes desirable therefore to know something of their : 

 value and digestibility. The ordinary food analysis, how- 

 quite ignores these boo them indiscriminately 



with all the other soluble non-nitrogenous compounds under the gen- 

 eral term •' nitrogen-free-extract matter.'' It is only within a si 

 time, that any analytical method 1 - exisle 1 which permits a sepa- 

 rate estimation of these bodies. Such methods are now known i:_ 

 or three modifications, any of which are capable of showing conclu- 



y and with considerable accuracy, the presence of the pen- 

 tosans under all conditions. It has therefore become possible to 



.is article is extracted from Agricultural Science Vol. VII, \o. 1, p. 6. 



fThese extracts are reprinted in this connection partly because of the imports 

 ance of the results and partly to give added prominence and emphasis to ir ? 

 gallon of this sort. Our knowledge of the constitution and properties of many ' 

 food compounds Is sadly deficient, and the most pressing need of to-day in the 

 line of animal nutrition is "work of the kind which Dr. Stone and his associates 

 have done in studying the carbohydrate group. Investigations of this class will 

 be potent in shaping future knowledge and will be quoted long after many of the 

 so eaUed practical experiments are buried in a heap of rubbish. EL J. 



