The Isolation and Characterization of Oligosaccharides from Partial Acid Hydrolysis of Guaran

67 Pages·2.911 MB·English

by  Durso, Donald Francis

PURDUE UNIVERSITY
THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION
BY Do n a l d f r a n z i s d u k s c )
THE ISOLATION
e n title d A N D C H A R A C T £ R 1ZA T/oa/ OF
OLIGOSACCHARIDES F/ao/M PARTIAL- ACID HYDROLYSIS
OF GUAAAU
COMPLIES WITH THE UNIVERSITY REGULATIONS ON GRADUATION THESES
AND IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS
FOR THE DEGREE OF
T)0CTO(i OF PHILOSOPHY
Professor in Charge of Thesis
H ead of School or D epartment
y
/ / _________19
TO THE LIBRARIAN:----
THIS THESIS IS NOT TO BE REGARDED AS CONFIDENTIAL.
PROFESSOR nr CHAROB
CHAD. SCHOOL FORM 9

THE ISOLATION AND CHARACTERIZATION OF OLIGOSACCHARIDES
FROM PARTIAL ACID HYDROLYSIS OF GUARAN
A Thesis
Submitted to the Faculty
of
Purdue University
by
Donald Francis Durso
In P artial Fulfillm ent o f the
Requirements for the Degree
of
Doctor of Philosophy
January, 1951
ProQuest Number: 27714211
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ACKNOWLEDGMENT
The author wishes to express h is appreciation
to Dr. Roy L. W histler for h is guidance and. encourage»*
ment throughout the course of th is work.
TABLE OF CONTENTS
Page
ABSTRACT............................................................................................................. 1
INTRODUCTION.............. 3
LITERATURE SURVEY................................................................................... 6
Structure of Guaran ........................................................................... 6
Other Oligosaccharides Composed of Mannose and
G alactose................................ 10
Mannobioses . ............................................................................. 10
Mannose, Galactose Disaccharides .................................. 12
Tri sacch arid es.............................. 13
Chromatography of Sugars on Activated Charcoal •••• 14
EXPERIMENTAL AND RESULTS................................................................... 18
M aterials............................................................................................... 18
Analytical Methods ................................................... 18
Acid Hydrolysis of Guaran and Guar Flour .................... 19
Hydrolysis Conditions . . . . . . ..................... 19
lodim etric Procedure .......................................................... 20
Optimum Hydrolysis Conditions ........................................* 21
Partial Hydrolysis of Guar Flour .................................... 23
Reversion Experiment ................................................................ 25
Fractionation of Guar H ydrolyzate..................................... 26
Carbon Chromatography ........................................................ 25
Carbon Chromatography of Hydrolyzate ..................... 26
Automatic Fraction C o llecto r.......................................... 26
R efractionation of Hydrolyzate Fractions ............... 29
Disaccharide Fraction ............................................ 29
Page
Tri saccharide F raction ................................................... 31
C rystallization and Characterization of Sugars . . . . 33
Disaccharide Mixture .............................................................. 33
M annobiose..................................... 33
Gralactomanno s e ............................................................................ 34
Periodate Procedure........................................................ 35
T risaccharide............................ 37
DISCUSSION.................................................................................................... 44
Hydrolysis Studies ......................................................................... 44
Charcoal Chromatography....................................... 47
C rystalline S ugars....................................................»................... 49
Structure of Guaran...................................................................... 52
SUMMARY........................................................................................................... 54
BIBLIOGRAPHY............................................................................................... 56
LISTS OF TABLES AND FIGURES
LIST OF TABLES
Table Page
1. Hydrolysis of Guaran and Guar Flour, 2%
Solutions at 80° with Hydrochloric Acid 22
2. Results of Fractionation of Guar Hydrolyzate .. 27
3. Results of Paper Chromatographic Analysis of
Effluents Obtained on Re-fractionation of
Disaccharide Fraction .................................................. 30
,4„ Results of Paper Chromatographic Analysis of
Effluents Obtained on Re-fractionation of
Tri saccharide Fraction ........................................... 32
5* Analyses of Sugars ........................ 38
6. Hydrolysis of Trisaccharide as Followed by
Paper Chromatogram................................................................ 41
7* Results of P artial Hydrolysis of Trisaccharide. 43
LIST OF FIGURES
Figure Page
1. Hydrolysis of Guar Flour, 2% solution,
0.5 N HCl at 8 0 ° ............................................ 24
1
ABSTRACT
The investigation of the products of partial acid
hydrolysis of guaran was undertaken to obtain Information
concerning the structure o f th is galactomannan* Hydrolysis
of a homogeneous Z% solution of the polysaccharide was
accomplished by the action of 0.5 N hydrochloric acid at
80°• An lodim etric titra tio n procedure was developed in
order to follow the progress of reaction*
A m odification of the T iseliu s technique for the
chromatographic separation of sugars on charcoal has been
reported. An automatic fraction collector was devised and
b u ilt for the separation of large amounts of hydrolyzate
by th is technique*
From the hydrolyzate, three crystallin e sugars, two
disaccharides and a trisaccharide have been Isolated,
characterized and their structure established* These
sugars are 4 -(B-D-mannopyrano sy1)-B-IX-mannopyrano se;
6- (*-D-galactopyrano syl ) -B-D-mannopy rano se ; and 4-^6*-(*-D-
galactopyrano syl ) -B-D-mannopy rano syï] -B-D-mannopyrano se,
The second disaccharide and the trisaccharide are new
compounds* The la tter represents the fir st reported isola**
tion of a trisaccharide consisting only of mannose and
galactose.
The sugars isolated are in accordance with the structure
of guaran which had been assumed to be the most probable
2
of four possible structures. The Isolation of these
crystallin e compounds having in tact the linkages present
in the original molecule precludes almost entirely any contri­
butions to the structure of the guar polysaccharide that
might be made by three of the four proposed possible
structures.
The conclusion is that the guar polysaccharide con sists
of a mannose chain linked by B 1, 4* glycosidle bonds and
that, on the average, half of the mannose units have a
galactose residue attached by an<x i ,6 1 linkage# Such a
structure is in complete accordance with a ll the informa­
tion available on the guar polysaccharide.