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A study of the behavior of inulin in solution

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A study of the behavior of inulin in solution

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Content A STUDY OP THE BEHAVIOR
OP INULIN IN SOLUTION
A Thesis
Presented to
the Faculty of the Department of Chemistry
University of Southern California
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
^7
Wllmer H* Brobst
June 1939
UMI Number: EP41502
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This thesis, written by
Wilraer H. Brobst
under the direction of h}:3~ Faculty Committee,
and a p p ro ved by a ll its members, has been
presented to and accepted by the Council on
Graduate Study and Research in partial fu lfill
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Master of Science
Dean
Secretary
June 1939
Date.
Faculty Committee
( y j < j
TABLE OP CONTENTS
Page
I. INTRODUCTION ...................................... 1
History and Occurrence • • • • • • • 1
*
Extraction • • • • • . . . • • 2
Methods • • • . • • • • • • 2
Chemical Properties • • • • • • • 3
Physical Properties • • • • • . . 5
Uses • • • • • • • * • • • • 6
Purpose of Investigation • • • • • • 6
II. EXPERIMENTAL......................... 8
General Procedure and Explanations • • • • 8
The Effect of Alcohol Washing • • • • • 9
The Effect of Varying the pH • • • • • 10
The Effect of Washing With Water at 0°and at 25°C. 13
The Ratio of Inulin to Water « • • • • 15
The Effect of Time of Standing • • • • • 17
The Effect of Redissolving • • • • • • 19
A Study of Ash Content of Inulin • • • • 21
The Effect of Standing For Short Periods • • 23
The Effect of Time of Heating • • • • . 25
The Effect of Temperature of Heating . . . 27
A Comparison of Cake and Inulin Solubilities • 29
III. SUMMARY ............................. 32
Conclusion • • • • • • • • • • 35
BIBLIOGRAPHY ........................................... 59
LIST OP TABLES
TABLE PA0E
I. First Recrystallization • • • • • • • 11
II. Inulin Prom Alcohol Wash • • • • • • 11
III. Inulin Prom Water Wash ........................... 11
IV. The Effect of pH • • • • • • • • 14
V. The Effect of Washing With Water at 0°and at 25°0. 16
VI. The Effect of Varying the Ratio of Inulin to Water 18
VII. The Effect of Time of Standing • • • • • 20
VIII. The Effect of Redissolving • • • • • 22
IX. The Effect of Successive Recrystallizations • • 24
X. The Effect of Standing For Short Periods of Time 26
XI. The Effect of Time of Heating • • • • • 28
XII. The Effect of Temperature of Heating • • • 31
LIST OP FIGURES
FIGURE PAGE
I* The Effect of Varying the Ratio of Inulin to Water • 36
2* The Effect of Time of Standing • • • • » 37
3* The Effect of Successive Recrystallizations on the
Ash Content • • • • • • • • • • 38
A STUDY OP THE BEHAVIOR OP INULIN IN SOLUTION
INTRODUCTION
Hi story and Occurrence
Inulin was discovered by Rose in 1804. It is found,
mainly, in underground storage organs of many plants where
it serves as a reserve material. It is also found, to a less
extent, in a number of above ground organs like the seeds of
chicory,1
The fleshy roots and tubers of the family, Compositae,
in which the inulin accumulates, furnish the main source
of this starch-like substance. It has been reported that dry
dahlia roots may contain inulin to the extent of 42 per cent
by weight of the dry material,2 Other substances, which have
been used as a source of inulin, are the chicory roots and
tubers of Jerusalem artichokes. Dahlia roots have been mainly
used as the source of inulin by Weatherby and his associates.
These fleshy roots, which occur in fascicles, vary in inulin
content from 7.3 to 14.7 per cent.
1 Grafe and Vauk, Biochem. Z., 43,424 (1912)
2
Dragendorf, Materialien Zu lener Monograph!e des
Inulins (St. Petersburg, 1870)
Holzman, Studies in the Production of Inulin, A
Thesis Presented to the University of Southern California,
June, 1938
2
Extraction
Different methods have been devised for the extraction
of inulin. The method employed by Kiliani4 is as follows:
’ •Powdered ealeium carbonate is added to the finely ground
material and the mixture is boiled; the albumen is removed
with lead acetate and the inulin is separated by freezing.”
Associated reducing matter may be removed by redissolving in
water and precipitating with alcohol.5
Tanret suggests precipitation with BatOHjg, followed
by decomposition of this precipitate with GOq and then pre
cipitation with 95 per cent alcohol.6
Methods
Three different methods have been employed under the
supervision of Weatherby for the extraction of inulin from
dahlia roots. These methods are (1) hot pressing of the ground
roots; (2) continuous extraction through a diffusion battery;
and (3) superheating of whole roots under pressure.7 At the
present time, the diffusion method seems to be proving the most
4 Kiliani, Ann., 205,145 (1880)
C
Qppenheimer, Die Methodlk der Fermente (Leipzig,
1927) p. 288
6 Tanret, Bull. Soo. Chlm., (3) 9,200,227,625 (1893)
7
Holzman, eg. cit.
efficient and practical on a large scale. This method, which
is a modification of the process used to extract sucrose from
0
the sugar beet, was first used by Black in this laboratory
for extraction of inulin from dahlia tubers.
Chemical Properties
The exact composition of inulin has not been established.
Formerly, it was believed to be composed entirely of fructose
units but recent experiments have shown that some glucose
9
remainders may also be present. For the present, the struc-
10
tural unit may be represented as shown here:
CH.0-
1
C-----
I
HO.C.H
I
E.C.OH
I
H.C----
i
CH. OH
N
Q
Black, Commercial Value of Levulose, A Thesis
Presented to the University of Southern California, June, 1927
Schlubach and Eisner, Ber., 62,1493 (1929)
10
Pringsheim, Chemistry of the Saccharides
McGraw-Hill Book Co., 1932
4
Concerning the molecular weight of inulin, there is
a wide difference of opinion. Prom a yield of 3.7 per cent
1 1
of ls3;4:6 tetramethylfructose, HaworthXJ- has estimated the
molecular weight to he in the range of 5000 with a chain
19
length of 30 fructofuranose units, while Pringsheim
determined the number of fructose units to be 70 with a
molecular weight of 11,000* High as well as low results have
been obtained for the micellar magnitude of inulin in water.
13
Kiliani found a molar weight of 6xCeHio05 which compares
favorably with the 7xCgHiQ05 found by cryoscopic and ebullio-
scopic measurements.-^*15 s Wx^e variation on the molec
ular weight determinations of inulin is probably due to the
fact that in water, inulin can be affected in different ways
independently of hydrolytic action, and still retain the same
optical rotation. At present, the dimeric molar magnitude of
inulin seems to be the most authentic.16
Inulin is not reduced by Pehling’s solution in the cold
nor is there a coloration by iodine solution. It is hydrolyzed
^'blaworth, Hirst, and Percival, J. Chem. Soc. 2834, (1932)
12 Ohlmeyer and Pringsheim, Ber., 66,1292, (1933)
1
Kiliani, op. cit.
14
H. Pringsheim and Fellner, Ann., 462,231 (1928)
H. Pringsheim and J. Reilly, Ber., 61,2018 (1928)
Pringsheim, Chemistry of the Saccharides
by heat in an acid, solution with the rate of hydrolysis depend
ing ot the pH of the solution. Inulin, which has been boiled
in water, will give an osazone with phenyl hydrazine.These
properties show a resemblance between sucrose and inulin.
Physical Properties
T_8
Beilstein has reported the solubility of inulin which
varies from 0.01 gram in 100 ml. of water at 0°C. to 36.5
19
grams in 100 ml. of water at 100 C. and Rieger, in this lab
oratory, has reported the solubility in close agreement with
these results. The specific rotation of a water solution of
pQ
inulin varies with purity. Tanret^ has reported that he
obtained an inulin solution showing a rotation of -40° by
separating out impurities which produce a lower rotation.
Inulin is a hygroscopic substance containing, when air
dried, about 10 per cent water, and decomposes whenever an
17 Bartel, The Purification and Study of Inulin, A
Thesis Presented to the University of Southern California,
June, 1937
Beilstein, Handbuch der Organische Chemle jE, 1095
19
Rieger, Commercial Preparation of Levulose, A Thesis
Presented to the University of Southern California, June, 1934
^ Tanret, op. cit.
6
21
attempt is made to drive out moisture. The most recent reports
state that when an inulin solution is heated to 94°-95° c. and
allowed to cool that doubly refracting sphero-crystals form
and when heated at lower temperatures, acicular crystals separate.
Uses
The value of inulin is determined by the readiness
with which it is hydrolyzed to levulose which is receiving a
Op
considerable amount of attention as a possible diabetic sugar.
Purpose of Investigation
A considerable amount of research work on the extraction,
purification, and subsequent hydrolysis of inulin has been
carried on in the chemical laboratory of the University of
Southern California under the direction of Dr. Leroy S.
Weatherby.2® The main interest is not in inulin itself, but
21 Hoche, Z. ver deut. Zuckerind., 1926,821
22
Pringsheim, og. cit.
23
Bartel, op. cit.
Black, op. cit.
Holzman, op. cit.
Poorman, Problems in Levulose Crystallization, A
Thesis Presented to the University of Southern California,
May, 1938
Rieger, ojd. cit.
Vivian, Levulose, A Thesis Presented to the University
of Southern California, June, 1922
rather in its hydrolytic product, levulose, for which there
04
is an ever growing demand* It has been shown, however, by
various investigations in this laboratory, that before
crystalline levulose can be obtained, the inulin from which
25
it is derived must necessarily be highly purified. Since
this is true, research problems on inulin can be classified
under three heads, (1) the extraction of inulin; (2) the
purification of inulin; and (3) the hydrolysis of inulin.
This particular investigation falls under the second
head or the purification of inulin, and will be concerned
chiefly with the nature of the product as well as the yield
obtained under the different conditions studied. The results
of the investigation can then be applied to large scale
production.
Scientific American, vol. 99, Oct., 1908 McGlumpy,
Eichinger, Hixon, Buchanan, Industrial and Engineering Chemistry,
25 Bartel, o£. cit.
Holzman, op. cit.
EXPERIMENTAL
8
general Procedure and Explanations
The Inulin used in this investigation was extracted
by Weatherby and associates in the laboratory at the University
of Southern California. In most cases, the starting material
was inulin obtained from dahlia roots with one recrystalliza
tion.
A number of experiments were carried out in order to
determine the behavior of inulin, in solution, under different
conditions. The nature of the product obtained as well as the
amount of inulin recovered in each case was carefully noted
and recorded.
The general procedure used in the experiments was much
the same in each case, therefore, in order to avoid unnecessary
repetition, the procedure is given here in addition to a few
explanations of terms used in the discussion.
A weighed amount of inulin was always dissolved in a
definite amount of water at a temperature of 90°to 950 c. The
ratio of the inulin to water will be given in each experiment.
After the inulin was slowly dissolved in the hot water, during
which time it was stirred constantly with a mechanical stirrer,
a weighed amount (|r of 1 per cent) of a decolorizing carbon,
Norit, was added. In a few minutes> a weighed amount (£ of 1
per cent) of filter aid (High Plow Super Cell) was added. After
9
the process was completed, which required from fifteen to
thirty minutes, the solution was filtered while still hot,
with the aid of suction, using a buchner funnel, previously
heated and in most cases prepared with two filter papers and
a pad of filter aid* After the solution was filtered, the
residue was washed two or three times with hot water before
removing the filtrate to covered vessels* The inulin separated
out on cooling, after which the mixture was stirred thoroughly
every twenty-four hours until filtration* The inulin precip
itate obtained from the mixture by filtration held approxi
mately 66 2/3 per cent water and will be referred to in this
discussion as the wcakett* The cake was dried in an oven through
which hot air was forced and which was held at a temperature
of 70° to 80° 0* The inulin dried in one of three different
forms: (1) the least desirable form was granular and horny
which caused it to jump out of the pan while drying and resulted
in a considerable loss; (2) the most desirable form was white,
amorphous, and starch-likej or (3) a mixture of (1) and (2)*
The Effect of Washing the Cake With Alcohol on the Nature
of the Product and the Amount of~Inulin Recovered
Weight of Inulin 300 grams
Volume of Water 1500 cc
The inulin was dissolved in the water, after which the
hot solution was filtered, quickly divided into two equal parts,
and set aside in covered beakers for forty-eight hours* At that
10
time, the inulin, which precipitated, was separated from the
water by filtration.
The first cake was washed on the filter paper three
times with 10 cc portions of ice water, was weighed, and then
was dried in the oven. The second cake was washed three times
with 10 cc portions of 95 per cent alcohol before it was
weighed and dried. The weights and natures of the dried inulin
were noted and recorded.
The entire procedure was repeated on each of the prod
ucts obtained from the first part of the experiment. Tables
I, II, and III give the results.
The most desirable form of inulin was obtained by
washing the cake with alcohol. The amount of inulin recovered
varied only slightly with the method of washing the cake. Two
out of three times the alcohol washing gave the greatest yield.
An increase in the total recovery of inulin with the second
recrystallization showed that most of the impurities were
removed by the first crystallization.
The Effect of pH on the Colloidal Suspension, on the Amount
of Inulin Recovered, and on the Form of the Product? Also
the Effect of Replacing the Supernatant Liquid with Distilled
Water
Weight of Inulin 300 grams
Volume of Water------ 1500 cc
After dissolving the impure inulin in the water and
11
TABLE I
FIRST RECHISTALLIZATIOH
300 gm3. Inulin
CAKE INULIN
TOTAL 1
RECOVERS
Kind of
Wash.
Weight
gms*
Per Cent
Inulin
Weight
gms.
Nature Per Cent
Recover
73.8$
A
Alcohol 349 32.1 112
White
Amorphous 74.8
Water 340.5 32.1
.1.1Q.
Granular
Horny 72.8
TABLE II
INULIN FROM ALCOHOL WASH
112 gras* Inulin
CAKE INULIN
TOTAL
RECOVERY
Kind of
Wash
Weight
gms.
Per Cent
Inulin
Weight
gms.
Nature Per Cent
Recover
93$
Alcohol 163.8 32.5 53
White
Amorphous 94.9
Water 152 33.6 51
Granular
Horny 91.2
TABLE III
INULIN FROM WATER WASH
110 gms. Inulin
CAKE INULIN
TOTAL
RECOVERY'
Kind, of
Wash
Weight
Effii fent
Weight
gms.
Nature Per Cent
Recover
93.3$
Alcohol 141 35.5 50
White
Amorphous
91.5
Water 150 , 34.8 , 52
Granular
Horny 95
12
filtering the solution, four 100 ce portions were drawn from
the filtrate and placed in covered beakers* The remainder of
the filtrate was divided equally into two parts*
The four 100 cc portions were cooled to room tempera
ture* 0*5 cc of concentrated HC1 was added to the first
portion; to the second was added 0*5 cc of concentrated HClj
and to the third, 0*1 cc of concentrated HC1 was added* Ko
acid was added to the fourth portion and it served as a control
for the rest. The cooling was necessary in order to prevent
hydrolysis which takes place readily at higher temperatures*
Each of the six separate portions was allowed to stand
for seventy-two hours* All except one of the large portions
were filtered at that time and the cakes dried. The supernatant
liquid from the other large portion was siphoned off and re
placed with 100 cc of distilled water and the mixture stirred.
In this manner, the supernatant liquid was removed every
twenty-four hours and replaced each time with twenty-five cubic
centimeters of water less than the preceding time until the
amount added was only 25 cc* The mixture was then filtered
and the cake dried. The filtrates in each case were discarded*
Following this procedure, it was found that a slightly
acid condition was effective in removing the colloidal
suspension but the advantage gained was offset by the fact
that hydrolysis had lowered the yield and also darkened the
product* It was found that the greater the hydrogen-ion
13
concentration, the less the yield and the darker the product.
In order to show that the darkening was not due to an insuf
ficient removal of acid in washing the cake, the experiment
was performed a second time. The cake was washed twice with
5 cc portions of a 50 per cent water solution of alcohol and
then twice with 5 cc portions of 95 per cent alcohol. On drying
the cake, a dark product was again obtained indicating that the
acid produced the chemical change which resulted in the colored
product, previous to the washing of the cake.
Removing the supernatant liquid and replacing it with
distilled water only cut down the amount of inulin recovered.
Table IV shows the result of this experiment.
The Effect of Washing the Cake With Water at 0° and at 25° C.
on the Amount of Inulin Recovered
Weight of Inulin --- 300 grams
Volume of Water------ 1500 cc
This time, the hot filtrate was divided into four
equal parts and allowed to stand. After forty-eight hours,
each part was filtered separately. The first cake was not
washed. The second cake was taken from the filter paper, placed
in a beaker with 50 cc of water, stirred thoroughly, and
filtered again. This was repeated twice* The third cake was
washed on the filter paper with 10 cc portions of water at
approximately 25 C. (room temperature). The cakes were
sucked dry in each case and the filtrates saved and evaporated
14
TABLE IV
THE EFFECT OF pH
300 gms. Inulin
CAKE INULIN FILTRATE
Portion Weight
gms.
Per Cent
Inulin
Weight
gms.
Nature Per Cent
Recover
0.5 cc*
Con. HC1 23.5
Very
Dark Clear
0.3 cc.
Con. HC1 27.5 Dark Clear
0.1 cc.
Con. HC1 34.3
Slightly
Dark
/
Clear
No Acid 39.3 White
Slightly
Cloudy
Larger
Portion 240. 39.3 94
Granular
Horny 82 Cloudy
Replaced
Liquid 260.3 34.2 89
Granular
Horny 78 Cloudy
to dryness.
A greater amount of purified inulin was recovered when
ice water was used for washing the cake. However, the amount
o
recovered from washing with water at 25 C. was only slightly
less. Taking the cake and washing it successively in water
reduced the amount recovered considerably and did not improve
the nature of the product. It was noted, however, that the last
filtrate from this procedure was quite clear. Table V shows the
result of this experiment.
The Effect of Varying the Ratio of Inulin to Water on the
Nature of the Product and the Amount of Inulin Recovered
Five, one-hundred gram samples of inulin were weighed
out and each one dissolved in a different amount of water at
o o A
90 - 95 G. Except in one case, the solutions all stood for
forty-eight hours before filtering. This one was stirred con
stantly with an air stirrer for twenty-four hours before
filtering. The nature of the product and the amount of inulin
recovered were recorded.
The greatest amount of inulin was recovered and the
most desirable form was obtained when the ratio of the inulin
to the water in which it was dissolved was 1 to 4. The per cent
of inulin recovered in this case was 81.5 compared with 80.7
for a ratio of 1 to 5. Stirring continuously for twenty-four
hours with a ratio 1 to 8, gave a better yield than the same
16
TABLE V
THE EFFECT OF WASHING WITH WATER AT 0° AND AT 25°C.
300 gms. Inulin
Treatment
of
Cake
Control
Cake
Not
Wasiied
Stirred
With 50c<
Water
3 Times
Washed
With
Ten 10 cc
Portions
Tee .Water
Washed
With
Ten 10 cc
' Portions
Water
at
Cake
Weight
OTIS.
173 121.9 143.1 142.2
Per Cent
Inulin
33.8 45 40.4 40.2
Dry
Inulin
Weight
58.3 54.7 57.9 57.2
Nature
Granular
Horny
Same Same Same
Per Cent
Recovered
77.9 72.9 77.2 76.2
Filtrate
1?VQT5nT,flt, 1 pr
Weight of
Residue
8.8 12.5 4
to
Dryness
Per Cent 11.7 16.7 5.4
Total %
Recovered
76
17
ratio without stirring* The amount recovered was much less
than for the 1 to 4 ratio and the form was less desirable*
Table VI gives the result of this experiment*
The Effect of Varying the Time of Standing on the Amount
of Inulin Recovered
Weight of Inulin 300 grams
Volume of Water------ 1500 cc
The inulin was dissolved in the water at 90°- 95° C*
Norit and filter aid were added and the solution filtered
hot after which it was divided into four equal parts* The first
part was filtered after twenty-four hours, the second after
forty-eight hours, the third after seventy-two hours, and
the fourth after ninety-six hours* Each mixture was stirred
every twenty-four hours until time to filter* The cafces were
washed in each case with three 15 cc portions of ice water,
weighed, and dried. The dry inulin was weighed and its nature
noted* The filtrates were evaporated to dryness*
This experiment showed that the greatest amount of
inulin was recovered after seventy-two hours of standing* If
it was left standing any longer than this, fermentation set
in and lowered the yield* This lower yield was shown in the
fourth part which stood ninety-six hours and gave a yellow
product* If not well covered, fermentation set in even before
seventy-two hours had passed* The nature of the product did
not seem to vary with the length of time the solution stood
18
TABLE VI
THE EFFECT OF VARYING THE RATIO OF INULIN TO WATER
100 gms. Inulin in Each. Case
Hours Stood
Before Filtration
48 48 48 48 24
Ratio of
Inulin to Water
1:4 1:5 1:6 1:8 1:8
Stirred
Cake
Weight
gms.
235.3 257.7 204.9 145.5 131.3
Per Cent
Inulin
34.7 31.4 34.7 38.8 43.4
Dry
Inulin
Weight
gms.
81.5 80.7 70.9 56.2 57
Nature
White
Amor
phous
Mixture
Granular
Horny
Granular
Horny
Mixture
Per Cent
Recovered
81.5 80.7 70.9 56.2 57
. Filtrate
Evaoorated
Weight of
Residue
10.7 11.8 21.5 35.8 34.1
to
Dryness
Per Cent 10.7 11.8 21^5 35.8 34.1
Total
Recovered
69.2$
......................... .......................i------------------------------------------------------------------ — -----------
19
before filtering. Table VII gives the result of this experiment.
The Effect on the Colloidal Suspension of Redissolving the
Inulin: Also the Effect of Stirring Continuously When the
Ratio of inulin to Water Was 1 to 5
Weight of Inulin — 500 grams
Volume of Water — ---- 1500 cc
It was noted that a colloidal suspension was always
formed in the filtrate from which the inulin precipitated when
cooled. An effort was made in this experiment to throw down
this suspension and thus to increase the total amount of
inulin recovered from recrystallization. The inulin was dissolv
ed in the water, and after the addition of Norit and filter aid,
the solution was filtered and divided into five equal parts.
The level of the solution was marked and the level of water
brought up to this mark after each redissolving process.
One of the mixtures was filtered after twenty-four hours,
o
while three of the others were redissolved by heating to 85 C.
with constant stirring and then set aside to cool. After forty-
eight hours, the second mixture was filtered and the remaining
two redissolved as before. The third was filtered after seventy-
two hours and the fourth, which was redissolved after twenty-
four, forty-eight, and seventy-two hours, was filtered after
ninety-six hours. The cakes were washed, weighed, and dried*
in the usual manner and the filtrates evaporated to dryness.
20
TABLE VII
THE EFFECT OF TIME OF STANDING
300 gms. Inulin
Hours of
Filtration
24 48 72 96
Cake
Weight
gms*
167 180 177.7 183.8
Per Cent
Inulin
33.3 34.7 35.9 33.1
Dry
Inulin
Weight
gms.
55.8 62.5 63.5 60.8
Nature Mixture Same Same
Slightly
Yellow
Per Cent
Recovered
74.5 83.5 84.9 81.1
Residue
From
Filtrate
Weight
gms*
12.6 9 7.7 6.3
Per Cent
16.8 12 10.2 8.4
Total
Recovered
80**8#
21
The fifth mixture was stirred constantly for twelve
hours from the time the filtrate was divided* It then stood
for another twelve hours before it was filtered* This was done
to determine the effect it would have on the form of inulin
recovered* The same experiment was performed previously with
a 1 to 8 ratio*
Redissolving the inulin did not remove the colloidal
suspension; in fact, it increased it so that the amount of
inulin recovered was lowered* In one ease, a supersaturated
solution was formed on redissolving but came down after the
next heating* The mixture, which was redissolved once, filter
ed slowly and the filter paper was removed with difficulty*
Stirring the 1 to 5 mixture for twelve hours did not improve
the form of the inulin recovered. There was less water in the
cake in this case* The mixture filtered slowly. Table VIII gives
the result of this experiment*
The Effect q£ Successive Recrystallizations on the Ash Content
and on the nature of the Product Recovered
Starting with 288 grams of inulin and using a ratio
of inulin to water of 1 to 4, four successive recrystalliza-
tions were made* This was done to determine the effect of
recrystallization on the ash content and on the nature of the
product recovered* The Inulin was allowed to precipitate
forty-eight hours in each case before it was filtered*
22
TABLE VIII
THE EFFECT OF REDISSOLVING; ALSO
THE EFFECT OF CONSTANT STIRRING
300 gms. Inulin
Number of Times
Redissolved
None One Two
Three
Stirrec
12 hr s.
Stood
12 hrs.
Number of Hours
Before Filtering
24 48 72 96
Cake
Weight
gms*
146.8 125.8 147 115.5 108.4
Per Cent
Inulin
32*3 32.3 33.4 34 43
Dry
Inulin
Weight
gms*
47.3 43.1 49
39.2 46.7
Nature Mixture Same Same Same
Mixture
Per Cent
Recovered
78.9 72 81.5 65.2 78
Residue
From
Filtrate
Weight
gms*
9
13.2 8.7 15.5 7
Per Cent 15
22 14.5 25.8 11.6
Total
Recovered
j
23
A determination of the ash content was made on the
starting material and on the dry inulin from each recrystal
lization. An ash determination was also made on the residues
from the filtrates. The first recrystallization showed a
considerable decrease in ash content compared with that of
the starting material. The second and third recrystallizations
showed less decrease in ash content end the fourth gave a very
low determination for ash. It was thought that the ash content
would not be decreased appreciably by further recrystallizations.
The first, second, and fourth recrystallizations gave
the desirable, white, amorphous form of inulin, while the
third recrystallization gave the undesirable, granular, horny
form. This showed that the 1 to 4 ratio did not always produce
the desirable form. The yield of inulin, which increased with
each recrystallization, was only slightly greater the fourth
time than the third, indicating that the increase would not
be appreciable for further recrystallizations. Table IX gives
the result of this experiment.
The Effect of Standing for Short Periods of Time on the Mature
of tdie product
Weight of Inulin -— 240 grams
Volume of Water------ 1500 cc
This experiment was performed in an effort to determine
what factors, other than the 1 to 4 ratio, entered In to give
24
TABLE IX
THE EFFECT OF SUCCESSIVE RECRYSTALLIZATIOHS
ASH CONTENT OF STARTING MATERIAL 0.42$
Grams of Inulin
at Start
288 221 157 130
Recrystallizations 1 2 3 4
Cake
Weight
gms.
684.2 524.9 388.1 354.4
Per Cent
Inulin
34.4 36.5 37.4 34.5
Dry
Weight
gms.
234.4 191.4 144.9 121.4
Nature
White
Amorphous
Same
Horny
Granular
White
Amorphous
Inulin
Per Cent
Recovered
81.7 86.6 92.3 93.4
Per Cent
Ash
0.13 0.06 0.02 0.005
Residue
Weight
gms.
26.5 9.5 6 4.8
From
Per Cent 9.22 4.3 3.8 3.7
Filtrate Per Cent
Ash
3 2 0.55 0.12
25
the desirable form of inulin* The impure inulin was dissolved
in hot water and the solution was filtered and then divided
into four equal parts*
Two of the solutions were cooled with ice and filtered
after one hour and three hours, respectively* The third part
was filtered after five hours and the fourth after eight hours*
The cake was weighed and dried in each case and the form of
dry inulin was noted and recorded* The filtrate from each was
allowed to stand in a beaker until the total number of hours
each part stood was forty-eight hours* It was then filtered
again and the cake dried*
The experiment did not show what other factors besides
the 1 to 4 ratio entered in to give the white, amorphous
inulin but did show that it was not necessary for the filtrate
to stand seventy-two, forty-eight, or even twenty-four hours
before the white, amorphous inulin was obtained* The experiment
also showed how the amount of inulin recovered increased with
the time of standing* It was noted that the 'second filtration
in each case was very slow and the filter paper was hard to
remove from the cake* Table X gives the result of this experiment*
The Effect of Time of Heating on the Mature of the Product
It was thought that the nature of the product might
vary with the length of time the solution was heated before
filtering* In order to find out if this were true, two 40-gram
26
TABLE X
THE EFFECT OF STANDING FOR SHORT PERIODS OF TIME
240 gms. Inulin
Hours Before
Filtration
1
3 5 8
Cake
Weight
gms.
46.2 102.8
109.5
111.5
Per Cent
Inulin
35.5 34.5 35.9
37.2
Dry
Inulin
Weight
gms.
16.5
35.5
39.2 41.5
Nature Mixture
Amorphous
White
Amorphous
White
Amorphous
White
Per Cent
Recovered
27.5 59.2 65.5 69.2
27
samples of impure inulin were dissolved in water (1 to 4 ratio).
In one case* the solution was heated at a temperature of 90°
to 95° G. for only five minutes before filtering while the
other was heated at the same temperature for thirty minutes
before filtering. The filtrates stood for forty-eight hours.
The nature and weight of the dry inulin were noted and recorded
in each case.
The white, amorphous, desirable form of inulin was
obtained when the solution was heated for thirty minutes and
the granular, horny, undesirable form was obtained when the
solution was heated for only five minutes; also, the amount
of inulin recovered was greater when the solution was heated
for thirty minutes. Table XI gives the result of this experiment.
The Effect of Temperature of Heating on the Hature of the Product
The purpose of this experiment was to determine the
effect on the nature of the product of dissolving the inulin
in water at different temperatures.
Two 100 gram samples of inulin were weighed out. The
o o
first was added to 400 cc of water at 96 - 98 C. and the
o o
second was added to 400 cc of water at 78 - 80 C. The solutions
were held at the respective temperatures for twenty minutes
after the inulin was added. After filtering, each was set
aside in a covered beaker for forty-eight hours in order to
allow precipitation to take place. The water was then filtered
TABLE XI
THE EFFECT OF TIME OF HEATING
Time of
Heating
5 minutes 30 minutes
Weight of
Inulin
40 gms. 40 gms.
Cake
Weight
gms.
100 82.5
Per Cent
Inulin
30.7 45.8
Dry
Inulin
Weight
gms.
30.7 37.8
Nature
Granular
Horny
White
Amorphous
. Per Cent
Recovered
76.8 94.5
.Residue
From
Filtrate
Weight
gms.
4.2 3.3
Per Cent 10.5 8.3
29
off and the cakes dried.
The same granular form of inulin was obtained in both
cases. The lower temperature gave the highest yield but the
precipitated inulin filtered slowly and stuck to the filter
paper. The lower yield obtained with the higher temperature
can be accounted for by the fact that inulin hydrolyzes readily
at temperatures near the boiling point.
The temperature best suited to dissolving the inulin
was found to be 90°- 95° C. Table XII gives the result of
this experiment.
A Comparison of the Solubility of the Cake and the Dry Inulin
The solubilities of the cake and the inulin were
o o
compared at 50 C. and at 80 C. Because of the colloidal
suspension present in each case, the results represent the
weight of inulin that passed through the filter paper at these
temperatures rather than the true solubilities. The figures
do serve as a means of comparing the solubilities however,
since the values found checked quite closely.
A saturated solution was formed in each case in a constant
temperature bath and then the solution was filtered quickly
with the aid of suction. Twenty-five cc of the solution were
pippetted off and evaporated to dryness. Since the cake was
approximately 66 2/3 per cent water, about three times as much
of it was required to saturate the solution as was required
of the inulin.
30
Solubility in Grams per 100 ce of Water
50 80
Inulin
7.6 18.6
Cake 7.55 18.7
Weight of Cake Dissolved 22.7 56.7
The result showed that the solubility of the cake was
the same as that of the dry inulin.
TABLE XII
THE EFFECT OF TEMPERATURE OF HEATING
100 gras. Inulin
Temperature
of Heating
o o
76-78 96°-98°
Weight of Inulin
100 gms. 100 gms.
Cake
Weight
gms •
246.5 287
Per Cent
Inulin
34.8 29
Dry
Inulin
Weight
gms.
85.5 83
Nature
Granular
Horny
Granular
Horny
Per Cent
Recovered
85.5 83
Residue
From
Filtrate
Weight
gms.
7
9
Per Cent 7
9
32
SUMMARY
Washing; the Cake With. Alcohol
When the cake was washed with alcohol, the white,
powdery form of inulin was obtained which was more desirable
than the granular, translucent, horny form. In most cases,
a larger amount of inulin was recovered from the alcohol wash
than from the water wash. One objection to the method, how
ever, is the cost of alcohol.
Hydrogen-ion Concentration
A slight hydrogen-ion concentration was effective in
throwing down the colloidal suspension. This advantage was
completely outweighed by the fact that the acid produced a
darkening of the recovered dry inulin. This darkening was
confirmed by a second experiment with a more thorough washing*
Washing the Cake With Water at 0° and at 25°C,
More inulin was recovered when the cake was washed
with water at 0°C« The amount was, however, only slightly
more than that obtained when the temperature of the wash water
was 25°C,
Time of Standing
33
Seventy-two hours of precipitation gave the largest
amount of inulin recovered* Since there is danger of fermen
tation with such long standing and since the amount recovered
was only slightly less for forty-eight hours, it would be
advantageous to use the shorter period of time for precip
itation* 1
The Ratio of Inulin to Water
The most desirable starch-like form and the greatest
amount of inulin were recovered by using the 1 to 4 ratio of
inulin to water, respectively* This ratio, however, did not
give the most desirable form in all cases*
Redissolving the Precipitated Inulin
The colloidal suspension was not removed by redissolving
the precipitated inulin several times* It was shown that re
dissolving may cause the formation of a supersaturated solution*
Recyrstallizatlon and Ash Content
The ash content decreased with the number of recrystal
lizations* This decrease was very marked at first but after
the fourth crystallization, became almost constant*
Standing For Short Periods of Time
When precipitation of the inulin was allowed to take
34
place for less than twenty-four hours, the amount recovered
was considerably lower and the form of the inulin was not improved.
It was shown that the precipitation was quite rapid for the first
twenty-four hours*
Time of Heating
She most desirable form of inulin was obtained when the
solution in which the inulin was dissolved, was heated for thirty
minutes* ©lis time of heating also gave the greatest amount of
inulin recovered*
Comparison of Solubility of Cake and Inulin
It was found that at 80°C* and at 50°C*, the solubilities
of the cake and the inulin were the same. Since the cake contained
about 66 2/3 per cent water, three times as much of it was required
to make a saturated solution as was required of the dry inulin.
35
CONCLUSION
The results of this investigation on the behavior of
inulin in solution indicate the best procedure to follow in
crystallization of inulin. In order to obtain the most desirable
form, and the greatest amount of inulin recovered, the following
procedure is recommendedi
1 Ratio of inulin to water — 1 to 4.
2 Time of heating — thirty minutes.
3 Time for precipitation — forty-eight hours or seventy-
two hours in well covered vessels.
4 Washing with ice water or with alcohol.
5 Number of recrystallizations to procure product of
absolute purity — four.
o ^
6 Temperature of heating -- 90 - 95 C.
i
Rat»o o
/' 6
lin to W a t e r
N umber of H ours for P reci pi t a t i o n
OQ
!
BIBLIOGRAPHY
39
A. BOOKS
j,
Armstrong, E. F. and Armstrong, K. F., The Carbohydrates.
New York: Longmans, Green and Company, 1934*
Beilstein, Kandbuch der Organ!ache Chernie I, 1095*
Dragendorf, Materialien Zu iener Monograph!e des Inulins.
St. Petersburg, 1870.
Oppenheimer, Die Methodik der Fermente. Leipzig, 1927, p. 288
Pringsheim, Hans, The Chemistry of the Saccharides. New York:
Seidell, Atherton, Solubilities of Inorganic and Organic
Compounds. New York: D* Van Nostrand Company, 1919.
Thorpe, J. F., Thorpe^ Dictionary of Applied Chemistry.
New York: Longmans, Green and Company, 1937.
B. PERIODICAL ARTICLES
Grafe and Vauk, Biochem. Z., 43,424 (1912)
Haworth, Hirst, and Percival, J. Chem. Soc., 2834, (1932)
Hoche, Z. ver. deut. Zuckerind., 821, 1926
s Kiliani, Ann.. 205,145, 1880
McGlumpy, Scientific American., vol. 99, Oct. 1908
McGlumpy, "Commercial Production of Levulose," Industrial
and Engineering Chemistry, 23:1202-4, Nov ember,' 1931.
McGlumpy, "Sugar From Artichokes,” Journal of Food Industry,
4:66-7, February, 1932
Ohlmeyer and Pringsheim, Ber., 66,1292, (1933)
Pringsheim and Fellner, Ann., 462,231 (1928)
40
Pringsheim and Reilly, Ber., 61,2018 (1928)
Schluback and Eisner, Ber., 62,1493 (1929)
Tanret, Bull. Soc. Chim.. (3) 9,200,227,625 (1893)
Yanovsky, E., and Kingsbury, R. M., "Solubility of Inulin,”
Journal of the American Chemical Society. 55:3658, 1933.
C. UNPUBLISHED MATERIALS
Bartel, A. W., "Inulin- Purification and Study,” Unpublished
Master*s Thesis, University of Southern California, Los
Angeles, California, 1937.
Black, "Commercial Value of Levulose," Unpublished Master*s
Thesis, University of Southern California, Los Angeles,
California, 1927.
Holzman, "Studies in the Production of Inulin," Unpublished
Master’s Thesis, University of Southern California, Los
Angeles, California, 1938.
Poorman, "Problems in Levulose Crystallization," Unpublished
Master’s Thesis, University of Southern California, Los
Angeles, California, 1938.
Rieger, "Commercial Preparation of Levulose," Unpublished
Master’S Thesis, University of Southern California, Los
Angeles, California, 1934.
Vivian, "Levulose," Unpublished Master *s Thesis, University
of Southern California, Los Angeles, California, 1922*

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Asset Metadata

Creator Brobst, W. H (author)

Core Title A study of the behavior of inulin in solution

Degree Master of Science

Degree Program Chemistry

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag chemistry, organic,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor [illegible] (committee chair), [illegible] (committee member), Johnstone, George R. (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c17-787528

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