Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station ; 57-8
Title: Inositol as a possible by-product from citrus
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Permanent Link: http://ufdc.ufl.edu/UF00072385/00001
 Material Information
Title: Inositol as a possible by-product from citrus
Series Title: Citrus Station mimeo report
Physical Description: 3 leaves : ill. ; 28 cm.
Language: English
Creator: Wolford, R. W
McNary, Robert R
Dougherty, Marshall H
Citrus Experiment Station (Lake Alfred, Fla.)
Florida Citrus Commission
Publisher: Florida Citrus Experiment Station :
Florida Citrus Commission
Place of Publication: Lake Alfred FL
Publication Date: 1956
 Subjects
Subject: Citrus -- By-products -- Florida   ( lcsh )
Inositol   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (leaf 3).
Statement of Responsibility: R.W. Wolford, R.R. McNary, and M.H. Dougherty.
General Note: Caption title.
General Note: "October 11, 1956."
 Record Information
Bibliographic ID: UF00072385
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 74906708

Full Text




Citrus Station Mimeo Report 57-8
October 11, 1956

Inositol as a Possible By-Product from Citrus
R. W. Wolford, R. R. McNary, and M. H. Dougherty


Inositol has been known for more than a century as a common constituent of
living matter. Because of its widespread occurrence in both plants and animals,
much work has been done to determine its importance in nutritional and biological
functions. Chemically, inositol is a hexahydroxycyclohexane- C6H6(OH)6 (Fig. 1)-
a compound existing in nature in the form of many isomers and derivatives. It is
found in both the free and combined forms. One of the optically inactive isomers,
i-inositol or meso-inositol, possesses important biological activity in contrast
to the other compounds of similar stereoisomeric structure. Pure meso-inositol
is a white, crystalline, odorless substance having a melting point of 22500. It
is soluble in water, slightly soluble in alcohol and practically insoluble in
other organic solvents.

The occurrence of inositol in citrus juices has been investigated by a
number of workers. Nelson and Keenan (1) have reported yields of inositol ob-
tained from various citrus fruits. Cheldelin and Williams in a report by the
University of Texas (2) determined the inositol content of orange and grapefruit
juices by means of a yeast assay method. Krehl and Cowgill (3) in a study of the
vitamin content of citrus products have presented results by the yeast assay
method for inositol in fresh, canned, and concentrated orange, grapefruit, and
tangerine juices. Bornstein (4) presented a method for the isolation and recov-
ery of inositol from dried citrus peel. Baier and Manchester (5) have reported
the inositol content of citrus fruits by microbiological assay.

Investigations in this laboratory toward the isolation and recovery of
inositol were prompted by the fact that citrus is one of the richest sources of
inositol and that this compound held interesting by-product possibilities.

The present commercial methods for the production of inositol were developed
in the corn products industry where it is obtained from the corn steep liquor.
In this waste material the source of inositol is found in the phytin, which is
the mixed hydrogen-calcium-magnesium salt of inositolhexaphosphoric acid. Since
this is not the case in citrus fruits, established recovery procedures were
found not to be applicable and this presented new problems.

While studying methods for the economical recovery of inositol from citrus
fruits, peel and liquids from other by-product processes, much time has been re-
quired in the development of methods for the analysis of inositol in these
substances.

In all of the previously published results indicating the amount and
occurrence of inositol in citrus, acid hydrolysis has been used prior to analysis
and as an integral part of the isolation procedure. Whether other workers have
been unaware of the occurrence of inositol in citrus fruit as the free form, and
not as a combined inositol requiring acid hydrolysis, is not altogether clear.
Paper chromatographic analysis has made possible the identification of inositol

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
711a 10/11/56 RWW














Figure 1


C -.---.- C(
/ OH OH



H/


C


H /
OH _.
OH H


H H
C .----- G










C C
H OH
OH H


OH
CH
OH


d glucose


i inositol


Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
711 10/11/56 RWW









in citrus fruits and juices as a free material. This was accomplished by chro-
matographing a solution of known inositol on the same chromatogram with the juice
sample. Further identification was accomplished by elution of the inositol spot
from the paper, crystallizing, and determining its melting point and reaction to
the Scherer test (6). A number of semi-quantitative determinations of inositol
have been carried out on paper chromatograms by densitometry and by periodic
acid oxidation of the eluted inositol. These analyses made before and after acid
hydrolysis showed no apparent increase in inositol after hydrolysis. Acid hy-
drolysis of any combined inositol would have caused cleavage and liberation of
more inositol.

Some significant progress has been made in the separation and recovery of
inositol from citrus juices, citrus peel, and other liquors. In the course of
developing methods for recovery, four small quantities of meso-inositol of good
purity have been obtained. Variations in the methods of recovery ranged from
treatment of the sample by acid hydrolysis with 6N HC1 under reflux for 24 hours
to alkaline extraction with subsequent acidification. Chemical precipitation
procedures have also been employed for the precipitation of inositol by mechani-
cal means as well as the formation of metal ion complexes. Considerable vari-
ation in the procedures for the crystallization of inositol from the crude
extracted solutions have been made. None of the variations have affected the
apparent purity of the crystalline inositol obtained. These facts provide further
evidence of the chemical stability of meso-inositol as it is obtained from citrus
juices and other materials.

At the present time inositol is being marketed at $4.50 to $5.00 per pound.
The best information obtained to date shows that the entire production of inositol
from corn steep liquor has been going into pharmaceutical products. Information
received recently reveals the interest in the paint industry for obtaining meso-
inositol to be used as a chemical polyol. It has been suggested that inositol
might be used in the production of plastics. There are likewise, a number of
derivatives of inositol which might have important possibilities as additional
by-products. All of the suggested applications for the use of inositol would
provide good marketability if the cost of production could be reduced to permit
its use as a chemical.

It is the object of this investigation to determine the occurrence of
inositol in citrus fruits and other liquors and to develop a process for the
low cost production of meso-inositol. The recovery of inositol in the citrus
industry may logically be made an integral part of other established processes
for the recovery of by-products now being carried out in this industry. Because
of its chemical stability and its preferential solubility in water, it is not
destroyed in any of the by-product processes which we have investigated for
possible extention to inositol recovery.

Further work is planned toward the development of the economical recovery
of inositol and it is believed that inositol may become a valuable citrus by-
product.


Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
711b 10/11/56 RW







-3-

LITERATURE CITED


1. Nelson, E. K. and Keenan, G. L. i-Inositol in Citrus Fruits. Science, 77,
561 (1933).

2. Cheldelin, Vernon H. and Williams, Roger J. The B Vitamin Content of Foods.
Univ. of Texas Pub. 4237, 105-24 (1942).

3. Krehl, W. A. and Cowgill, George R. Vitamin Content of Citrus Products.
Food Research l_, 179-91 (1950).

4. Borstein, Lawrence J. Extraction of Inositol from arted Citrus Peels.
Thesis, Master of Science, Columbia Univ. Dept. of Engr. (1947).

5. Baier, W. E. and Manchester, T. C. Inositol and Folio Acid in Citrus Fruit.
California Citrograph 34, 361-4 (1949).

6. Scherer, J. von. Ueber den inosit. Annales der Chemie, Justus Liebigs 81
375, (1852).




























Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
711c 10/11/56 RW




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