INTERNATIONAL
STANDARD 749
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION l MEXAYHAPOAHAII OPl-AHM3AUMII l-IO CTAHAAPTM3AUMM l ORGANIZATION INTERNATIONALE DE NORMALISATION
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ilseed residues - Determination of total ash
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Tourteaux de graines oGagineuses - De’termination des cendres totales
First edition - 1977-10-01
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UDC 665.117 : 543.822 Ref. No. IS0 749-1977 (E)
Descriptors : oilseeds, oilseed residues, chemical analysis, determination of content, ash.
Price based on 2 pages
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FOREWORD
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IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 member bodies). The work of developing
International Standards is carried out through IS0 technical committees. Every
member body interested in a subject for which a technical committee has been set
up has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work.
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Draft International Standards adopted by the technical committees are circulated
to the member bodies for approval before their acceptance as International
Standards by the IS0 Council.
International Standard IS0 749 was developed by
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Technical Committee
ISO/TC 34, Agricultural food products.
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It was submitted directly to the IS0 Council, in accordance with clause 6.12.1 of
the Directives for the technical work of ISO. It cancels and replaces IS0
Recommendation R 749-1968, which had been approved by the member bodies of
the following countries :
Australia India Romania
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Brazil Iran South Africa, Rep. of
Bulgaria Ireland Thailand
Chile Israel Turkey
Colombia Italy United Kingdom
Czechoslovakia Korea, Rep. of U.S.S.R.
France Netherlands Yugoslavia
Germany Poland
Hungary Portugal
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The member body of the following country had expressed disapproval of the
document on technical grounds :
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Canada
0 International Organization for Standardization, 1977 l
Printed in Switzerland
INTERNATIONAL STANDARD IS0 749-1977 (E)
Oilseed residues - Determination of total ash
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1 SCOPE AND FIELD OF APPLICATION 5.5 Electrically I
heated muffle furnace, with air circulation
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and capable of being controlled at 650 ? I5 “C.
This International Standard specifies a method for the
determination of the total ash from residues (excluding
compounded products) obtained by the extraction of oil
5.6 Desiccator, containing an efficient desiccant.
from oilseeds by pressure or solvent.
6 PROCEDURE
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2 REFERENCES Make all weighings to the nearest 0,001 g.
I SO 735, Oilseed residues - Determination of ash insoluble
6.1 Preparation of the test sample
in hydrochloric acid.
6.1.1 Take the contract sample obtained in accordance
IS0 771, Oilseed residues - Determination
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of moisture
with IS0 5500.
and volatile matter con tent.
IS0 5500, Oilseed residues - Sampling. 1) 6.1.2 Grind the contract sample, if necessary, in the
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previously well cleaned mechanical mill (5.2). First, use
about one-twentieth of the sample to complete the cleaning
3 DEFINITION of the mill, and reject these grindings; then grind the rest,
collect the grindings, mix carefully and carry out the
total ash : The residue obtained after incineration at
analysis without delay.
550 + I5 “C under the operating conditions specified
below.
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6.2 Test portion
6.2.1 Weigh the incineration dish (5.4), previously heated
4 PRINCIPLE
for I5 min in the furnace (5.5) at 550 + I5 ‘C, and allowed
Incineration of a test portion at 550 + 15 “C in an to cool in the desiccator (5.6) to laboratory temperature.
electrically heated muffle furnace, until practically constant
mass is reached. 6.2.2 Weigh into the incineration dish about 5 g of the
test sample (6.1.2), spread this uniformly over the whole
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base of the dish and re-weigh.
5 APPARATUS
Carry out these operations as quickly as possible, in order
to avoid any appreciable change in moisture content.
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5.1 Analytical balance.
NOTE - If the total ash is not
used subsequently for the determi-
5.2 Mechanical mill,
easy to clean and allowing the nation of the residue insoluble in hydrochloric acid (see IS0 735),
the test portion may be reduced to 2 g.
residues to be ground, without heating and without appreci-
able change in the moisture, volatile matter and oil content,
to particles passing completely through the sieve (5.3). 6.3 Determination
Place the dish containing the test portion on an electric
5.3 Sieve, with apertures of diameter I mm. hot-plate or over a gas flame, and heat progressively until
the test portion carbonizes, then place in the furnace (5.5),
5.4 Flat-bottomed incineration dish, of diameter about controlled at 550 + I5 “C. Continue heating until a white,
60 mm and height not exceeding 25 mm, of platinum, light grey or reddish ash is obtained, visibly free from
platinum-plated gold, silica or, if not available, porcelain. carbon particles (generally at least 2 to 3 h).
1) In preparation.
IS0 749-1977 (E)
Allow the d ish to cool in the desiccat or and weigh when it Take as the result the arithmetic mean of the two determi-
has reached labora tory temper nations, provided that the requirement concerning
repeatability (see 7.2) is satisfied. Otherwise, repeat the
Replace the dish in the furnace and continue heating for determination on two other test portions. If this time the
1 h at 550 + 15 “C. Allow the dish to cool and re-weigh, as difference again exceeds 0,2 g per 100 g of sample, take as
before. the result the arithmetic mean of the four determinations
carried out, provided that the maximum difference between
If the difference between the two weighings is less than or
the individual results does not exceed 0,5 g per 100 g of
equal to 0,002 g, regard the determination as finished. If
sample.
not, continue with 1 h periods in the furnace until the
difference between two successive weighings is less than or Report the result to one decimal place.
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equal to 0,002 g.
If the ash is rather blackish after the first incineration of 2 9.1.2 If requested, the total ash may be expressed in
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or 3 h, it may be moistened with a few drops of a 200 g/l relation to the dry matter by multiplying the result
solution of ammonium nitrate (not in excess so as to avoid obtained in accordance with 7.1 .I by
dispersion and sticking together of the ash). After drying in
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an oven, resume the calcination. If necessary, repeat the
operation until incineration is complete. 100-u
Carry out two determinations on the same test sample. where U is the percentage by mass of moisture and volatile
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matter determined as specified in IS0 771.
7.2 Repeatability
7 EXPRESSION OF RESULTS The difference between the results of two determinations
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carried out simultaneously or in rapid succession by the
7.1 Method of cakulation and formulae same analyst should not exceed 0,2 g of total ash per 100 g
of sample.
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7.1.1 The total ash yielded by the sample as received,
expressed as a percentage by mass, is equal to
8 TEST REPORT
m2 -Iy)o The test report shall show the method used and the result
x100 obtained, indicating clearly whether the result is expressed
“I -mQ
in relation to the product as received or in relation to the
dry matter. It shall also mention any operating conditions
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not specified in this International Standard, or regarded as
m. is the mass, in grams, of the dish; optional, as well as any circumstances that may have
influenced the result.
ml is the mass, in grams, of the dish and test portion;
The report shall include all details required for complete
m2 is the mass, in grams, of the dish and ash. iden tif icatio n of the samp le.
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