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UDC 665.3 : 620.1 Ref. No. : ISO/R 658-1968 (E)
IS0
I N T E RN AT I ON A L O R G A N I2 AT I ON FOR S TA N DARD I ZATl O N
IS0 RECOMMENDATION
R 658
OLEAGINOUS SEEDS
DETERMINATION OF IMPURITIES
1st EDITION
February 1968
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of IS0 Recommendations and IS0 Standards
The copyright
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 658, Oleaginous seeds - Determination of impurities, was drawn
up by Technical Committee ISO/TC 34, Agricultural food products, the Secretariat of which is held
by the Magyar Szabvhyügyi Hivatal (MSZH).
Work on this question by the Technical Committee began in 1960 and led, in 1963, to the
adoption of a Draft IS0 Recommendation.
In March 1966, this Draft IS0 Recommendation (No. 899) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature,
by the following Member Bodies :
Australia Hungary Poland
Belgium India Romania
Bulgaria Iran South Africa,
Chile Ireland Rep. of
Colombia Israel Turkey
Czechoslovakia Italy U.A.R.
Finland Netherlands United Kingdom
France New Zealand U.S.S.R.
Germany
Norway Yugoslavia
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council
which decided, in February 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 658-1968 (I
IS0 Recommendation R 658 February 1968
OLEAGINOUS SEEDS
DETERMINATION OF IMPURITIES
1. SCOPE
This IS0 Recommendation describes a method for the determination of impurities in oleaginous seeds
used as primary industrial materials, and defines the various categories of impurities as usually under-
stood.
2. DEFINITIONS
2.1 By impurities are meant all foreign matter, organic and inorganic, other than seeds of the basic
species.
2.2
By fines are meant the particles passing the sieves shown in Table 1 (see clause 5.2.1), according
to the species being analysed.
In the case of groundnut, meal from the seeds contained in the fines is not regarded as an
impurity.
2.3 By non-oleaginous impurities are meant non-oleaginous foreign bodies (bits of wood, pieces of
metal, stones, seeds of non-oleaginous plants), fragments of stalks, leaves and ail other non-
oleaginous parts belonging to the oleaginous seed analysed (for example bits of shell, loose or
adhering to palm kernels), retained by the sieves with holes of the diameters given shown in
Table 1. In the case of seeds sold in their shell, for example sunflower seeds (Helzimthus annuus
Linnaeus) pumpkin seed (Cucurbita pep0 Linnaeus), the loose shells are regarded as impurities
only if their proportion is larger than that of the corresponding kernels present in the same sample.
2.4 By oleaginous impurities are meant foreign oleaginous seeds
3. PRINCIPLE
Separation of the impurities by sieving and sorting, into three categories
- fines,
- non-oleaginous impurities,
- oleaginous impurities.
Determination of the mass of each category.
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ISO/R 658-1968 (E
4. APPARATUS
4.1 Sieves (see Table 1).
4.2 Tiveezers or other suitable instruments.
4.3 Analytical balance,
5. PROCEDURE
5.1 Test portion
The test portion is the analysis sample obtained by reduction of the contract sample according
to IS0 Recommendation R 664, Oleaginous seeds - Reduction of contract samples to samples
for analysis.
Weigh the test portion with a precision of at least 0.1 O/'.
5.2 Determination
The determination of impurities should be carried out sufficiently quickly to avoid any appre-
ciable change in the moisture content of the seed.
5.2.1 Separation offines
Separate the fines quantitatively by sieving the test portion, using a sieve with circular holes
of the diameter shown in Table 1. Collect the fines and weigh them to the nearest 0.01 g.
TABLE 1. - Diameter of holes of sieves
5.2.1.1 In the case of groundnut, collect the total fines thus obtained, which include non-
oleaginous fines and fines from the seed, weigh these to the nearest 0.01 g and deter-
mine their oil content. Determine also the oil content of the pure seeds, in order to
calculate the content of non-oleaginous fines.
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ISO/R 658-1968 (1
5.2.2 Separation of oleaginous and non-oleaginous impurities
5.2.2.1 GENERAL CASE (copra, seeds of medium size)
In the material retained by the sieve shown in Table 1, separate by means of tweezers
(or any other suitable instrument) the non-oleaginous impurities (2.3) on the one hand,
if necessary detaching bits of shell adhering to the seeds (e.g. palm kernels), and the
oleaginous impurities (2.4) on the other hand.
Weigh separately, to the nearest 0.01 g, each category of impurities.
If specified in the contract, note the nature of the oleaginous impurities in order that
this may be recorded in the test report.
5.2.2.2 SMALL SEEDS
Transfer the residue from the sieve shown in Table 1 to a second sieve so as to retain
impurities larger than the seeds (or separate these impurities by means of tweezers or
any other suitable instrument).
Sort this fraction into non-oleaginous impurities (2.3) and oleaginous impurities (2.4).
Weigh separately, to the nearest 0.01 g, the fines and the two fractions of impurities
(non-oleaginous and oleaginous) larger than the seeds, and a
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